Two schemes of frequency selectivity utilized birefringent filter are analyzed theoretically,and the appropriate structure of frequency selectivity was chosen. In experiment, by using the stationary wave cavity and the structure of double KTP/single BP, 1.12 W single-frequency green steady output was obtained with 8 W pump power, moreover, the relation of stability of single-frequency laser and outside disturb was discussed simply.

Two kinds of Q-switched rate equation including and non-including lower level relaxation are analyzed. As an example, diode side-pumped Q-switched Nd∶YAG laser is studied using the two kinds of rate equation. The variations of upper and lower level population are given. Q-switched pulse waveform, peak power and pulse energy are calculated. In addition, sub-pulse and tail phenomena are also explained.

In this paper the qulse pumped Yb-doped double-clad fiber laser is studied experimentally. Pumped by 100 μs long pulses, which repetition rate ranged from 2 kHz to 8 kHz, the fiber laser outputs shorter than 10ns stable pulses. Further the dynamics of the output character of the fiber laser is analyzed. For the first time, the authors provide that the theory of the co-operation of Rayleigh scattering (RS) and stimulated Brillouin scattering (SBS), which results in ns pulses output from the pulse pumped fiber laser.

It is reported the experimental study of ultrashort pulse Yb~3+ -doped fiber ring laser. The Yb~3+ -doped fiber is pumped using a 976 nm semiconductor laser. Using the additive pulse mode-locking based on nonlinear polarization evolution, the Yb~3+ -doped fiber laser achieves stable mode-locking by adjusting the orientation of PC. The maximum output power of the laser is 7.02 mW, at the repetition rate of 13.7 MHz corresponding to ~6nm spectrum width.

A design of LD-pumped Nd∶YVO_4/LBO blue laser at 457 nm is presented in the paper.An optimized-designedCW914nmlaseratroomtemperatureisobtained.Usingtype-Icriticialphase-matchingLBOcrystal,457nm blue laser is obtained by 914 nm intracavity frequency doubling. The maximum laser output power of 20 mW is obtained when a incident pump laser of 1.7 W is used. The optical-to-optical conversion is up to 1.2%, the power instability in 24 h is better than ±3%.

It is reported that the slot of microcutting Si wafer by second and third harmonic output of YAG laser is narrower in water bath than in air environment. The surface morphology and etching rate for water bath and air environment are compared in detail. The cutting gap as small as 10 μm with edge fluctuation less than 5 μm is obtained in water bath by 355 nm laser. This technology may be helpful for industrial applications.

The structure of Vertical-Cavity Surface-Emitting Lasers (VCSEL) has been grown on (100)2° off toward A n-GaAs(Si) substrate by MBE. The numbers of reflectors in top and bottom Distributed Bragg Reflector (DBR) structures are 24.5 pairs and 34.5 pairs, respectively. The high quality VCSEL structure is characterized by PL, SEM and X-ray double crystal diffraction (XRD). The peak wavelength of PL spectrum is 837.0 nm and the FWHM is 28.9 nm at room temperature. The structure parameters of VCSEL are obtained from the rocking curve. The first and second satellite peaks around the main (“0” level) reflection peak appear in the rocking curve. The FWHM of diffraction peaks of “0” level and GaAs substrate are 12.56″ and 11.79″, respectively, which are quite close, showing much higher integrity of the crystal lattice. The experimental results show that the resonant wavelength of cavity modes (837.2 nm) and the peak wavelength of PL spectrum are well matched.

In order to realize the fabrication of binary beam shaping element with complex phase structures, a new method of making the relief phase structures under the dot-by-dot exposure mode is presented by using laser direct writing (LDW) system with the square-spot. The size of the square spot obtained with the projection optical configuration is set to match with the minimum phase unit which lead to exposure mode can be easily controlled. The diffraction properties of the phase unit structures etched with single Gaussian spot and square spot are discussed. The binary beam-shaping elements with two-steps by square-spot exposure have been achieved to 31% +1 order diffraction efficiency. The experimental results are given.

A broadband polarization switch consisting of an active twisted nematic liquid crystal cell and two passive uniaxial compensation films is proposed. The conjugate gradient method was used for optimizing the device parameters. Simulation results indicate that the polarization switch exhibits a broad bandwidth with 400~700 nm, high contrast ratio and fast response time with 20~30 ms.

A design of directional coupler based polymeric electro-optical switch is presented, focusing on the reduction of both wavelength dependence and the sensitivity of optical characteristics to coupling length. A optimized configuration of the switch was found with a <0.3 dB insertion loss variation for the coupling length to change from 3800 to 4300 μm, making it feasible to form the polymer structure on silicon substrate by rubber molding process or other rapid printing techniques. The characteristics of the optical switch were analyzed by BPM simulations and an insertion loss as low as 0.4~0.6 dB was obtained, along with a crosstalk of-32 dB and a PDL of 0.08 dB. The driving voltage was found to be 42 V when r_~33 =14 pm/V.

A new structure with both ridge waveguide and T-type electrode is given to enhance the bandwidth of electro-optic modulator.After calculating and optimizing by the finite-element method,as an example,an excellent modulator,whose bandwidth is 153 GHz,half wave voltage is 8.55 V,characteristic impedance is 44 Ω and driving power is 0.833 W is designed.

Using Planck′s formula, accurate formula of specific detectivity is got for ideal photon detector limited to background noise. Contrasting accurate formula with traditional approximate formula, the error analysis has been done. The results show that the error of approximate formula is quite small and it can be used generally.

A new type of high power white LEDs (HPW-LEDs) based on metal core printed circuit board (MCPCB) and chip on board (COB) technique is designed and demonstrated, its opto-electrical characteristics are measured. The saturated characteristics of luminous flux is obvious at the forward current 800 mA (corresponding the forward power 3.3 mW), and the saturated characteristics of voltage-current is obvious until the forward current added to 800 mA, (corresponding the forward power 3.3 mW). These results show the MCPCB and COB technique could solve the problem of heat transfers very well, so the HPW-LEDs could work at a high level forward power. At the same time, the spectrum, luminous flux, and chromaticity coordinates of HPW-LEDs change with forward current are studied.

Capsule model of gold nanorods is put forward and absorption spectra are calculated using T-matrix method developed by Waterman. Experimental spectra and calculated spectra agree well. The absorption maximum at around 520 nm is corresponding to the transverse surface plasmon resonance (transverse mode), while the absorption maximum at longer wavelength is corresponding to the longitudinal surface plasmon resonance (longitudinal mode). The absorption maximum of longitudinal mode red-shifts significantly with increasing aspect ratio of gold nanorods, while the absorption maximum of transverse mode blue-shifts slightly. Besides, calculations show that the medium dielectric constants decrease nonlinearly with increasing aspect ratio of gold nanorods.

The resonance amplify of Stokes wave of C_6H_6 is reported by using fluorescence enhancement method.With a specified concentration of R6G, the first-and second-order Stokes lines are increased respectively by 3.81and 6.1 times relative to that of pure C_6H_6.The physical mechanism of the resonance enhancement is discussed.

A practicable method for liquid-surface acoustic-wave at the frequencies of a few tens Hertz, based on the combination of optical interference and scanning wave slope, has been developed. Moreover, this technique was used to determine the attenuation coefficient of the surface wave at these frequencies in real time.

A three-wavelength frequency-domain photon migration spectroscopy instrument using in-phase and quadrature (I&Q) demodulation technique in a 140-MHz homodyne system was described here. A calibration procedure was employed to qualify absorption coefficient and reduced scattering coefficient with single source-detector separation. The performance of the frequency-domain NIRS to quantify blood oxygen saturation and the concentration of oxy-and deoxy-hemoglobin is examined with experimental measurements on a yeast-blood model. The results of the forarm arterial occlusion experiment was in good agreement with those measured

Attenuated total reflection (ATR) FTIR spectra of benign and malignant breast tumor tissues from 32 female patients have been determined and investigated. The spectral differences and changes (shape, peak position and relative intensities) have been observed between these two types of samples. In comparison with the benign tumor tissues, the mainly characteristic changes of malignant breast tissues involve: 1) The secondary structure of proteins in malignant tumor tissues is composed mainly of α-helix and random coil, in which α-helix structure is dominant. 2) The absorption band near 1160 cm~-1 due to the C-O(H) stretching modes of serine, threonine, tyrosine groups evidently shifted to a higher wavenumber, suggesting that the intermolecular hydrogen bonds were nearly broken, and the collagen absorption peaks at 1205 cm~-1 , 1278 cm~-1 and 1338 cm~-1 became lower or disappeared, showing its relative contents decreased. 3) The bands from the symmetric and asymmetric stretching modes of the PO-_2 of the phosph

Femtosecond-time-resolved fluorescence spectroscopy technology has been carried out to study the fluorescence spectral properties and energy transfer properties in homotrimer and heterotrimer of the light-harvesting complex Ⅱprepared from Bryopsis corticulans , which is excitated at 495 nm and room temperature . Both homotrimer and heterotrimer have obtained five spectral components by Gauss analysis, and each of which reflects different spectral properties. Furthermore, the fluorescence spectra of the two complexes have been analyzed and compared. In addition, Triexponential time fitting for the fluorescence decay curve of homotrimer yields 3 components lifetimes of 165±8.5 fs, 2.2±0.6 ps and 5.1±0.1 ns, of hetermotrimer receives 3 components lifetimes of 255±6.3 fs, 4±0.8 ps and 3.8±0.1 ns, and all of which have been given ascription. Here, the two shorter time components of homotrimer are faster than those of heterotrimer.Which shows that the protein binding

Spirulina platensis was mutated by He-Ne Laser (wave length 632 nm,power 10 mW),irradiated for some time,some strains which grow faster than others were chosen to measure the content of β-carotene,protein and polysaccharide,then the strains with high production,high content of β-carotene and protein ext were selected.The result shows that,spirulina platensis sp MS-1,MS-2 and MS-3 which were irradiated by He-Ne laser for 15 min and 25 min,compared with original strain IS,its morphologh parameter changed,morphologh parameter shorted,helix tighted and grow speed was increased obviously.The content of β-carotene of MS-1 was increased by 18.1%,the content of protein and polysaccharide of MS-3 were also increased.In addition,the peak value of original strain was changed compared with the mutant strains by the ultraviolet spectrum of chlorophyll and carotenoid.It showed the mutagenesis domino effect of spirulina platensis by He-Ne Laser.

A special kind of sampled fiber Bragg grating (FBG) was proposed and researched: chirped-sinc-sampled FBG. By chirping the sampling period of sinc-sampled FBG with uniform grating period, both the accurate number of reflective wavelength channels and chromatic dispersion slope compensation can be obtained. By chirping the sampling period of sinc-sampled FBG with chirped grating period, the number of wavelength channels we needed and compensate both the dispersion and dispersion slope can be controlled simultaneously. Meanwhile, nearly identical reflectivity in all wavelength channels is also obtained. By utilizing chirped-sinc-sampled FBG, both the dispersion and dispersion slope can be simultaneously compensated for various transmission fibers.

A new two-stage L-band erbium doped fiber amplifier (EDFA) structure with a single fiber grating is introduced to solve the problem of poor power conversion efficiency of a conventional L-band EDFA. A mid-way isolator is used in the structure to improve the noise figure. The fiber grating is used to reflect the wasted C-band backward amplified spontaneous emission (ASE). The influence of the pump power ratio and the Bragg wavelength to the characteristics of this EDFA is studied experimentally. For such an EDFA structure with a pump power of 70 mW, 22.26 dB gain and 4.96 dB noise figure is obtained for a 1570 nm signal with an input power of-30 dBm.

The effects of various factors on the performances of edge routers are analyzed in details. The results show that the delay requirement of different class of services can be satisfied by controlling the relative maximum assembly delay. Large burst size variation may lead to unfair in channel assignment. The more the number of edge routers in the OBS networks is, the higher Burst loss rate is. Low burst loss rate and high efficient can be achieved by increasing the number of output channels while the total capacity is invariable. However, the effect is degraded with the increase of the number of edge routers in the OBS networks.

The propagation of quantum soliton in lossless optical fiber is numerically simulated by the use of the linearization approximation and split step Furior .The evolution of quantum noise of solitons is obtained by solving quantum nonlinear Schrdinger equation .The squeezing ratio is calculated.The results show that squeezing still survives but will reach a limit as the propagation distance increases.

A joint capacity allocation approach is proposed to optimize spare capacity in multi-layer survivable networks. Depending on a full overview of all network layers, the joint capacity allocation approach can realize the maximum sharing of spare capacity among layers. The spare capacity allocation problem in multi-layer survivable networks is formulated through Integer Linear Programming, while for large-scale networks, a genetic algorithm is also proposed for possible optimal solution. Numerical results illustrate that the proposed approach is much more cost-effective. Due to the introduction of coordination among different layers, the proposed approach can also avoid the backhauling problem.

An atmospheric optical communication link is considered,in which the laser source is a narrowband Gaussian Shell beam and the link is working in the weak fluctuation regime.The effects of atmospheric turbulence strength and degree of source spatial coherence on the angle-of-arrival are examined.To accomplish this,we have used the cross-spectral density function of the narrowband fields in place of the mutual coherence function and have used the power spectral density of the refractive-index fluctuations which include the factor of small-and large-scale sizes turbulence eddies.Expressions for the wave structure function and the variance of the angle-of-arrival of Gaussian Schell beam propagation in isotropic and homogeneous atmospheric turbulence are developed.The analysis indicates the turbulence spreading ofthe beam and the degree of source spatial coherence are two main factors which affect the wave structure function and the variance of the angle-of-arrival of the propagating beam.

The operational principle for resonant cavity of fiber optic Farby-Perot is analyzed, in addition to the selection for its operating point. The relationship of optical phase sensitivity of resonant cavity and its fineness was deduced. The theoretical formula and curve are presented. The above system is compared with the interference system of fiber optic Math-Zehnder,the great difference of the two interference system is pointed out as phase sensitivity considered.The unique advantages of fiber optic Fabry-Perot interference system are demonstrated. The transmittance curve of fiber optic Fabry-Perot interference and fiber optic Math-Zehnder interference were calculated and plotted with Mathcad software.The experimental system of fiber optic Fabry-Perot interference as well as the transmittance curve pictures taken in experiment is introduced. A method was given,with which the effective fineness calculation can be achieved. The experimental pictures was well in accordance with theoretical cures.

Based on the effect of edge-filter, it is for the first time that a novel long-period fiber grating is used as sensor to measure static and dynamic strain. The input signal from a light source of single wavelength is attenuated by the long-period fiber grating, and then received by a photodetector. The loss band of the LPFG will shift in the direction to shorter wavelength when the grating is strained. Due to the effect of edge-filter, the light intensity received by the photodetector will change in response. As a result, the electrical output of the photodetector can be used to reflect the strain forced on the grating. In the static measurement, the result shows that the relation between the electrical output of the sensor and the strain forms a conic. The resolution of this sensing system is better than 10 με, and the error is about ±10 με. This system can response dynamic strain over 5 kHz too. This sensor system is low-cost and fast.

The ELACs of all kinds of components in the FTO (French Test Object) are investigated. And the combined method ( exposure transmission function , peeling onion,and Monte Carlo method ) is used. Many excited results have been worked out. The spectrum is translating and narrowing to the value which is according to the minimal mass attenuation coefficient of the element in the radiography. Because of which, the ELAC decreases while the X-ray goes deeper in the mass. The average efficient linear attenuation coefficient of copper is 0.299(1±3.0%)cm~-1 , while tungsten 0.829(1±2.7%)cm~-1 .With which the high precision density contribution of the components can be got in the reconstruction.

In order to meet the precision of picture nicely in scanning and imaging system ,uniform time sampling technology is discussed in theory.it is discussed that if new sampling technology of uniform angle can be used in the future sensing instrument.Two sampling technologies have been used in an IRFPA instrument successfully,the pictures of scanning system are reported that uniform angle sampling technology can be avoided to make picture distored.

The high repetition rate sweep circuit Streak camera MOS transistor sweep circuit

It is mainly discussed how to use high-speed telecamera system with a fixed directing to accomplish the measurement of vector missing the suppositional target in shooting practice of one certain type of the missile.The demonstration of the feasibility,the research of the procedure and the analysis of the accuracy are presented.

Gamut mapping is the key element to get satisfactory image reproduction. First, a practical method is used to realize the transform from RGB values of CRT monitor to spectral tristimulus values. The printing paper gamut is predicted by Beer′s law. Further, a non-linear compression method is proposed to realize the gamut mapping. At the same time, the virtual gamut is defined and studied. The result indicates that this model has good practicality for the CMS (Color Management System) of digital photofinishing. This method is applied to high-technology industry with satisfying performance.

A new adaptive method of multi-spectral image and panchromatic image is presented. The experiment results show that the new method can not only reach minimized color distortion and maximized spatial detail, but also have adaption in all kinds of images.

In order to enhance the speed of image processing , the optic wavelet transform is applied to design of vision system based on the method of photoelectric hybrid implementation. Using the theory of optical information processing of 4f correlator, a library of wavelet function filters on the spatial light modulator with electro-address is constructed. It is achieved by computer programming in the spatial frequency domain, so the features of object can be extracted and recognized. The research results show the optic wavelet transform based vision system is reasonable and feasible. Optical information based image feature extraction will enhance the speed of vision information processing.

In order to improve recognition effect of joint transform correlator(JTC) , morphological algorithm is introduced to detect image edge in the input plane. Width adjustability of morphological edge detection is put forward to improve JTC recognition effect . Experiment indicates that the modified algorithm makes JTC have enough light intensity and higher discrimination capability.

A method of speckle Correlation measuring is presented. It performs fractional Fourier transform instead of Fourier transform in matched filtering Correlation to obtain better recognition peak. Based on the exponential property of fractional Fourier transform, The shifting problem of fractional domain spectrum from the shift-variant property of fractional Fourier transform is solved by use of phase modulation to the specklegram,. The results of simulation and displacement fields measuring of object stretched indicate that this method is feasible, and Fractional Correlation peaks can be optimized through choosing the transform orders and phase modulation function.

Various resonant modes of single-point defects two-dimensional square dielectric photonic crystals cavity are calculated by using the plane-waves expansion method. The degeneracy of resonant modes is investigated based on the symmetry relation of the cavity modes. The C4v symmetry photonic crystal cavity tends to have either a pair of doubly degenerate modes or non-degenerate modes. Dipoles and hexapoles are doubly degenerate modes, a quadrupole and a monopole are non-degenerate modes, and the 90°rotated state is its orthogonal state for doubly degenerate modes. Thus, we can determine the degeneracy of modes by simply inspecting mode symmetries.

The characteristic curves of effective refractive index of infinite and finite photonic crystal are calculated and analyzed by using the dispersive relation and transmission coefficients respectively. The results show the dispersive curve of one-dimensional photonic crystals have the normal dispersion in the transmitted bands and abnormal dispersion in the band gaps which is similar with that of elastic electronic dipolar. Based upon our calculations, the explanation of some contradictive places or the difference in the relative literatures is given out.

The ion current density (ICD) of End-Hall ion source at different conditions were determined with a Frady cup. The ZrO_2 films were deposited with different Ar+ ICD. The influence of ICD on refractive index, crystal phases, index inhomogeneity of films was studied. The effect of ICD on refractive index was analysed by a momentum transfer model. According to a thermal-spike theory, it is evidenced that the ICD didn′t influence the crystal structure of the films.

Two-photon absorpuion and frequency upconversion properties of CEASP-Ce and CEASPI dye solutions have been measured. The upconversion fluorescence was measured to be around 610 nm when the two dyes were pumped with 930 nm laser. A good directional, high efficiency, narrow spectral width amplified spontaneous emission(ASE)could been observed when the concentration of the dyes were increased. The output verse input efficiency of the two dyes was different, but the overall net upconversion of them pumped by 975 nm laser reached about 20%. A comparison was made between the two samples though their different parameters, a result can be concluded from the structure of two samples that Ce~3+ affects the process of ASE by enhancing the absorption cross section.

The temporal and photo-statistic characteristics of silicon APD photon emission were got experimentally by measuring its photon statistics under breakdown condition. Compared with corresponding Poisson distribution and thermal field photon statistic distribution, the photo-statistic distribution of APD photon emission with 10 ms bin time was found to be Super-Poisson distribution. The fluorescence spectrum of the APD photon emission was also achieved in experiment.