Computational fluid imaging (CFI) technology is an excellent tool for comparing numerical simulations with wind tunnel experiments of flow. Key methods including reconstruct computational fluid shadowgragh, schlieren and interferogram with numerical simulation technologies. Complex turbulence simulation, trilinear interpolation and flow image reconstruction etc. are developed. CFI technology is used for computational images reconstruction of the three-dimensional complex flow around an obstacle in the shock tube, and results are compared with those from bidirectional holographic experiments. It is shown that CFI can be used in reconstructing patterns of flows with complex geometric boundaries, the zonal area and unsteady characteristics etc., and it may be adopted not only for analyzing flowfield structures, but also for comparing numerical simulations with wind tunnel experimental results.

Backscattering coefficient is the source of information for remote sensors to acquire water information and it is also an important parameter of bio-optical model. The in-situ data of Taihu Lake in spring and autumn are firstly used to simulate backscattering coefficient based on optical closure principle and its spectral properties and temporal and spatial variation of backscattering rate of particles are analyzed. The results show that backscattering coefficients of particles all have a strong correlation with the concentration of total suspended matters and inorganic suspended matters, but a relatively weak correlation with the concentration of organic suspended matters. The index which changes with wavelength ranges from 0.66 to 1.84 with the mean value of 1.29±0.25 in Taihu Lake in spring and from 0.67 to 2.40 with the mean value of 1.24±0.34 in autumn. Besides, the average backscattering rate of Taihu Lake in spring is 0.030, larger in autumn with a value of 0.031. In addition, the backscattering rates of particles have weak dependence of wavelength in Taihu Lake both in spring and autumn. According to simulation results, absorption coefficients between measured and simulated have good uniformity in Taihu Lake both in spring and autumn and the average relative errors are all little than 18%.

By using the complex Gaussian function expansion method and the Wigner distribution function (WDF), the propagation formula of the beam matrix in terms of second-order moments of truncated beams through atmospheric turbulence is derived. It is shown that the divergence problem of second-order moments of truncated beams can be avoided when the complex Gaussian function is applied to the WDF in the z=0 plane. The analytical expressions for second-order moments in the z=0 plane can be obtained and the accuracy can be guaranteed. And then, the beam matrix in terms of second-order moments of truncated beams in turbulence can be obtained. The results are general, i.e. the beam matrix in terms of second-order moments of non-truncated beams in turbulence and that of truncated beams in free space can be treated as two special cases of our results.

Two optical turbulence models, based on the Monin-Obukhov similarity theory, are used to estimate turbulence intensity C2n in atmospheric surface layer. The inputs to the models are the difference of temperature, specific humidity and wind speed taken from two heights above ground. Model results are compared with measurement of C2n with micro-thermometer. The difference of temperature ΔT is the most sensitive parameter. It is avoided to use roughness length, soil and sea surface temperature and specific humidity which are not easy to be measured accurately as input parameters. It is possible to estimate optical turbulence using historical data of standard meteorological parameters.

The propagation performance of high energy laser beams in atmosphere is studied by using extended Huygens-Fresnel diffraction integral, and expressions of axis and peak Strehl ratio are proposed. To examine the scope of these expressions, the results of wave-optics code are compared. It is found that the performance of high energy laser beams in atmosphere can be evaluated by using these expressions when the adaptive optics system is opened, but there is much difference between expressions and the results of wave-optics code under the condition of strong thermal blooming when adaptive optics system is closed.

The estimation of the shifts between sub-images obtained in extended scene Shack-Hartmann wavefront sensing (SH-WFS) are the keys for calculating wavefront errors. The estimation can be got by parabolic interpolation algorithm and the accuracy can reach sub-pixel. The estimation can also be acquired by frequency-domain phase-shift algorithm and the accuracy can increase using frequency-domain iterative algorithm. Based on the later algorithm, the theoretical analysis, simulation and experiment are researched. The results show that the parabolic interpolation algorithm and frequency-domain iterative algorithm get close results in low signal-noise-ratio (SNR), but the later one performs better while SNR is higher than 41.

A method of calibrating static aberrations in non-common optical path of adaptive optics (AO) system by using phase diversity (PD) techniques is proposed. PD techniques are used to estimate the distorted wavefront phase and recover the object imaging by exploiting the collection of two or more short-exposure optical images, one of which is formed by focusing and others by defocusing. In order to compensate the non-common path error, PD algorithm is used to detect the static aberrations of the imaging optical path online when the AO system is working in close-loop state. Then the result is transformed to the deformable mirror′s initial surface. Experimental results indicate that the image quality is improved obviously after calibration. The value of full-width at half-maximum within the object is reduced by about 14% and the remainder error of the system is reduced by about 72%. The remainder error detected in the imaging optical path is consistent with that of the AO close-loop path, and the ability of the PD techniques is verified in optical detection. The proposed method does not need to change the AO optical path and can accurately figure out the system static aberrations in high signal-to-noise ratio (SNR) conditions, so it can be used as a good mean to detect optical path error in the large aperture telescope.

The rate of spontaneous emission of strontium intercombination transition between singlet state and triplet state (5s2)1S0-(5s5p)3P1 is less than the rate of electric dipole transition. Compared with the dipole transition, the fluorescent signal of intercombination transition is very weak. A bias detector is reported which is used to detect the fluorescent signal of this intercombination transition. An ultralow input bias current operational amplifier is applied in this detector to pre-amplify the weak signal, which makes the signal have high signal-to-noise ratio (SNR) and high gain. The detector′s bias can be adjusted. Its gain is on the order of 106 V/W and -3 dB bandwidth is about 1 MHz. According to our experiment, the weak sympathetic fluorescent signal of (5s2)1S0-(5s5p)3P1 intercombination transition is detected by the detector. Consequently, we obtain the fluorescent signal with high SNR and zero bias. Also we detect the high-SNR error signal of the fluorescent signal. Besides, saturated fluorescence spectrum and its error signal are also acquired by the detector. These signals can satisfy the requirement of 689 nm laser frequency stabilization and then be used for strontium optical clock.

This paper proposes a fast simulation method for the three-dimensional (3D) contact hole mask in extreme-ultraviolet lithography. Using the mask diffraction simplified model, an analytical expression of the diffraction spectrum of the contact hole is given, and theory analysis of the pattern shift effect is performed. The mask in the model includes two parts, the absorber and the multilayer structure. The absorber transmission is calculated using the modified thin mask model, and the multilayer reflection is approximated as mirror reflection. Taking 16 nm and 22 nm contact holes with a pitch of 44 nm as examples, the critical dimensional errors of the model are below 0.4 nm by comparison with the rigorous simulations, and the computation speed is increased nearly 100 times. Moreover, considering the equivalent location of the multilayer in the model, a formula is derived to calculate the amount of the pattern shift. The calculation results are consistent with those of the rigorous simulations as well.

As one of the important technical specifications of holographic gratings, the diffraction wavefront aberration directly influences the grating resolution, which depends on the light path adjustment. The q-parameters of Gaussian beam are used to describe the propagation and the transformation by the collimating system of the exposal system; the spatial phase of the two Gaussian beams and the mathematical expression of Moiré pattern are given; then the relation between the system adjustment error and the wavefront aberration of the resulting interference image is discussed. The conclusion shows that the relative defocus of the left and the right collimating systems is the most critical parameter in exposal system, which influences the wavefront aberration strongly. The wavefront aberration also increases according to the decreased focal length. The results obtained from the initial set of experiments are in good agreement with th

Compared with widely-used liquid crystal spatial light modulators, digital micromirror devices (DMDs) have advantages in fast switching speed, high precision display, polarization-independent, high diffraction efficiency, and broadband capability. Therefore, we attempt to apply DMDs as wavelength selectors to tunable fiber lasers and analyze the dependence of diffraction properties of the two-dimension DMD grating on the incident angle, pixel spacing, etc. The diffraction orders and intensity distribution of DMDs in 0.7″ and 0.55″ sizes with different pixel spacings are discussed in detail. The theoretical results show that under the experimental constraint condition, a 0.7″ DMD allows four orders interference irradiance maxima. However, the light intensity is relatively weak due to the condition of far away from “blazed” grating. For a 0.55″ DMD, most of the diffracted radiation is concentrated in one order due to the approximate “blazed” condition. So, a 0.55″ DMD grating as a wavelength tuner is a better choice for the stability of laser systems.

The theoretical analysis for the focusing properties of spiral zone plate is presented. Using the diffraction theory, focusing properties of spiral zone plate and the series-form expression for the diffracted field near the hollow focus are calculated. Moreover numerical simulation and theoretical analysis for the imaging are also carried out by a spiral zone plate using our theoretical results. It shows that the spatial resolution of a spiral zone plate is associated with the zone width of its hollow focus. Experimental results indicate our theoretical analyses are consistent with the experimental test, which give out an effective method for the imaging analysis and numerical simulation of spiral zone plate.

A kind of hydrogen sensing technologic solution is proposed based on optical fiber micromachining. The femtosecond laser with 800 nm wavelength is used to fabricate a Mach-Zehnder (M-Z) interference cavity in single-mode optical fiber, and the palladium(Pd) film is deposited in the M-Z interference cavity by magnetron sputtering processing to make novel optical fiber hydrogen gas sensor. The effect of micromachining process on microcavity interference is analyzed. The resolution of the transmission spectrum is improved by choosing the right processing parameters and the follow-up processing of the cavity. The response to hydrogen of M-Z interference sensor is experimentally studied with the cavity length of 40 μm, the thickness of Pd film of 36 nm and 110 nm respectively. The results show that M-Z interference sensor with Pd film is sensive to hydrogen of different concentrations. The transmission spectrum will offset toward the direction of long wavelength along with the increase of hydrogen concentration, and the response to hydrogen of sensor with 110 nm Pd film is more sensitive than 36 nm Pd film.

The active spontaneous emission (ASE) is the important noise source for erbium-doped fiber amplifier (EDFA), affecting fiber laser based on the EDFA seriously. The theory and practice show that the ASE is closely related with pump methods, so the study on the ASE of erbium-doped fiber (EDF) under the condition of the pulse pumping has important scientific significance. What′s more, pulse pumping makes some sense to the mode-locked laser based on EDFA. The effects of pump pulse with different widths and amplitudes on the ASE are investigated by the theoretical and experimental methods. An approximate analytical solution of output ASE noise average is derived when pump signal is small. The results show that the output amplitude of ASE is proportional to the input width of pump pulse when the pump pulse is small. The new phenomena can be used for the all-optical measurement of a pulse width.

The principle of polarization maintaining fiber (PMF) is analyzed and a three-dimensional model is established by utilizing the finite element method (FEM). The stress distribution and normalized birefringence are obtained through this model. Three pure-optical beat-length measuring systems are carried out for contrastive research and the advantages and disadvantages are described. Experimental results are in good agreement with the theoretical results. Then one simple and effective method to test the beat-length of high-birefringence photonic crystal fiber (Hi-Bi PCF) is chosen and the results indicate that its beat-length is about 1.2 mm. This research provides an effective theoretical method for the analysis of PMF and a convenient experimental system for the beat-length testing of complex structure PMF and Hi-Bi PCF.

The nonlinearity of Mach-Zehnder modulator greatly deteriorates the performance of on-board microwave photonics system. A dual-tone modulation model is presented including optical source, Mach-Zehnder modulator and photodiode, and an exact analytical solution is derived with the method of Fourier expansion, Fourier transform and Gegenbauer addition theory. According to the analytical expression, it can precisely predict the nonlinearity characteristics of the on-board microwave photonics system under different modulation and optimize the system performance. Analytical results indicate that the third-order inter-modulation distortion ratio and the third-order inter-modulation intercept can be approximately calculated with the case when the second-order terms of modulator output signal are included, and the third-order inter-modulation distortion ratio increases and then decreases as the modulation index increases. When the modulation index is less than 1.4674, the third-order inter-modulation distortion ratio of single sideband modulation is at least 6 dB less than that of double sideband modulation and it is suitable for the application of on-board microwave photonics system.

In order to achieve nondestructive testing and imaging of phase objects, and overcome the problems existing in eliminating the interference of zero-order diffraction and conjugate image in phase objects imaging technology by in-line digital holography, a new digital holography method with polarization detection is proposed. Two beams, a reference wave with a horizontal polarization state and an object wave with a vertical polarization state, are synthesized. Using polarization detection method to measure the Stokes parameters of synthesized beam, amplitude and phase difference information of these two beams is obtained. Then a virtual image which contains the information of object beam is constructed. The amplitude and phase information of the object is obtained without removing the zero-order and conjugate image components. In the experiments, a phase object with weak absorption is measured and clean reconstructed images are achieved, including the distributions of amplitude and phase. It is shown that the serious interference of the noise in conventional hologram, the zero-order diffraction and conjugate image can be overcome by applying this algorithm, and it is feasible and effective to extract amplitude and phase information of phase objects.

Fourier transform infrared spectroscopy (FTIR) microscopic imaging technology combines infrared ray spectroscopy with microscopy, so that not only spectral information but also space distribution of sample can be provided. However, because severe peak overlapping exists in the FTIR microscopic image of complex samples, distribution information of the target chemical compound cannot be displayed directly. To overcome the drawbacks, a method of principal component analysis-2nd derivative spectral imaging, combining factor analysis and the spectral unmixing technology is developed. Image analysis of distribution of cholesterol in rabbit arteries with FTIR microscopic imaging technology verifies the feasibility and effectiveness of the proposed method. The experimental results show that the proposed method is an effective method to improve the spectral resolution and find the useful information hidden in overlapping spectral peak.

The applicability of the simplified Gaussian gray diffusion model needs to be further verified theoretically, whose error analysis method relies on the analytical comparison with the typical traditional one. The two models are normalized respectively, a test pixel is chosen, and the evaluating criterion for the simplified model is established by analyzing the relative error of the normalized gray value regarding the test pixel. Star image simulation is conducted, and four relative error curves to the mapping position deviation from the pixel central coordinate are plotted, each of which represents a different case of Gaussian radius σ, manifesting that error decreases as σ increases as a whole. Gray-weighted centroiding method is carried out to the two series of simulated star images generated respectively by the two models. Centroiding absolute error decreases as σ increases, absolute error resulted from simplified model is about 2 orders of magnitude higher than that of the traditional one. Under the conditions of no noise and σ＝0.671, the maximum absolute error from the simplified model is only 0.033 pixel. Simulated results show that the simplified model is no longer applicable when Gaussian radius σ is rather small in terms of shape simulation of image point. Considering that latter algorithms of a star sensor, such as star matching and attitude determination, whose focus is just centroid, the simplified model still possesses applicability due to its advantage of small calculating amount, also because its error magnitude is small enough to be neglected anyway.

Active pixel sensor (APS) complementary metal-oxide-semiconductor (CMOS) sensors have performances competitive with charge coupled device (CCD). A number of potential advantages bring it a good prospect of application hyper-spectral imagery area. Several issues about applications of CMOS sensor for imaging spectrometers are discussed. Noise model is built and sensitivity performance of hyper-spectral imagers using CMOS sensors is analyzed. Spectral image calibration method is proposed based on the structure and features of CMOS detectors. Spectral imaging system including electronics and optics is formed, and analyses are proved by imaging experiment. Results show that CMOS sensors can meet the sensitivity requirement of hyper-spectral imagers and are available for hyper-spectral applications.

The methods which only need one modulated pattern for fringe projection measurement mainly have Fourier transform profilometry, wavelet transform profilometry, and so on. The continuous complex Morlet wavelet based on exponent scale interval and reconstruction is used to retrieve the instantaneous phase of fringe pattern. For the continuous wavelet transform, the great enough noise can change the position of wavelet transform ridge, the probability that the ridge moves up with the influence of noise is greatest. So, the wavelet coefficients corresponding to the ridge and the closest larger scale are chosen, and the maximum between-class variance methord (OTSU) is used to prevent the interference caused by low frequency components; in order to overcome the speckle noise, the result of OTSU is modified and at last, the modified result is used to reconstruct the analytic carrier-frequency signal, and compute the intantaneous phase of the signal. The theoretical analysis and experimental results illustrate that the method is valid and robust.

A method combining the triangulation measurement with multi-frequency grating is proposed. By fully using the three RGB channels of digital projector, the multi-frequency grating and dot array are projected on the surface of the object simultaneously. The extraction of the phase information modulated by height information is controlled comprehensively, and the 3D shape is obtained. In the simulation, when the high-frequency grating′s period shift caused by the step surface is up to 102 orders of magnitudes, the shape can be recovered. Experiments show that a 169 mm sharp height jump and 3 mm tiny details are recovered at the same time by using the method. The method improves the performance of traditional dual-frequency grating, and has the ability to handle larger step surface and maintain the high resolution, which greatly improves the Fourier transform profilometry (FTP) application performance.

Powerful lasers are used to drive plasmas in next-generation particle accelerators and X-ray beams. One shortcoming of these beams is that they typically have a range of energy, caused by the gradual rise of laser power from zero to its maximum level. Using plasma foil as an optical switch, this rising time can be reduced effectively, delivering peak laser power to the plasma on a faster time scale. The method of laser-pulse shaping in the interaction of ultra-intense laser pulses with ultra-thin foils is studied by one-dimensional analytical theory and particle-in-cell simulation. Research results indicate that the pulse can be steepened and its width can be shortened effectively due to the self-consistent nonlinear modulation. In comparison to a single foil, a suitable double-foil scheme could optimize the shaping effect, and a transmitted pulse with both shorter duration and larger amplitude is obtained. When the peak amplitude of the incident pulse is higher than the smash threshold of the foil, the rising time of the shaped pulse could be shortened a lot, and the smash of the foil is the direct reason for this shaping effect.

Surface plasmon polaritions microcavities have attracted considerable attention due to their high quality factor, ultra-small mode volume and wide applications in optoelectronic devices. A kind of surface plasmon polaritions metal-coated microdisk resonator is theoretically simulated and optimized by using finite element method. The quality factor and mode volume of the plasmonic mode of the microdisk are theoretically investigated by considering different parameters of the microdisk such as the bottom radius, the thickness of dielectric, and the thickness of metal coating. High quality factor (>1000), ultra-small mode volume surface plasmon polaritions microcavities are achieved for the optical telecommunication wavelength around 1550 nm. Finally, a refractive index sensing application of the optimized microdisk is also investigated, which achieves a high sentivity of 300 nm/RIU.

The subject in the study of the characteristic and interaction about the bubble occuring near a free liquid surface of water is carried out by the method of laser-generated cavitation bubble and high speed camera system. The experimental results indicate that the dimensionless distance between the bubble and free surface affects the bubble motion and plume of water. The summary of the relation between the dimensionless distance and the maximum radius, period of motion, the height of water column and the time of the plume of water are provided. There are five different plumes for different dimensionless distances. It provides an experimental reference to the research on the interaction of the bubble and free liquid surface.

To match point-sets reliably, an algorithm for point pattern matching based on spectral graph theory and the analysis of geometric consistency is presented. The cost of spectral correspondences between the matched point-sets is obtained by means of eigenvectors of Laplacian matrix. An object function with hybrid form is defined by incorporating geometric consistency represented by neighborhood relationship. The given object function is solved by utilizing iterative relaxation method. Comparative experiments applied to synthetic data and real-world images demonstrate the proposed method possesses better precision and time performance.

During the calibration for a large field of view camera, it usually appears such a situation that the scene is too simplex to satisfy the condition of scene and motion constraints for self-calibration method, the strong three-dimensional condition for three-dimensional calibration and the condition of absolute coplane for flat target plate calibration. It is difficult to fulfill the mentioned conditions while calibrating a camera pointing to the upper-air area. So it calls for a more flexible algorithm when a large field of view camera is calibrated. A calibration method for large field of view camera based on infinite homography is pointed out which just needs approximate position of the camera and at least four noncollinear control points to solve the infinite homography. A coordinate transformation method is also proposed to ensure the stability during the linear solution and optimization process of the infinite homography. The initial camera parameters for Levenberg-Marquardt (LM) optimization algorithm are obtained by decomposing the infinite homography. During the optimization process, the hypothesis that image center is the principal point and the adoption of the first-order radial distortion model will lead to the augment of the redundant freedom, so that the parameters optimization can be realized by using just four image points. The condition needed by the proposed method is facile to satisfy compared with strong three-dimension or absolute coplane. The simulation and actual experiments not only prove the correctness and high precision of this method, but also testify that repeated measurement experiments can be easily and flexibly implemented by this method.

There is a contradiction between field of view and spatial resolution in still-camera-based measurement when the motion range of object is large, and the corresponding calibration procedure is difficult when the object is in the sky or sea. Measuring equipment like photoelectric theodolite can resolve this problem, but its volume is big, it costs very much, and the operation is relatively complicated. To combine the advantages of still camera and photoelectric theodolite, CCD camera is fixed to the two-dimensional (2D) rotation platform as concentrically as possible, constructing a quasi-concentric general theodolite-camera, to conduct high-accuracy measurement. The 2D rotation platform can rotate horizontally and vertically to track object in real time, and provide camera with rotation angle information to update its extrinsic parameters in real time. Photoelectric theodolite requires its optical center and optical axis to coincide with its rotation center and rotation axis respectively. However, no such assembling requirement is imposed on the general theodolite-camera. Theodolite-camera imaging model is constructed based on reasonable hypotheses, and linear solution and adjustment strategy for camera parameters are proposed. The correctness and high accuracy of the proposed imaging model and calibration strategy have been proved by both simulation data and experimental data. Measurement system based on general theodolite-camera possesses many advantages, for example simple structure and assembly, relatively small volume, low costs, panoramic measurement capability and high measuring accuracy. It has a wide and important application prospect.

By using the transfer-matrix method, the multilayer films of photonic crystal composed of SiO2 and TiO2 with high-transmissivity are designed. The characteristics of transmission spectra of the multilayer films are studied. Based on the theory of equivalent layer, the structure of photonic crystal is modified to improve the transmittance in the pass band around specific wavelength, and the optimal parameter is obtained. The results indicate that the minimum transmittance of the optimal structure with lattice paramenter of 150 nm, filling ratio of 0.346 and periodicity of 6, is also up to 96.5% at 400 nm. No matter the incident wave is TM model or TE model, the transmittance do not change significantly, when the incident angles changes from 0° to 45°. The structure can be used for air purification device to improve the photocatalytic efficiency of SiO2 and TiO2 films.

The effect of refractive index on extraordinary transmission properties for metal-dielectric-metal photonic crystal (M-D-MPhC) by changing a thin dielectric layer is studied. Three M-D-MPhC structures combined with square lattice round holes array with different refractive indexes [nd（SU-8）=1.6, nd（SiO2.1N0.3）=1.6 and nd（SiO0.6N1)=1.8] are fabricated using compatible technology with CMOS process, and their transmission spectra are measured using Fourier transform infrared spectrometer. It is found that Au-SiO2.1N0.3-Au structure can obtain better effect of light transmission enhancement and narrower transmission peak in experimental results. It is demonstrated that extraordinary transmission properties for M-D-MPhC depend strongly on both the size of refractive index of middle dielectric and its material fabrication process difference. The finite-difference time-domain (FDTD) method is used to simulate transmission spectra and electric field intensity density distribution of M-D-MPhC with refractive index of 1.6 and 1.8 respectively under the same conditions. Simulation results agree well with the experimental findings.

The output characteristics on a GaAs solar cell and the components which are composed of six pieces of GaAs solar cells in concentration ratio 676 based on Fresnel concentrating system is analyzed. Single-index model of GaAs solar cell is established and compared with experiments. There is a good agreement of theory and experiments with the error less than 7.6%. The experimental results indicate that, with the same concentration ratio, a GaAs solar cell is in concentration ratio 390, and the six pieces of GaAs solar cells is in concentration ratio 281. The short-circuit current of the monolithic cell is enlarged 322 times, and the max electric power is enlarged 316 times in concentration which of the six pieces of GaAs solar cells system is enlarged 275 times and 272 times. The maximum power output of the solar cell is achieved when the energy-flux density is 0.321 MW/m2. The GaAs solar cell works well with a temperature lower than 323 K. The efficiency of the system increases 0.227% as the transmittance of the system improve 0.01. The monolithic GaAs solar cell can generate electric energy 0.015 kW·h and the the cell set of six pieces can generate electric energy 0.076 kW·h for a clear day with daily direct irradiation of 17.212 MJ/m2.

Diffuse reflectance spectroscopy is widely applied in non-invasive detection of human tissue. Depth and transmission path of detecting photons may influence the sensitivity and accuracy of spectral detection. The conventional fiber-optic probes with parallel illumination-collection fibers vertical to skin tissue cannot selectively collect scattered photons from specific penetration depth. For the purpose of human components sensing, the present work designs the specific fiber probes configuration with certain illumination-collection angle or half-ball lens coupled to improve the detection efficiency of dermis. Based on three layers tissue model, Monte Carlo simulation is modified and applied to evaluate the penetration depth of detected photons, percentage of effective photons, effective information loading and detection sensitivity of dermis with each fiber probes. The results indicate that probes proposed in this paper improve the detection efficiency and sensitivity of dermis and the effect of the changes of tissue structure of non-target layer and optical parameters on it is small.

In the technique of ion beam figuring, it often needs to extend the original surface error data to improve the dwell time solving precision on the edge. The virtual extended surface should be smoothly stitched with the original surface error data and should have controllable uncertain ability. Non-uniform rational B-spline (NURBS) surface is usually used in the mechanism fabrication field to model three-dimensional (3D) objects. Using the non-uniform rational B-spline surface and combining with the Zernike polynomial fitting method, a typical tested original free-form surface error data set is extended. The power spectral density curves of typical original surface error and the extended surface error show that the surface error is improved by more than 70% when the error spatial frequency is greater than 0.05 mm-1. This extended surface is also used in the dwell time algorithm, and the forecasted machining precision is improved from 1.18 nm to 0.19 nm in root mean square (RMS) value. The results show that smooth virtual extended surface can be got and the computing precision of the dwell time algorithm can be improved by using non-uniform rational B-spline surface to extend the surface error of the optical components.

With the advantage of its simple structure and good image quality, the pan-Cassegrain is widely used in the field of space optics. Based on the modulation transfer function (MTF) measurement results of the pan-Cassegrain optical lens with the spectrum band of 500~800 nm, and combined with the characteristics of pan-Cassegrain optical system, the cause of chromatic aberration is analyzed, resulting from its high-order aspheric, and a new method to improve the perfermance the optical system is proposed correspondingly based on the minimal chromatic aberration of aspheric. According to the third class optical aberration theory, the surface equation of Schmidt aspheric is analyzed and the minimal chromatic aberration and its zone-aperture height are figured out. Improvement of optical system is achieved correspondingly and the results show that the full-aperture spherochromatic aberration of improved optical system is reduced from 31.4 μm to 4.25 μm, and its MTF values are more than 0.6. The results provide a good guiding to the design of other similarity optical systems.

A U-shaped waveguide-coupled single micro-ring resonator filter structure is proposed based on two-point coupling and optical interferences controlling phase shift. The mathematical model of this structure is inferred by using the transfer matrix method, and the simulation of the spectral line shape of the output port can be obtained by Matlab. By adjusting the distance of two coupling points between U-shaped waveguide and micro-ring, in contrast to traditional two-straight waveguide-coupled single micro-ring filter, the free spectral range (FSR) of the new structure can be doubled when the distance is integer multiples of the circumference of micro-ring. Aimed at the parameters of this structure, the influence of coupling coefficient on the output line is discussed as well, and the perfect extinction ratio of the output spectrum is gained while a narrow bandwidth and a high quality factor are maintained, as the coupling coefficient is 0.018.

A free-space 2×4 90° optical hybrid with electro-optic modulation is designed and fabricated based on the birefringence effect and electro-optic effect of LiNbO3 crystal. It splits and recombines a signal beam and a local oscillator beam by birefringence effect, and the desired phase shift is introduced by electro-optic effect. It realizes the appropriate function of a 2×4 90° optical hybrid under given electric-field conditions. The performance of 2×4 90° optical hybrid is measured experimentally and analyzed. Experimental results show that the optical hybrid has good performance of phase modulation and the proposed 90°optical hybrid. Its phase shift output is tuned electrooptically and phase errors can be compensated by adjusting the applied electric field. It has potential applications in coherent receivers.

A tunable polymer waveguide coupler based on Mach-Zehnder interferometer (MZI) with thermal isolation trenches (TITs) is proposed and analyzed. The temperature distribution in the cross section of polymer waveguides with and without TITs is simulated, which illustrates that the TITs can reduce the power consumption efficiently. The proper thickness of up-cladding waveguide is chosen through investigating the propagation loss of guided modes under aluminium electrode. According to the power consumption influenced by the distance between the TIT and the metal electrode, the optical loss induced by the mode mismatch of the waveguides with and without TITs, and precision of the fabrication craft, the position of TITs is determined. To realize the splitting ratio from 1 to 0, the power of the designed tunable polymer waveguide coupler with TITs is 2.20 mW, which is only 47.4% of the coupler′s power without TITs.

A new flip-chip AlGaInP LED with current-guiding structure is designed. Experimental results show that the output optical power increases by 17.33% than that of the ordinary flip-chip AlGaInP LED with a voltage of 2.19 V at the injection current of 20 mA. Through the current-guiding structure, the injection current of device is actively guided outside of the electrodes, effectively increasing the effective carrier number for luminescence in the active area outside the electrode, while reducing the current crowding phenomenon. This greatly improves the optical efficiency of the device.

A plasmonic dual-band absorber based on a three-layer metal-dielectric-metal structure with an gold elliptical nanodisk array arranged on the top layer is designed and fabricated. Nearly 100% absorption is achieved at dual frequencies in near infrared range due to the plasmonic resonances of incident light and gold elliptical nanodisks along major and minor axes. The designed structure is fabricated by electron beam lithography and the measured reflection spectra match well with simulations. Moreover, it shows that the two absorption peaks can be effectively tuned by coating a temperature-controlled nematic liquid crystal layer on top of the device. The tuning process is simple and repeatable with a maximal tuning range of 22 nm. Owing to its high absorption efficiency and tunable property, this plasmonic absorber must have a great potential in the research field such as solar cells and future photonic circuits.

Bessel-like beam is generated by using thermal light source. The incident condition for the light waves with multi-wavelength passing through axicon simultaneously is analyzed and simulated. The results show that Bessel beam can be generated behind the axicon, but the contrast of the cross section light intensity drops because of the incoherent superposition of the multi-wavelength light waves. In our experiment, halogen light cup is used as thermal light source for generating Bessel beam. A set of optical system is designed to improve the spatial coherence of the light waves, and the Bessel-like beam is generated after the light waves passing the axicon. Comparing the experimental result with the numerical simulation, it is found that Bessel beam obtained from experiment is basically in accord with the numerical calculation. Besides the maximum diffraction-free distance is shorter in the experiment, which is analyzed at the end of the paper.

By using the plane-wave expansion method, the effect of point group symmetry on irreducible Brillouin zone in two-dimensional photonic crystals is studied. Additional cylinder in unit cell of single-cylinder two-dimensiional photonic crystal is designed as symmetrical structures with different operation numbers of symmetry, eigen-frequencies of the five lowest energy bands in the Brillouin zone are calculated. The results show that in the calculation of two-dimensional photonic crystal band structure, if the photonic crystal point group symmetry operation number is n, the irreducible Brillouin zone should be 1/n of the whole first Brillouin zone.

The method on switching the direction of spin accumulation of spin Hall effect of light in reflection is studied theoretically and experimentally. A model describing spin accumulation of reflected light at the interface between air and prism is established. And the qualitative relation between traverse shift and the polarization angle of incident beam is revealed. The direction of spin accumulation will reverse with the increase of the polarization angle of incident light on condition that the incident angle is fixed and less than Brewster angle. But the direction of spin accumulation won′t flip with polarization angle if the incident angle is bigger than Brewster angle. The results show that the direction of spin accumulation can be switched by adjusting the polarization angle of incident light while the incident angle is fixed and less than Brewster angle. The study about the direction of spin accumulation provides a new pathway for modulating the spin Hall effect of light.

We investigate an effective scalable grooved two-dimensional (2D) ion chip design. Grooves are cut between each two parallel radio frequency (RF) electrodes to decrease the laser scattering from ion chip surface, to easily open laser paths to control and to observe the strings of trapped ions. The control of ions has been improved by seperating direct current (DC) electrodes and RF electrodes. The potential distributions are calculated by using the finite element analysis method in order to verify the feasibility of our design. The results show that a scalable ion trap array still can be generated. Thus, this architecture provides a novel grooved 2D planar ion chip design and the arrays of trapped ions can be used in large-scale quantum information processing.

The iridescence and microstructure of nacre in Perna viridis are investigated by fiber spectrometer, scanning electron microscope (SEM) and theoretical simulated software. The following results are obtained: nacre has a typical one-dimensional photonic crystal structure that consists of aragonite sheet and organic matrix; thickness of aragonite sheets gradually increases from 392 nm in growing region to 537 nm in mature region of nacre, which leads to an obvious red shift of photonic band gaps with the same order; dominant wavelength of different regions of nacre increases from 480 nm (blue) to 527 nm (green). The results of measured reflection spectra and theoretical simulation indicate that the 2~4 order photonic band gaps of nacre are in ultraviolet, blue and red band, which cause the complicated iridescence of nacre.

Based on stability and angle precision control of the X-ray diffractometer, the calibration technique of integral diffraction efficiency of the flat crystal is introduced by taking the flat PET crystal as sample. X-ray source is Cu X-ray tube and it is monochromatic at Cu-Kα lines by choosing appropriate high voltage and nickel foils to attenuate bremsstrahlung and Cu-Kβ lines. The slit width in front of proportional counter is 0.05 mm. The source and diffractive curve are scanned in steps of 0.001°. The data show that the integral diffraction efficiency is (1.759±0.002)×10-4 rad at Cu-Kα (8047.823 eV). The results show that this calibration technique is efficient and it can be completed conveniently in common laboratory.

Transmittance spectrum distribution of submicron aluminum-doped zinc oxide (AZO) is discussed. A layer of positive photoresist (PR) is spin coated on AZO thin film and PR mask pattern is acquired with two-beam holographic interference exposure of 325 nm laser. Then it is immersed into 0.5% HCl (mass fraction) water solution to form one-dimensional AZO gratings. The periods and heights of the gratings are adjusted independently from each other and vary between 780~1280 nm and 60~300 nm, respectively. Results show that specular transmittance of 400~900 nm decreases rapidly with grating periods increasing. Bidirectional transmittance distribution functions (BTDF) with normal incidence not only verify this result, but also confirm that diffuse transmittance in the angular range of 30°~80° increases accordingly. The larger the period is, the higher the peak of diffuse transmittance is, and the peak position angle decreases slightly, which is consistent with the law of diffraction angular change with periods obtained by grating equation.

Two kinds of alkyl substitution quinacridone derivative C6DHQA and C16DMQA X-type Langmuir-Blodgett (LB) films are prepared. The optical characteristics are studied by UV-visual spectrum, steady state and time resolved fluorescence. The experimental results show that the absorption spectrum of the C16DMQA has a whole red shift compared with C6DHQA′s. It shows that the energy level is lower with the added alkyl chain. The absorption spectrum of their LB films has a whole red shift compared with their solution. It shows that the two kinds molecule formed J-aggregation in LB films. The two kinds of material in chloroform solution and LB films both have strong flourescence emission. The absorption spectrum and the flourescence spetrum of the two kinds of material solution have mirror symmetry. But their LB films′s are asymmetrical. The third peak relative intensity of C6DHQA and C16DMQA LB films has a larger difference. The fluorescence lifetime at three fluorescenct emission peaks of C6DHQA solution is about 21 ns and C16DMQA′s is about 22 ns. It is obviously reduced as in LB films. And it is obviously diffrerent at the third peaks of C6DHQA compared with C16DMQA. All these differences are due to closer-arrangement of C16DMQA molecule on the substrate, the intermolecular interactions stronger and has a bigger influence on its energy level structure than C6DHQA molecule.

Amorphous silicon oxide (a-SiOx) films are prepared using plasma enhanced chemical vapor deposition technique. The microstructural and optical characteristics of a-SiOx films are investigated by Fourier transformed infrared spectra, optical absorption spectra, and steady/time-resolved photoluminescence (PL) spectra. With the CO2 flow rate increasing, the band gap and PL intensity of the films increase, the PL peak moves toward high energies, and the full width at half maximum of the PL are widened. In addition, the decay time at PL peaks increases from 6.2 ns to 21 ns with oxygen content enhancing. However, linearly decreased decay time with energy increasing is found for one sample. Optical transitions among band tail states of amorphous materials are considered as the main light emission mechanism based on the analysis of optical absorption, emission and decay characteristics.

In order to investigate cross-media color reproduction performances on three surround parameters (dark, dim, average) of CIECAM02 color appearance model, color reproduction experiments under the three corresponding ambient lighting conditions are implemented between print samples viewed in a cabinet and reproduced samples presented on a self-luminous display. Memory matching and pair comparison methods are employed in psychophysical experiments. Detailed analysis and comparison of the experimental data indicate that the color samples reproduced by parameter “dim” performed well in all three conditions, while the performance of parameters “dark” and “average” are dependent, in some extent, on the lightness and chroma of color. The color samples with lower lightness work well when they are reproduced by parameter “dark” and viewed in Dark condition, but they perform poor when being viewed in Average condition and reproduced using parameter “average”. As for the relatively lighter color samples the reproduction performances are not statistically different between the cases of parameters “dark” and “average” when they are viewed in the corresponding Dark and Average lighting conditions.

A series of experiments are conducted using printing samples to investigate the effects of different gloss and different color-difference magnitudes. The results are used to reveal these effects. In addition, seven different color spaces basded on CIELAB DIN99, OSA and CIECAM02 are tested using these data. It is found that comparing the performance of local uniformity and global uniformity, OSA-Gp-Eu and DIN99d always perform the best, and all spaces outperform CIELAB and OSA.