In order to remarkably improve the spatial resolution of the fused multispectral images and preserve the original multispectral characteristics as much as possible, a selective remote sensing image fusion method is proposed based on the local feature of contourlet coefficients. Firstly, a window neighborhood mobile template is used to calculate the different local features of corresponding contourlet coefficient matrix one by one for the approximate components and the detail components of each direction of each layer resulting from contourlet transform according to the different fusion purposes of low and high frequency parts in the fusion process of multi-spectral and panchromatic images. Then the approximate images and detail images are fused selectively in contourlet coefficients domain by applying different fusion rules based on proper criterion. The resultant image with high resolution and multi-spectral characteristics is obtained by inverse contourlet transform and inverse intensity-hue-saturation (IHS) transform. Landsat TM and SPOT images are used to conduct the fusion experiment and the results show that the proposed algorithm can remarkably enhance the spatial details and well preserve the spectral features of the original images. This algorithm performs better than traditional fusion methods.

In order to obtain clear restoration result from a blurred image, we propose the frog leaping algorithm. The frog population is divided into several groups, each ethnic group includes a number of frogs, and every evolution only updates the worst frog′s position. In order to prevent the solution space from contraction, the best individual is chosen to perform operation with the Gaussian mutation operator. A threshold value strategy is set to guide the update of the variables in various dimensions of frog leaping. The blurred image restoration model is established, in which the relation between blurred and restored images is set up with the nonlinear mapping characteristics of the frog leaping algorithm. The blurred image restoration solution converges on the Poisson statistical maximum likelihood solution. A recovery evaluation system is established. Simulation results show that the frog leaping outperforms other algorithms with the clearer recovery, the highest improvement percentage and the least time consumption.

In order to improve the detecting precision and robustness in determination of the content of nicotine in tobacco by near infrared spectroscopy, a predictive model is established by genetic algorithm combined least square support vector regression (GA-LSSVR). The practical use of support vector machine is limited because of its set of parameters to be defined by the user. For this reason, a genetic algorithm is utilized to approach LSSVR parameter optimization in the calibration model. To highlight the superiority of GA-LSSVR algorithm, it is compared with traditional LSSVR and genetic algorithm-partial least square. The correlation coefficient R2 and root mean square error of prediction (RMSEP) for the test set are used as evaluation parameters for the model. The optimal model is obtained with R2 of 0.9766 and RMSEP of 0.1065. Generally, in the context of performance and robustness, the results demonstrate that GA-LSSVR is a good method for the analysis and modelling of near infrared data.

The method for measuring refractive index of micro-quantity liquid within a glass capillary has a promising application in virtue of minimal sample requirement and confinement of liquid in a capillary. In order to improve the measurement uncertainty and convenience, the traditional eyepiece is substituted by a CCD-containing electronic eyepiece. In addition, an electric precision displacement stage is used instead of the traditional manual precision displacement stage. Refractive indices of solutions of glycol with various concentrations are measured by the new measurement system in our experiment. The measurement uncertainty reaches to ±0.0002 and the required liquid quantity is less than 0.002 mL for a single measurement. In the method for measuring refractive index of micro-quantity liquid within a glass capillary, the introduction of electronic eyepiece and electric displacement stage improves the uncertainty of the measurement.

A new method to detect and correct the phase errors of laser arrays is presented. This method, based on finding the brightest point of the diffraction pattern, can be used to detect both piston errors and tilt errors. The principle of this method is described theoretically. A system combining two laser beam arrays is built based on active segmented mirrors to testify the efficiency of the method. The experimental results show that the root-mean-square (RMS) value of the piston errors can be controlled in λ/19 and the tilt errors can be controlled in 25 μrad (0.5 times of the diffraction limit). The experiments prove that the new method can be used to detect the phase errors in coherent beam combing of laser arrays.

A laser diode end-pumped Nd:YVO4 picosecond regenerative amplifier with the repetition rate of 1 kHz is demonstrated. At the pumping power of 20 W and pumping pulse width of 100 μs, a stable output power of 1.5 W is obtained with the extraction efficiency of 7.5%. The pulse width is measured to be about 15 ps, and the beam quality factors M2 in both directions are less than 1.4.

Abnormal discharge of laser resonator is studied by using the NEL-A series high-power fast-flow axis CO2 laser. By chemical experiment, it is verified that the main corrosion of laser resonator is the basic carbonate copper. Based on physics and chemistry theory, the causes of basic carbonate copper and the micro-mechanism of abnormal discharge of laser resonator are analyzed. The testing results show that the basic carbonate copper is the main reason of abnormal discharge. The conclusion can be used as a reference to improve the design of laser resonator and gas supply unit. At the same time, it provides a new way for equipment maintenance on the spot.

Difference frequency generation is an important method to obtain 3~5 μm mid-infrared laser. It does not need complex structure adjustment of cavity, the tuning range of output laser is wide, and the efficiency is high. We derive the formulas of output wavelength, linewidth and output power of the mid-infrared laser obtained from difference frequency generation. The dependences of output linewidth on pump light wavelength, pump light linewidth, signal light linewidth and temperature are emphasized. Numerical results show that the output linewidth is mainly decided by the pump light linewidth and the signal light linewidth.

A high precision north finder based on rate biased ring laser gyro (RLG) is designed. The north finder is constituted by the 90-type RLG and a high precision one-axis rotation platform. The north finding experiment is realized by using two-position sampling scheme. To weaken the effect of quantification error, moving average method has been carried out. The experiment is carried out at the geography latitude of 28.2°. It is shown that the precision of north finder on stationary base is better than 16″ after 200 s.

Defocusing phenomenon induced by the change of the work distance in the irradiating process of biological tissue has an important influence on the effect of hard tissue ablation with pulsed lasers. Fresh bovine shank bone in vitro used in the experiment is put on a computer-controlled motorized linear drive stage and is moved repeatedly with the speed of 5.5 mm/s. A parallel beam of pulsed CO2 laser passes through a mobile focus lens and irradiates the sample surface vertically. Through changing the position of focusing lens, the focus position is altered and dynamic focusing is realized. The laser wavelength is 10.64 μm, the power is 6 W, the pulse repetition rate is 420 Hz, the spot size is about 200 μm, and the water spraying with a speed of 5.5 mL/min is used. The surface morphology and microstructure of ablation grooves are examined by scanning electron microscope (SEM). The crater depth is measured with optical coherence tomography (OCT). The results show that compared with defocusing condition, dynamic focusing condition can enhance the ablation rate and produce more irregular surface morphology and microstructure. The ablation depth increases with the increase of equivalent pulse number and the ablation rate decreases.

There exist misdiagnosis and missed diagnosis with routine ultrasound imaging of thyroid nodules in present clinic. A novel method employing a series of long-focal-zone focused transducers with different frequencies for photoacoustic imaging (PAI) is presented. Some blood clots in different sizes are embedded in tissue-mimicking phantom to form a phantom containing specific pathological lesions. Transducers with different frequencies are used to image this phantom photoacoustically. Furthermore, blood is injected into normal human thyroid tissue, forming two blood stasis areas. Three-dimensional imaging is available by performing two-dimensional scanning through the tissue. We demonstrate that transducers with different frequencies have different sensitivities in detecting lesions of different sizes. The broadband transducer with a center frequency of 5 MHz has a better sensitivity in detecting lesions ranging from a few hundred microns to several millimeters. Therefore, a high resolution and excellent contrast three-dimensional image of the thyroid tissue with two blood stasis areas is obtained. This technique integrated with ultrasound imaging has the potential to increase the diagnostic accuracy in clinical thyroid nodule diagnosis.

Two-photon fluorescence imaging technology has several outstanding characteristics, including lower photon-bleaching and photo-damaging, high contrast and longer penetrating distance. An acute myocardial ischemia model of rat is established by the ligation of the left anterior descending branch. Then fluorescence images of the front wall of left ventricle at different ligation time are attained by two-photon fluorescence imaging. The morphologic change of myocardial ischemia tissue was obtained and a primary evaluation of the damage degree of myocardial tissue is obtained by fast Fourier transform (FFT) with an orientation index. The result indicates that the two-photon fluorescence imaging technology combined with FFT has the potential to be used for the estimation of myocardial ischemia tissue range and assess of the damage degree of myocardial tissue rapidly and accurately in the diagnosis and therapy in real time.

The propagation properties of elliptical Hermite-Gaussian light beam in a strongly nonlocal nonlinear medium are studied. As the characteristic width of response function of strongly nonlocal media is much bigger than the beam width, the response function is expanded twice with Taylor series and the series are both preserved up to the second-orderterm, and the approximative Lagrangian density function corresponding to nonlocal nonlinear Schrdinger equation is thus obtained. Based on this, the evolution equations, evolution laws of elliptical Hermite-Gaussian light beam′s every variable and two critical powers are also derived using variational method. When the ellipticities of light beam and response function satisfy certain conditions, these two critical powers are equal. When the initial power is equal to the critical power and light beam is incident at the beam waist, the elliptical Hermite-Gaussian spatial optical soliton is obtained. Further studies point out that the phase shift of elliptical Hermite-Gaussian spatial optical soliton is closely connected with media′s ellipticity and soliton′s order. With different values of the media′s ellipticity and soliton′s order, large positive, zero even negative phase shift may come into being.

Cassegrain system is the most classic reflective optical system in telescope systems. The imaging point of a regular Cassegrain system is outside the system and thus can be tested using an interferometer. However, the imaging point of the improved Cassegrain system lies between two mirrors, so that it cannot be directly measured. It can be tested in two steps based on the system characteristics: an accurate test is made for the primary mirror; the image quality is evaluated based on the system′s dispersion spot. Such a system is measured by a profilometer and tested by Zygo interferometer and the optical shadow method. A special structure is used to test accurately. The surface figure should be modified based on the measured results in the test process to meet the requirements on the optical system′s imaging quality.

The polishing mechanism of silicon carbide optical surface still remains untouched. This paper studies the polishing mechanism of silicon carbide optical surface; it also introduces the grinding mechanism of ceramic materialindentation fracture model. The model of silicon carbide polishing in ideal condition is analyzed and the mechanism of silicon carbide polishing in real state is studied.

A compact collimator for light-emitting diode (LED) source is designed. The collimator is a catadioptric rotational system. The refraction part is used to collimate the rays with small view angle, and the reflection part is used to collimate the rays with large view angle. The design results are verified by optical simulation software TracePro. The results show that the divergence angle can be reduced to about 4° from 70° by the collimator with the optical efficiency of 85%. The height and diameter of the system are 7.65 mm and 8.73 mm, respectively. The optimal separation angle range is 41°～45°, and the optimal proportion factor range of refraction angle is 0.4～0.5.

In this paper, we demonstrate a top-illuminated InGaAs pin photodetector grown on InP substrate. The fabrication, measurement and characterization of this photodetector are discussed in this paper. Low dark current densities of 1.37×10-5 A/cm2 at 0 and 93×10-5 A/cm2 at a reverse bias of 5 V are achieved. At a wavelength of 1.55 μm, the photodetectors have a responsivity of 0.61 A/W without antireflection coating, a linear photoresponse up to 28 mW optical power and a maximum linear photocurrent of 17 mA at -3 V. The measured 3 dB bandwidth of a 22 μm-diameter photodetector is 17.5 GHz.

The controlling card for light-emitting diode (LED) display screen is designed based on LPC1300 universal serial bus (USB) and USB device. From the content (including image and text) to be displayed, the host computer extracts the bitmap information. Lattice information is obtained by transforming the extracted information with an appropriate algorithm. Moreover, the host computer can set up relevant parameters of the controlling card, such as font size, font type, dynamic effects, and so on. The related information sent to the controlling card through USB. The controlling card reads and deals with the contents in the buffer,and drives the LED screen to display the contents.

The principle of surface plasmon resonance (SPR) sensor is introduced. A SPR measurement system with Kretschmann configuration is designed based on wavelength modulation technology. The relationship between refractive index and resonance wavelength for ten different concentrations of alcohol solution is measured by detecting the light intensity reflectivities with fixing the incident angle while changing the wavelength. Experimental results show that the resonance wavelength increases with increasing sample refractive index, exhibiting good linearity. The SPR sensor can realize the measurement of refractive index or concentration of unknown solution by analyzing the resonant spectrum. The SPR sensor demonstrated here is featured with compact structure, simple operation, accurate and real time measurement.

Focusing properties of the vortex beams with axicon is studied. The focusing intensity distribution of vortex beams with axicon by using Huygens-Fresnel diffractive integral is investigated. Numerical calculations show that after focused by the axicon, a vortex beam can convert into a high-order Bessel beam. The influence of by different cone angles of the axicon and the different topological number of the vortex beam on the focusing properties of vortex beam is investigated. The results show that in the maximum distance of the non-diffraction zone of the axicon, the obtained high-order Bessel beam keeps the original non-diffraction properties.

Photobiomodulation (PBM) is a biomodulation of laser irradiation (LI) or monochromatic light. The LI may be low intensity LI (LIL) at about 10 mW/cm2, moderate intensity LI (MIL) at 0.1~1.0 W/cm2 or high intensity LI. The progress in PBM studies is reviewed from homeostatic viewpoint in this paper. 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. FSH can resist internal or/and external disturbance under threshold, but can be disrupted by FSH-specific stress (FSS). There is a FSS-specific homeostasis (FSSH) in which a FSS not only disrupts the original FSH, but also establishes a new FSH so that it is called a successful stress. Low level LI (LLL) has been so defined that it cannot modulate a successful stress or a function in its FSH, but it can modulate a FSS far from its FSSH. LIL might be coordinately mediated by many kinds of proteins in membrane of cells or cellular organellae so that the FSH can be self-adaptively established. MIL might be mediated by endogenetic photosensitive proteins. LLL can be used to diagnose the process for a function to establish its FSH or for a FSS to establish its FSSH and the FSH or FSSH itself. The applications of PBM in enhanced recovery after surgery are also discussed.

We review the recent research of photonic crystal fiber Bragg grating and photonic crystal fiber grating lasers at home and abroad according to the process of development. The progress in theory and technique of grating formation is briefly introduced. The research status of narrow-linewidth single-frequency fiber grating lasers is emphasized, especially for the PCF grating lasers.

Pumping technology is a key factor to realize high power fiber laser. Various end-pumping technologies and side-pumping technologies, which are adopted in double-clad fiber laser at home and abroad, are introduced in detail. The advantages and disadvantages of these technologies are compared. The analysis shows that taper-fused bundle end-pumping and GTWave side-pumping are more propitious to achieve high power fiber laser.

The theory of photoacoustic (PA) imaging is introduced. The existing reconstrution methods, their foundmental and results at home and abroad are summarized. The filtered back-projection algorithm and the Fourier transform method based on acoustic lens, which can realize reconstruction of PA image from the PA signals recorded by ultrasonic sensors are both described. The demodulation of PA signals by optical systems is also introduced. In the optical methods, PA signals are modulated by probing optical beam and turned into optical signals, then it can be demodulated by different optical systems, and finally the sample image can be monitored by CCD camera dynamically. Comparison is made among the different real-time PA imaging methods and some new ideas are proposed.

Tm-doped fiber lasers have a huge applied prospect because of their emitting wavelength about 2 μm in the absorption of water molecules, eye safety and being considered to be effective pump sources for 3~5 μm optical parametric oscillator. This paper launches a series of studies on continuous wave laser, pulsed laser and tunable laser with imported and domestic Tm-doped double-clad fibers. Spectral characteristics of imported fiber are studied, with the maximum output power of 6 W and the slope efficiency of 50% for continuous-wave (CW) operation. For domestic fiber, the maximum output power is 5.1 W and the slope efficiency is 41.9%. A back-Littrow configuration is adopted with a blazed grating as a frequency selecting component. The maximum tunable range reaches 105 nm, and the linewidth of each laser spectrum is about 2.2 nm in the tunable range. A Q-switched fiber laser with an acousto-optic modulator (AOM) is also reported. The laser generates pulses of 200 ns duration with 840 μJ pulse energy, corresponding to the peak power of 4.2 kW when the repetition rate is 1 kHz. The shortest duration of 180 ns is obtained with the repetition rate being 3 kHz. Laser diode (LD) double-end pumped Tm-doped fiber laser is also studied. The effect of fiber length and transmission of output mirror on output power is analyzed. A red shift in the wavelength of the output with the increase of the pump power is also discussed.

In thin-film thickness wideband monitoring system based on merit function, because the measured spectrum curve deviates from the designed one, the merit function becomes divergence, which results in the failure of monitoring. Utilizing the thin-film transmittance spectrum curve measured, for the thin-film layer which has been deposited, its actual optical constants are fitted in real-time by simulated annealing algorithm to correct the merit function. Then the absorption effect of layers having been deposited on the layers to be deposited is compensated, and the layer number and thickness of the layers to be deposited are redesigned. The new merit function is achieved, by correction layer by layer. Experimental results show that the monitoring error of thin-film thickness may be less than 10-2, and the precision satisfies the practical requirement.