A scheme for swept-source optical coherence tomography (SS-OCT) based on wavelength-encoded endoscopic imaging is presented and demonstrated in theory. The main principles involved in the imaging scheme are analyzed in detail. The mathematical analysis of the interference signal pattern in terms of ‘temporal impulse response’ and ‘spectral response’ is conducted. The simulated interferograms of simple samples and the decode results by Morlet wavelet are presented. The system key parameters such as transverse imaging resolvable points,imaging ranges,resolutions are detailed discussed. It is found that the transverse resolution and depth resolution are affected by each other,and an effective method to improve the system resolutions is to enlarge the swept range of the swept source.

Optical coherence tomography (OCT) is a promising new imaging method for clinical diagnosis and scientific research. In order to obtain the morphologic structure and the scattering coefficient of in vivo human skin,an OCT system with 16 μm axial resolution and -90 dB detection sensitivity is created. With this system in vivo OCT image of human skin in several locations is formed. And the heterodyne signal expression is deduced from the OCT model based on the extended Huygens-Fresnel principle. Through the fit of heterodyne signal expression to the various parts of the OCT axial signal curve,the scattering coefficients is acquired. Structures of the stratum corneum (plamoplantar),the epidermis,and the upper dermis can be identified from the obtained cross-sectional images. The thickness of the stratum corneum and the epidermis are measured,as well as the scattering coefficients. It is demonstrated that OCT is a feasible method for investigation of morphologic structure of superficial layers of human skin.

The skin tissues,which dealt separately by low-frequency ultrasound,80% glycerol and both of them,were observed by optical coherence tomography (OCT). The 1-D OCT image of epidermis and under 0.012 mm of the skin tissue surface were quantitative analysis by computer. The results of measurements showed that the low-frequency ultrasound and 80% glycerol not only can change the depth of light penetration of the skin tissue in short-time,but have synergistic effect on optical clearing of skin tissue in vitro.

Optical techniques based on measuring scattering properties of bio-tissues have a potential to determine internal physiological state. For tissue imaging,the least-scattered photons arriving at a detector may have a significant effect on the development of imaging algorithms. Tracing least-scattered photons may be helpful for further understanding of imaging mechanisms within current high-resolution optical-imaging techniques. Based on the vertex-propagator,a coordinate-tracing model is developed to search probabilities for least-scattered photons traversing in a scattering medium. Integral expressions for photon experiencing any time scattering events are obtained. Compared with the methods based on both geometrical tracing and Monte Carlo simulation,our model is simpler and easier for programming.

The image reconstruction in diffuse optical tomography (DOT) is regarded as a large-scale nonlinear optimization problem,whose solution strategy is usually based on a Newton-like iteration algorithm involving the construction and inversion of the Jacobian matrix. It becomes intractable,when the scale of the inverse problem is large. To overcome this problem,algebraic reconstruction techniques (ART),an iterative solving method based on row action,is proposed to reduce the computational effort,but which will result in poor image quality. In this paper,conjugate gradient (CG) method is employed here,which requires only the computation of the objective function gradient to avoid calculating and storing the whole Jacobian matrix. Step length is determined by inexact line search method. The proposed methodology is validated by reconstructing the image of the slab phantom containing two deeply-located absorption and scattering contrasting cubes. Compared with ART,we find that the CG method performs better than ART at the image quality ,convergence and the speed of it.

In order to obtain human eye fundus images with high spatial resolution,the liquid crystal (LC) adaptive optics (AO) systems was introduced to the traditional ophthalmoscopes. The AO system based on Shark-Hartmann wavefront sensor (SHWS) and liquid-crystal-on-silicon spatial light modulator(LCOS-SLM) could detect and correct the low and high orders eye′s aberrations,and obtain the human eye fundus images with high spatial resolution. It is a useful tool for early diagnosing the eye diseases and diseases interrelated to the eye. The open-loop and closed-loop mode were both adopted. They could both obtain human eye fundus images with high spatial resolution. The LC-AO system possesses a great potential in human eye fundus imaging with high spatial resolution.

We developed a 3D spectrum domain optical coherence tomography (OCT) system based on fiber-based Michelson interferometer. The measurable depth of the OCT imaging is up to 3.4 mm for the detection part is of high speed spectrometer with 0.05 mm spectrum resolution. The signal-noise-ratio (SNR) and axial resolution of this OCT system are experimentally found to be 51 dB and 8.5 m,respectively. A 3D OCT image could be acquired in two second owing to the fast A-scan rate (up to 10×103 line/s). Using 3D OCT technology,the images of biology tissue such as retina are shown more intuitive and precise.

The single-detector polarization-sensitive optical coherence tomography (PS-OCT) is studied,aiming at validating its ability to detect qualitatively the birefringence of biological tissue. The theory of single-detector PS-OCT detecting the birefringence of biological tissue was described,and the influence of birefringence on the Stokes vector was demonstrated with Monte Carlo simulation. A single-detector PS-OCT system was set up,which has a theoretical resolution of 10 μm,and experiment was performed on a bovine cartilage sample. The PS-OCT image indicated the birefringence of cartilage. The theoretical analysis and experiments results prove the ability of single-detector PS-OCT detecting tissue birefringence and the possibility of using single-detector PS-OCT in medical diagnosing domain.

Based on distinct patients and different design project,individual harmed model and restoration model can be built. According to the 3D simulation of maxilla,skull and dentition,standard mathematical model and entity model for maxilla repair can be provided. On the basis of scaned skull image,using CT image reconstruction technique and 3D finite element model (FEM),and the maxillofacial repair by restoration with rapid prototyping production technique,a good 3D FEM of normal maxillary and dentition and restoration are constructed. Then,configuration and function of maxillofacial are rebuilt after repair. 3D FEM of normal maxillary,dentition and restoration by CT image reconstruction,3D FEM and rapid prototyping production technique can be achieved with fine appearance,low cost and less post-operative complications. This method offer a complete idea for maxilla and dentition repair in clinic research.

This paper presents a transmissive rapid scanning optical delay line (RSOD) for balance detection based optical coherence tomography (OCT). This transmissive RSOD,consisting of a reflective blazed grating,a Fourier lens,a fast-scanning galvo-mirror,a right-angle prism and a mirror,possess functions of phase modulation,axial scanning and dispersion compensation in OCT just as a reflective RSOD. The developed transmissive RSOD is implemented in OCT for balance detection. Comparison study indicates that improved quality of imaging is archived by the transmissive RSOD based OCT,in contrast to that by a conventional reflective RSOD based OCT.

This paper proposes an iterative regularization denoising method based on Osher-Sole-Vese (OSV) model for medical image denoising. By using iterative regularization,the oscillating patterns of texture and details are added back to fit and compute the original OSV model,and the iterative behavior avoids overfull smoothing while denoising the features of textures and details to a certain extent. In addition,the iterative procedure is proposed in this paper. Experimental results show that the proposed method can achieve a better result in preserveing the texture and details for medical image denoising.

We present a full three-dimensional algorithm for time-domain fluorescence molecular tomography. A pair of appropriate transform-factors is employed to extract the featured information on the temporal profiles for time-domain coupled diffusion equations. The linear inversions at two distinct transform-factors are solved with an algebraic reconstruction technique,and the normalized Born ratio is proposed. The simulate phantom is measured in reflection and transmittance modes by use of multi-channel time-correlation single photon counting system. We experimentally validate that the proposed scheme can achieve simultaneous three-dimensional reconstruction of the fluorescent yield and lifetime. The results show that for the positions,sizes and shapes of the targets,there are some deviation in reflection measurement,the quality in transmittance one is better and in the two-mode is more satisfied.

By sending a micro-ultrasonic probe into coelom through biopsy channel of electronic endoscope,ultrasonic endoscope system can not only acquire pictures of the alimentary canal mucosal surface by direct observing,but also get images of the full histology of the digestive organs by ultrasonic scanning. In this paper,we introduced the coded excitation technique into the ultrasonic imaging system,which uses a 4-bit Barker coded pulse to excite the ultrasonic transducer resulting that the detecting depth and imaging quality of the medical ultrasonic endoscope be increased greatly with the peak negative acoustic pressure unchanged. Then we utilized the digital down conversion technique to realize medium frequency sampling,pulse compression and envelope extraction of the ultrasonic echo. Finally,using a glass beaker with ultrasonic coupling liquid as experimental sample,achieved a 256 gray-scale ultrasound image with the axial resolution of 0.4 mm,so the results proved the validity of system principle.

Spectral domain optical Doppler tomography (ODT) can achieve much higher imaging speed and velocity dynamic range than the time domain technology. A method to measure the absolute velocity is developed in a spectral domain ODT system,where Doppler angle is determined by combined information on the measured Doppler shift and Doppler bandwidth,and then the flow velocity is determined from Doppler angle and Doppler shift. Theoretical development relevant to Doppler measurement and absolute velocity determination is given. Measurement on flow velocity of aqueous solution of polystyrene beads in a capillary tube is done,in good agreement with the expected one. Finally,the developed method is applied to the study of rat’s cerebral arteries.

The nude mice which were injected with the human gastric cancer cells (SGC-7901) in their peritoneums were chosen as the animal models of gastric cancer peritoneal dissemination in our research. The laser-induced autofluorescence spectra of these mice which were in different tumor planting periods and the normal counterpart were taken in vivo during the simulated surgeries. The spectra of different tissue types were compared and classified by clustering analysis and discriminate analysis. The results indicate the intensities of reduced nicotinamide adenine dinucleotide (NADH) are gradually decreasing while the one of Protoporphyrin IX (PpIX) are increasing with the growing of the cancer cell. The distinguish of the normal group and the tumor groups with different growth times of cancer cells is quite obvious when the measure method of interclusters and cluster number were set to square euclidean distance and 3,respectively. The technology of laser-induced autofluores cence (LIAF) may help to increase the accuracy of distinguishing the carcinoma metastaticum during surgeries.

An optical setup was proposed and realized to integrate the two methods combining objective with subjective in a system to survey human eye wave-front aberration,which can measure the human eyes′ wavefront aberration with 4.8-mm artificial pupil when the natural pupil is dilated as objective measurement and the subject is watching optotypes as subjective measurement. The result datum from both objective measurement and subjective measurement is fused on feature level by information fusion method with the weighting factors,which is helpful to emphasize the advantages of both subjective and objective measurement. Considering the influence of neural system on human eyes,the fusion result can reasonably reflect subject's visual quality and give more detailed advices for ideal corneal customized ablation of human eyes.

The feasibility and validity of skull tissue ablation with pulse CO2 and Er:YAG lasers were evaluated. Healthy male New Zealand rabbits in vivo were used in the experiment. Skull tissue of animal model was completely exposed by surgeon with conventional methods,and then put on a PC-controlled motorized linear drive stage and moved repeatedly through the focused beam of both lasers with certain work distance and moving rate until an about 3 cm length ablation groove was obtained. Diamond drill was used as control group. The appearance and morphological changes of ablation groove were observed by naked eye and microscope. Following traditional histological process,the micrographs of ablation groove′s cross-section slices were obtained,and its geometry and thermal injury thickness were measured. The ablation rate and ablation efficiency for both lasers were also compared. It shows that both lasers can be used for bone hard tissue ablation and similar outcomes as diamond drill were obtained. Pulse CO2 laser presents high ablation rate with strong thermal damage,while Er:YAG laser shows better outcomes compared with CO2 laser with higher ablation efficiency and smaller thermal injury. Furthermore,light absorption by blood during operation will reduce ablation efficiency and increase thermal injury which should be controlled efficiently in clinical application.

This letter compared the classical Pennes bioheat transfer model and the thermal wave model of bioheat transfer,which have often been used to describe the photothermal response on laser-tissue interaction. The conditions and influence factors of these two models were analyzed. The results show that when the laser-irradiated duration time is comparable to or shorter than the thermal release time in biological tissue,the results obtained by the thermal wave model and the classical Pennes bioheat transfer model are obviously different. The thermal damage assessment based on the latter model may cause more error. For the thermal wave model,the non-Fourier effect is more obvious in shallow area. The effects of blood perfusion rate and absorption coefficient of the first layer tissue on transient temperature and its characteristic at the irradiated origin were investigated.

A Mueller matrix measuring device of canted incidence and perpendicular detecting is designed. Combined with new data processing algorithm,the device measured the backscattering Mueller matrix of biomimetic and biological tissue. The research of biological tissue and other turbid medium through this way has potential value in turbid media testing and medical diagnosis.

The propagation of ultrasound modulation scattering signal in two-layered and three-layered biological tissue was studied with Monte Carlo simulation. The relations with the modulation scattered light intensity and its modulation depth contributed by the thickness,absorption coefficient,scattering coefficient and anisotropy coefficient of homogeneous and layered tissue were figured out. The results of Monte Carlo simulation show that the modulation scattering light is dependent on the optical properties and configuration of tissue,but the modulated depth of the modulated light doesn′t change in the propagation and is only dependent on the optical and ultrasonic properties of biological tissue within the ultrasound zoom. So the modulated depth is a key factor in ultrasound-modulated optical tomography. These works will conduce to reconstruct the tissue imaging effectively and reliably.

The aim of the study is to evaluate the ablation threshold of enamel of human permanent tooth for Er:YAG laser and Er,Cr:YSGG laser. 70 enamel samples were treated with increasing energy densities of 2~10 J/cm2. The surface changes were assessed by means of reflected light microscope and scanning electron microscope. Both Er:YAG laser and Er,Cr:YSGG laser are effective in ablating human tooth enamel. The ablation threshold value of Er:YAG laser in dental enamel is 3.19~4.36 J/cm2. As to Er,Cr:YSGG laser,the ablation threshold value is 4.12~4.80 J/cm2 .

The effect of low-power He-Ne laser irradiation on the function and expression of CD59 on T cells in tumor-bearing mice is studied. 40 BALB/C mice were randomly and evenly divided into four groups:tumor-bearing mice were constructed in groupⅡⅢⅣ,while groupⅠwere treated as normal control. Thymus region of mice in group Ⅲ were irradiated every day and mice in group Ⅳ were irradiated every two days. The growth of tumors were noted by tumor growth curves. The mice were executed 20 days later and T cells were segregated from thymus. The expression of CD59 on T cells from thymus was detected by immunohistochemistry and immunofluorescence;lymphocyte proliferation in thymus was detected by lymphocyte transformation test (MTT assay);IL-2 was detected by enzyme-linked immunosorbent array (ELISA);Laser scanning confocal microscope imaging of the calcium fluorescent indicator dye Fluo-3/AM was used to determine the kinetic changes of [Ca2+] in T cell endochylema. CD25+ T cells were determined by flow cytometer .The experiments show that tumor growth was inhibited after laser irradiation.The expression of CD59 protein,the proliferation of lymphocytes,level of IL-2,degree of the [Ca2+] and the expression of CD25 in group Ⅱ,Ⅲ,Ⅳ were decreased compared with group Ⅰ,but were increased in group Ⅲ,Ⅳcompared with group Ⅱ. The results indicate that the low expression of CD59 was improved after irradiation by low-power He-Ne laser,and irradiation can enhance the function of T cells.

UV-mediated apoptosis is a highly complex process in which different molecular pathways are involved. These include DNA damage,triggering of cell death receptors and the broken of mitochondria. It has been reported that DNA damage which is induced by UV irradiation can active the tumor suppressor p53 and trigger a cascade response of cell apoptosis. One of the most importment thing is the expression of PUMA is upregulated. However,the mechanism of PUMA-mediated apoptosis and Bax translocation after UV irradiation remains unclear. In this study,the fluorescence resonance energy transfer (FRET) technique was used to study the dynamic interaction among PUMA,Bax and Bcl-Xl in living single-cells. ASTC-a-1 cells were transiently co-transfected with GFP-PUMA and YFP-Bcl-Xl or CFP-Bcl-Xl and YFP-Bax,followed with 120 mJ/cm2 UV irradiation. We found that the FRET intensity of GFP-PUMA and YFP-Bcl-Xl increased while the FRET intensity of CFP-Bcl-Xl and YFP-Bax dicreased suggesting PUMA has a more strong interaction with Bcl-Xl than Bax. At the same time,GFP-Bax translocated to the mitochondria from the cytosol in typical cells started at about 7 h after UV irradiation. Taken together,the results indicated that PUMA promotes Bax translocation by competitive binding to Bcl-Xl during UV-induced apoptosis.

Based on the characteristics of both amplitude distribution and phase distribution in cell′s scattering,which is based on the optical characteristics of three models they are sphere;nuclear and disc-type models for red blood cells (RBC). Considering the actual optical characteristics of cells,the light scattering theory and optical virtual simulation technology are applied. The results show that the scattering hologram of cells,especially the phase distributing properties,is closely related with the cell morphology. In other words,the phase distributing properties can resolve the cell morphology. Therefore,the cells can be directly recognized and sorted by the phase distributing properties and cann′t need for patterns reconstruction of cells three-dimensional.

Wheat seedlings were exposed to He-Ne laser irradiation (5 mW·mm-2 power density),enhanced ultraviolet-B (UV-B) radiation (10.08 kJ·m-2·d-1),and the combination of He-Ne laser irradiation and enhanced UV-B radiation for 5 days. Changes of DNase activity and RNase activity in the leaves and roots of wheat seadlings were measured to test the potential reparative role of He-Ne laser irradiation. The results show that exposing the seedlings to UV-B radiation results in the increase of the nuclease activity of the leaves and roots. The electrophoresis pattern of nuclease shows that enzyme spectrum zones do not increase,whereas enzyme activity increases. After irradiating by UV-B and the He-Ne laser,the nuclease activity of the leaves and roots becomes is lower than their activity under UV-B radiation alone. The electrophoresis pattern of nuclease also shows that enzyme spectrum zones do not decrease,whereas enzyme activity decreases. The results suggest that damage,induced by enhanced UV-B radiation on wheat seedlings,which affects the activity of nuclease in leaves and roots,can be repaired partially by He-Ne laser irradiation.

The experiment was to avoid cruor on the surface of the mechanical heart valve. Firstly diamond-like carbon (DLC) films were deposited on the mechanical heart valve,Al2O3,316 L stainless steel and silicon substrates by the pulsed laser deposition (PLD) at same experiment condition. The result demonstrated that diamond-like carbon film exhibited the best adhesion to the mechanical heart valve. Secondly the structure and composition and topography of diamond-like carbon film on the mechanical heart valve were measured by the visible Raman spectroscopy and the X-ray photoelectron spectroscopy (XPS) and the atomic force microscopy (AFM). Finally human umbilical cord vein endothelial cells (HUVEC) were seeded on diamond-like carbon film on the mechanical heart valve and cultured in vitro. Raman spectroscopy revealed that disorder peak was at 1341.66 cm－1and graphite peak was at 1528.17 cm－1. XPS spectroscopy revealed that there was 21.45% of sp3 in the film. AFM revealed that the roughness average of the film was 26.4 nm. Human umbilical cord vein endothelial cells could proliferate on diamond-like carbon film very well. The result demonstrated that diamond-like carbon film on the mechanical heart valve deposited by pulsed laser deposition had good cell compatibility and could be covered with human umbilical cord vein endothelial cells fully so that it is possible to avoid cruor on the surface of the mechanical heart valve.

In order to improve detection speed and classification precision of biological cells. Several typical blood cells’s optical phase models are set up based on the analysis of their optical characteristics and physical structures. The VirtualLab imitation system is applied to design relevant modules,and the phase distributions of these blood cells are gaired. A fast and accurate identification method is proposed after unwrapping and smoothing of the phase.

The purpose is to assess the the feasibility of femtosecond laser application in deep lamellar cut in rabbit corneas,search for the suitable parameter,and to evaluate the laser′s effectiveness through edema corneas. The sample was put on a three-axis translation stage which was under the control of concentrically ringed program,femtosecond laser (800 nm/50 fs) with different pulse energies was applied to focus on the rabbit corneas.The laser focused on the deep lamellar and produced dissection through the corneas along with the movement of the stage. After the lamellar interface cut,the corneal cut surface was examined by light microscopy and scanning electron microscopy(SEM).The corneas operated by using surgical instruments were used as controls. With the pulse energy of 4.4 μJ and the translation stage speed of 200 μm/s,the laser produced an effective and smooth dissection. While with the energy of 6.4 μJ at the speed of 300 μm/s,the laser made an effective and smooth dissection. Compared with the controls ,the experimental groups were better. The laser could also successfully created a smooth cut at the deepness of 400 μm on the edema cornea at the speed of 200 μm/s and the energy of 6.4 μJ.

The enhance effects of single-walled carbon nanotubes (SWNT) during photothermal therapy in 980 nm region in vitro and in vivo are studied. For in vitro study,the control group was not treated,the SWNT group was incubated with SWNT for 2 h,the laser group was irradiated with 980 nm laser,the laser+SWNT group were incubated with SWNT for 2 h and then irradiated with 980 nm laser. Cell cytotoxicity was assessed with CCK8 at 12 h after treatment. For in vivo study,the control group was not treated,the SWNT group was injected with SWNT,the laser group was irradiated with 980 nm laser,the laser+SWNT group were injected with SWNT and irradiated with 980 nm laser 6 h after injection.The destroy effects,tumor growth,survival rate between four groups were compard. The results show that compared to laser group,the laser+SWNT group could destruct the tumors significantly inhibit tumor growth effectively,and improve survival rate of mice. It indicates that SWNT could significantly enhance the photothermal therapy in 980 nm region.

A novel photo-thermal model of selective photothermolysis (SP) was proposed by using an element-based 3D Monte Carlo method to simulate the laser transport in the tissue,a 3D Pennes bio-heat transfer equation with variable thermal properties and dynamic changing vaporization temperature to calculate the temperature distribution,and the Arrhenius equation to predict the thermal damage. It was shown that the numerical results are significantly affected by the trapped vaporization coefficient k. The results obtained with k=0,0.022,0.18 and 1 of this model are close to those obtained with constant 100 ℃,110 ℃ and 130 ℃ vaporization temperature and without vaporization of the SP model,respectively.

To evaluate the efficacy and safety of photoselective vaporization of the prostate (PVP) for the treatment of benign prostatic hyperplasia (BPH),total 24 patients (mean age of 71.00±9.74 years) with BPH underwent PVP in our hospital by using Realton 100 W surgical green laser system. Prostate size,operation time,blood loss during operation,catheterization time and hospital stay were recorded. International prostate symptom score (I-PSS),maximum flow rate (Qmax),post void residual urine (PVR) were compared to the baseline. The results show that PVP is a safe and effective treatment for BPH,especially suitable for aged,high-risk or anticoagulant therapy patients. PVP has less bleeding during operation,shorter catheterization time and hospital stay．More follow-ups are needed to evaluate its long-term efficiency.

Cryogen spray is an effective cooling technique for the laser treatment of port wine stain (PWS),which can protect the epidermis from the thermal injuries safely. However,cryogen R134a cannot supply enough cooling capacity for the laser surgery in patients with darker skin because of the absorption of laser energy by melanin. Cryogen R404a are expected to protect the darker skin well because of its lower boiling point. A theoretical model is proposed to describe the evaporation process of single droplet and its validation is confirmed by the agreement between numerical simulation with experimental result. With this model,the cooling effect of R404a droplet is compared with R134a droplet and it is found that R404a droplet can reach lower temperature. Then the influences of initial diameter and ambient mass faction of cryogen on the evaporation characteristics of R404a droplet are analyzed and the result is useful to guide the cryogen spray cooling for laser therapy of PWS patients with darker skin.

Total 60 patients who are of stage T1 and T2 transitional bladder cancer by cystoscopic examination and consequent biopsy separated are into three groups for each treatment. Photodynamic therapy (PDT) groups include group A and B which consist of 17 and 15 patients,respectively,while a controlled group has 28 patients. The PDT groups don′t have PDT until they have oral administration of CDHS801 (200 mg/50 kg) before 24 h. Then,all of them received regional irradiation using semiconductor laser at wavelength of 650 nm,with a power density of 50 J/cm2. 72 h later,transurethral resection of bladder tumor (TURBT) was performed without sunlight avoiding step for the purpose of obtaining tumor sample and further pathological analysis. The controlled group were performed routine TURBT. All the patients received intravesical chemotherapy routinely after TURBT,except for the patients in group A. The comparison criteria include of five-year survival rate,quality of life,tumor recurrence and tumor progression. The results show,patients in group A have better response of the question of quality of life than those in group B or controlled group (P<0.05). Both group A and B incidence of tumor recurrence is lower than that of the controlled group (P<0.05),but there is no significant difference of five-year survival rate and tumor progression rate among these three groups. As an assistant therapy of TURBT,photodynamic therapy may be a better alternative than intravesical chemotherapy for it is of more efficacy and safety on the treatment of T1and T2 transitional bladder caner.

To discuss the effects of photodynamic therapy (PDT) on the mainly oral cariogenic biofilm bacteria,an artificial caries model was built consistent with the physiological environment with streptococcus mutans. Hematoporyrin monomethyl ether was selected for photosensitizer. 635 nm diode laser was used for irradiation,with delivered power 10 mW and energy density 12.47 J/cm2. Fifty enamel blocks were formed artificial caries models. Separated them into five groups random,ten blocks each group:1) Group of HMME;2) Group of laser;3) Group of PDT;4) Positive control group of 0.05% chlorhexidine;and 5) Negative control group of 0.9% saline. The influence of on dental plaque oral biofilm of artificial dental caries was observed according to plate counting of bacteria method. Compared to negative control group,the number of streptococcus mutans (CFU/mL) of oral biofilm in artificial caries model of HMME group was not significant different (P>0.05),with the bactericidal rate only 0.05%;laser irradiation and 0.05% chlorhexidine made the number of streptococcus mutans of oral biofilm in artificial caries model significantly reduced (P<0.05),with the bactericidal rate 59.94% and 58.52% separately;after PDT treatment against dental caries,the number of streptococcus mutans of oral biofilm in artificial caries model significantly reduced (P<0.05),the bactericidal rate up to 99.36%. HMME-PDT is an effective method in eliminate streptococcus mutans of oral biofilm for artificial caries model. It provides an new effective approach for dental caries prevention.

Aim to explore a potential treatment of AIDS-photodynamic therapy by detecting the photoinaction on hunman immunodeficiency virus (HIV) in vitro,mixed the photosensitizes hematoporphyrin monomethyl ether or methylene blue by a series of dilute strengths with the host cells MT4,C8166 or H9/HIV-1ⅢB or the virus HIV-1ⅢB for 2 hours incubation,followed by irradiation by a 630 nm semiconductor laser with energy density 0.3 J/cm2. After certain time,the activites against HIV-1ⅢB were assayed by determining the syncytial formation under the inverted microscope or MTT and measuring the p24 antigen expression level in supernatant by ELISA. Results show PDT inhibited the cell-cell fusion (inhibition rate,HMME-PDT64.68%,MB-PDT61.56%)and virus-cell fusion (inhibition rate,HMME-PDT 85%,MB-PDT 73.64% )induced by HIV-1ⅢB significantly,and had an intensive inactivation on the cell-free HIV-1ⅢB especially the inhibition rate up to 100%. However,PDT had no effect on the replication course 2 hours after cute infection or chronic infection of HIV-1ⅢB. Therefor PDT has outstanding inhibition on cell-free HIV-1ⅢB and fusion induced by HIV-1ⅢB,which prompts PDT may be a new treatment of AIDS in future.

One limitation of the single-stage acousto-optic tunable filter (AOTF) as a bandpass filter is the presence of large sidelobes higher than -9 dB. Multi-stage AOTF for suppressing sidelobes further is studied in this paper. The filter characteristics of single and multi-stage AOTF have been analyzed and compared theoretically and experimentally,and the advantages of multi-stage filters have been demonstrated. First the theory of single-stage collinear and quasi-collinear AOTF were discussed,and then the transfer function of multi-stage filter was obtained. The calculations have shown that multi-stage devices can provide significant improvement not only in sidelobe suppression but also in bandwidth narrowing as compared to single-stage ones. The triple-stage AOTF was measured,and a sidelobe suppression of about -27 dB and a narrower bandwidth were obtained. The experimental results demonstrate multi-stage AOTF is of lower sidelobe and narrower bandwidth.

Using the accurate expression of the Voigt profile we obtained,a method for the calculation of the optical depth of laser produced plasma is given out. Taking the magnesium laser produced plasma as an example,the optical depth,and the escape probability of magnesium laser produced plasma based on the optical depth are calculated,and the calculation results are in agreed with the experimental results. Finally,we point out a method to calculate the resonance escape factor of laser produced plasma using the optical depth.

Multiphysics finite element analysis was used to simulate the heat distribution in a optical pumping semiconductor vertical-external-cavity surface-emitting laser (OPS-VECSEL). Specially,the VECSEL with a plate of transparent diamond that capillary bond to on cap layer of chip was calculated. Calculation indicate that when there is no diamond piece,the temperature difference between first and the last quantum well is about 150 K. But when the cooler is present,the temperature difference between them is very small as well as the resonale wavelongth difference. In addition to diamond piece,a silicon microchannel cooler soldered onto DBR side of chip ulteriorly decreases the temperature difference between quantum wells and optimizes character of the chip. Simulating calculation also shows that properly increasing the diameter of pumping optical speckle was obviously able to lower the thermal effect,specially the heat lens effect.

A novel method to realize time-sharing multiple optical traps is reported. Adding a tilted glass plate to the optical path,the laser propagation direction translates slightly. The dependence of trap position relying on the geometrical parameters of glass plate,such as plate site,thickness and tilted angle,are analyzed. A turnplate which is capable of loading as many as 8 glass plates of different thicknesses has been designed and fabricated. A direct current motor rotates the turnplate enabling mechanical chop of the laser beam,which forms the time-sharing multiple optical traps. Two and three polystyrene beads with different sizes are trapped by timing-sharing dual optical traps and tri-optical traps respectively. The distance between two adjacent traps varies when changing the tilted angle of the glass plate. Experimental results agree well with our theoretical ones discussed in the paper.

The channel of free space optical communication (FSO) has to experience varied channel effects such as dust,rain,fog etc. The system which simple combined FSO with orthogonal frequency devision muitiplexing (OFDM) is more complicated although OFDM can resist the influence of scatter. We proposed a new time frequency code to solve the shortcoming of the traditional FSO-OFDM system. We established the channel model according to the characters of atmospheric channel. And particular described the compilation method of time frequency code and analyzed the relation between the system′s bit error rate (BER) and the channel characteristic after introducing the FSO-OFDM system model. At last,this scheme is confirmed by Monte Carlo approach. It is shown that this method not only can simplify the system but also can improve the error rate performance of the system effectively.

Thermal aberrations are introduced into the amplified laser beam in power amplifier of a master oscillator power amplifier (MOPA) solid state laser system and degrade the beam quality. Adaptive optics (AO) system can be used to compensate for the wavefront aberrations in real time to improve the beam quality. An optimization-type adaptive optics system with the iteration rate of 100 Hz was built up. In this system,a 37-element deformable mirror is controlled by the stochastic parallel gradient descent (SPGD) algorithm with the power-in-bucket of the far-field laser beam as the metric,which is measured by a photoelectric detector. The beam cleanup experiments were performed by the SPGD AO system for the MOPA laser system comprised of Nd:YAG master oscillator and Nd:YAG power amplifier at different pumping currents. The results show that the beam quality is improved in all cases,and even for the beam with a beam quality of β>9,the β factor is decreased by 58% after cleanup. It is indicated that adaptive optics based on stochastic parallel gradient descent algorithm can be used to beam cleanup.

In order to explore the feasibility of fabricating prosthetic ear with selective laser sintering method,layer-milled graphic technique is used to acquire the data of left ear. A 3-D digital model of left ear is produced. A digital model of right ear is produced by mirror imaging. Selective laser sintering (SLS) and wax powder PCP1 are chosen to fabricate a wax right ear model. The skin texture and pore are sculped on the wax model and the prosthetic ear is made by silicone elastomer. The result shows that the right ear wax model is not only distinct and precise,but also can be replaced by silicone elastomer directly. This study suggests that SLS and the new wax powder PCP1 can be used to fabricate prosthetic ear. Comparing with conventional manual methods,the new fabricating method shortens time and simplifies manufacturing steps. This digital and model-free manufacture provide can a new method for the automatic manufacture of maxillofacial prostheses,and will lay the foundation for the clinical application in the future.

The method of statistics factorial experiment was applied on the experiment. X-ray diffraction (XRD) was used to characterize the phases in coatings. Proper technologic parameters were found by evaluating the effect of technologic parameters of laser rapid forming on phases of bioceramic coatings .The results showed that CaO and CaTiO3 were obtained with high laser power,while Ca3 (PO4)2(TCP) was obtained with low laser power. Laser power can not only affect the quantity of the phases in the coatings,but also their kinds. TCP was also obtained at high scanning velocity,while CaO and CaTiO3 were obtained at low scanning velocity. The scanning velocity can only affect the quantity of the phases in the coatings. When the laser power was 800 W and the scanning velocity was 500 mm/min,bioceramic coatings with more TCP can be obtained.

In order to overcome the difficulties of laser melt injection (LMI) on aluminium alloys,including high reflection of laser,oxide film and high heat conductivity,laser-tungsten inert gas (TIG) hybrid melt injection was exploited. The influence of process parameters,including the mode of hybrid laser-TIG,feeding powder type,the carrier gas flow,the shield gas flow of TIG,laser power and TIG current,were investigated. The results show that,in order to achieve appropriate surface enhancement effect,the powder should be fed from back side of laser beam. With the increase of TIG current,the depth of LMI layer increases monotonously. With the increase of laser power,the depth of LMI layer increases firstly and then decreases. The carrier gas flow and gas flow of TIG are the key factors which influence the LMI process,and should be matched and selected. Through optimization of process parameters,WCp/Al layer was prepared successfully on the surface of aluminium and the LMI layer with different thickness ranging from 0.5 to 4.3 mm can be achieved.

The pullulation ratio of the soybean,the content of the isoflavone for the cotyledon and laminae,and the mean height of the soybean seedling affected by a frequency doubled Nd:YAG 532 nm laser for different power density and time are presented in this paper. The mechanism is discussed from the activity of a phenylalanine ammonia-lyase (PAL) as an initial enzyme for synthesizing the isoflavone and the efficiency of the photosynthesis. The results show that the activity of the PAL and the products of the photosynthesis such as the soluble sugar,the sucrose,and the amylum are all increased after the soybean seed being irradiated by laser,in which the best result is occurred at 15 mW/mm2 of laser for 5 mins. At the same time,the efficiency of the photosynthesis of the soybean seedling is increased,which promotes the enormous accumulation of the isoflavone.

High-speed swept source based on optical frequency-domain imaging is a new generation of optical coherence tomography (OCT). It is one of the hot topics in area of OCT and biomedical optical imaging due to its superiorities in speed and sensitivity over traditional time-domain technique. This paper summarizes current status and advances achieved in high-speed swept laser source. Technologies and applications of the swept laser source based optical frequency-domain imaging are introduced. Existing issues and future trends are also discussed.

In this paper,theoretical and technical development of coherent anti-Stokes Raman scattering (CARS) microscopy is reviewed. The requirements of CARS microscopy on the pump laser source and typical experimental instrumentation are discussed and compared. We investigate the non-resonance background noise which is the most critical problem and can not be avoided in the CARS microscopy. Different methods for suppressing non-resonant background noise are presented and compared. Finally,a brief analysis of existing problems in CARS microscopy and possible solutions is presented.

Function-specific homeostasis (FSH) is a negative-feedback response of a biosystem to maintain the function-specific conditions inside the biosystem so that the function is perfectly performed. Low level light (LLL) is so defined that it can not modulate the function in its FSH,but it can modulate the function far from its FSH. FSH quality is represented by function complexity and FSH stability. The FSH stability is maintained by longevity factors which mediate longevity extension. The function complexity and FSH stability are specific with each other so that there is FSH-specific longevity factor activity for each one. Among the longevity factors,sirtuins (SIRTs) are the most famous family. There is FSH-specific SIRT activities (FSSA). The FSSA increase as the FSH quality goes up. For the cells which SIRT activities are lower than FSSA,LLL may increase SIRT activities until the SIRT activities arrive at FSSA,respectively. For the cells which SIRT activities are higher than FSSA,respectively,but they can be back in FSH,LLL may increase the SIRT activities of the other cells,which promotes the rehabilitation of the cells so that they may be back in FSH. For the cells which SIRT activities are much higher than FSSA,respectively,LLL may promote the establishment of a new FSH of higher FSSA. In summary,the cellular optical rehabilitation may be mediated by SIRTs.

In order to analyze experimentally the back-scattering micro-spectrum difference between human normal stomach epithetic cell and the cancerous cell to provide optical technique for clinical checking,a micro-spectral measurement setup for checking cell was established based on fiber confocal microscopically imaging technique combined with cell light scattering theory. It could provide micro-imaging and micro-medical spectral information simultaneously. Adherent monolayer human normal gastric epithelium line GES-1 and human carcinoma cell line NCI-N87 were measured with the setup respectively. The spectral results illuminated that micro-back-scattering intensity from NCI-N87 cells was stronger than that from GES-1 in 500-800 nm range,and GES-1’s scattering spectrum showed a regular intensity change but NCI-N87’s didn’t. It indicates that fiber confocal back scattering (FCBS spectrometer) micro-spectral measurement system established can distinguish normal from dyplastic cell at cellular level. The experimental results agree well with theoretical expecting results from literature. Understanding the cell scattering properties of different pathological phases will aid in the development of noninvasive optical techniques for detection of precancerous conditions.

We explored the mechanism of gene damaged by Auger electron using the Raman spectroscopy. The primers of the gene of alpha fetoprotein were labeled with radioactive iodine-125,and combined the gene of alpha fetoprotein. After the Auger electron emitted from iodine-125 radiated on gene two hours,the Raman spectroscopy was applied to investigate the influence of Auger electron to the biogenic conformation and functional groups in aqueous solution,with 514.5 nm excitation. The results show that the peak of the characteristic Raman spectra moves and the peak intensity changes with the Auger electron radiation from 2 hours to 24 hours. The change of Raman spectra indicates that the construction of the phosphodiester linkage harmed,the pyridine and purine bases in DNA emerged and damaged,the model of gene conformation changed from B form to C form spectrum. In conclusion,the Auger electron closely radiation may change the construction of backbone of DNA,destroy local pyridine and purine bases in DNA,and change the conformation of gene.

Inhibit angiogenesis is one of important tumor therapies. If the mechanism of vascular changes can be detected from molecular lever,it will have therapeutic significance. Raman spectroscopy is a non-destructive spectrum technology holding rich information,which can be applied to the structural analysis of solid,liquid or solution of biological molecules. Based on confocal Raman microscope,a unique system is developed for obtaining the different Raman spectrum about vessels of the chick embryo with and without the anti-angiogenic drugs-thalidomide. In the study,the location and shape of the average Raman spectrum of vessels in drug 5 h is similar to the ones without medicine,but the intensity of some characteristic peaks changes. Intensity at 1441 cm-1,1527 cm-1and 1657 cm-1,increases markedly,while the 971 cm-1 and 1081 cm-1 decreases. The change is due to vascular medicine which causes the nucleic acid,protein,phospholipids and other important biological molecules in the vessels to change on the structure or content.The result indicates that Raman spectroscopy could be an effective tool for detection of the mechanism of vascular changes.

Hemoglobin (Hb) bart′s hydrops is caused by mutations or deletions affecting all four α-globin genes,leading to absent α-globin chain production from the affected genes. Laser tweezers Raman spectroscopy (LTRS) is a useful tool for single-cell analysis based on the optical trapping and Raman scattering. A LTRS setup with 785 nm laser beam was used to record the Raman scattering of trapped single erythrocytes from Hb bart′s hydrops. The results reveal that the Hb bart′s erythrocytes are possessed of not only diversiform cells and heterogeneous Raman scattering signals,but remarkable low intensity of Raman scattering and definite proportion nucleated erythrocytes,while the normal controls homogeneous. The analyse of Raman spectra and principal component analysis uncovers the Raman scattering heterogeneity of cells with normal shape and middle size. LTRS peeks insight into the abnormal biochemical essence beyond the normal cell appearance due to the heme aggregation and protein denaturalization.

The fabrication of silver nanoarchitectures (Ag nanofilms) on glass substrates by using a low-cost electrochemical strategy at a proper voltage and polyvinyl alcohol concentration in electrolyte is reported. Ag nanofilms are grown and built with nanoblocks of two-dimensional spherelike nanostructures,which show a highly active and stable surface enhanced Raman scattering (SERS) effect. It shows that the average particle size of silver nanoparticles on the surface of the Ag nanofilms is about 200 nm,and the average size of the nanoblocks is also about 200 nm. The SERS spectra of the human sera for 20 healthy donors were studied on a portable Raman spectrometer,meanwhile,SERS spectra of the serum for the same person was also detected based on different Ag nanofilms prepared with the same conditions. The results show that the SERS effect of human serum is perfect based on the SERS substrate,which will provide a potential tool for analyzing human serum.

405 nm LED was chosen as excitation source,Rose Bengal (RB) was used as photosensitizer,early oral tumor can be detected. Normal oral mucosa can not be dryed by Rose Bengal,oral precancerous lesions or tumors can be dryed by RB. It is known that characteristic fluorescence spectroscopy of lesions which were dryed ranged from 560 nm to 600 nm through spectral measurement,however normal oral cavity has special fluorescence peak around 480 nm. When precancerous lesions become malignant tumor,the special fluorescence spectroscopy was changed. Typical fluorescence peaks of porphyrin appeared at 630 nm and 690 nm. Combined with the technology of light induced fluorescence and the method of fluorescence ratio,oral precancerous lesions can be diagnosed,the sensitivity and specificity can arrive 95% and 92.5%. This is a non-invasive,quick and early diagnosis method. It increases survival rate of oral cancer patients remarkably.

The atherosclerotic plaque and vessel wall are experimental studied by laser-induced fluorescence spectroscopy (LIFS) and Raman spectroscopy in order to provide a real-time monitoring for laser angioplasty. Fifteen male Japanese white rabbits fed three months with high-fat feed get aortic arch and do portrait incision by using 380 nm ultraviolet (UV) laser and 532 nm green laser as light source to induce fluorescence spectroscopy of atherosclerotic plaque and vessel wall respectively,while 532 nm green laser is used as light source to induce Raman spectroscopy. Results shows that,380 nm UV laser-induced fluorescence spectra of atherosclerotic plaque and vessel wall both have characteristic peaks at wavelength of 416 nm,but the intensity of the former is significantly higher than the latter;532 nm green laser-induced fluorescence spectra both have characteristic peaks at wavelength of 800 nm,but have no significant difference in intensity;The Raman spectroscopy of atherosclerotic plaque has one peak at wavelength of 3000 nm and one trough at 3300 nm,but the Raman spectroscopy of vessel wall is smooth without any peaks. Therefore,both 380 nm UV laser-induced fluorescence spectroscopy and Raman spectroscopy can effectively differentiate atherosclerotic plaque and vessel wall,while 532 nm green laser-induced fluorescence spectra cannot differentiate them effectively.