Based on cross correlation coefficient and absolute difference algorithms and the principle of Hartmann Shack wavefront sensor, the feasibility of correlating Hartmann Shack wavefront sensor used for low contrast and extended object is studied according to the indoors solar granulation simulator. The results show that correlating Hartmann Shack wavefront sensor can be efficiently used to detect wavefront aberration for low contrast and extended object.

In astronomical speckle imaging technique, the method of iterative least square (building block) proposed by Hofmann et al. can avoid the complex phase retrieving process when phase spectrum was recovered from the bispctrum of an observated object image, and so the phase error transmission and accumlation were removed too. But this method needs a great quantity of iterative steps of putting blocks and a long term processing. For to raise the efficiency of the method, the means of “iterative shift and add” was used for pretreating the speckle images of the object. After a few steps of shift and adding, the basic structure and distribution of the object image were provided quickly and the position of points putting blocks was got, and so blind putting was avoided, thus the iterative steps were reduced greatly and the efficiency of the method can be increased obviously.

The collinear multiple wavelength and multiple storage are demonstrated by using DFWM setup with Ar + collinear output laser. The employed sample is a new synthesis organic conductive material. The multiple wavelength collinear real time readout and permanent storage are performed. The excellent storage photograph are obtained.

A new self mixing interference structure including the pre feedback is proposed and its model is established. It is confirmed by computer simulating and experiment that the pre feedback one can extend the measuring range and increase the signal to noise ratio and obtain the sawtooth interference signal from a rough surface.

The modulation transfer function (MTF) is an important parameter indicating the performance of an imaging system. While in the testing of MTF of CCD camera, there is often a difference between test value and actual value of MTF due to the use of a rectangular bar target rather than a sinusoidal bar target. The MTF test result at Nyquist frequency of CCD camera system is theoretically analyzed.

The resolution limitation in conventional interferometric imaging is analyzed. A method based on synthesizing pieces of fringe to improve the resolution is presented, and an experiment is designed to demonstrate the feasibility.

Based on the principle of polarizing modulation, a new method of phase retardation measurement is given. A polarization beam splitter is used instead of polarizer, and a normalized parameter from Jones matrix is introduced to attribute the retardation under test. The measurement deviation obtained is less than 0.8%.

A new half oblate consisted model is built upon the probability distribution concept from the scattering characteristics of the particles. It is suggested that η represents the shape factor, T(η) represents the shape impact factor and P(η) represents the shape probability distribution. The size distribution function P s (a) is substituted by the character distribution function P(a,η). After that, a inversion equation of the function P(η,a) and a method for the measurement are established upon the Mie scattering theory, which is supported by using arbitrary particles such as mineral particles in the experiment, and a good result is obtained.

A double integrating spheres system for measuring the optical properties of tissue was designed. The optical properties have been measured (at 632.8 nm) when human whole blood and albumen were slowly heated in water bath at room temperature (23 ℃) and 37 ℃～80 ℃ for 15 minutes. There were different changes in optical properties when albumen and whole blood underwent denaturation and conformation changes. It was the reason that there were differet components between the two samples. It is demonstrated that physiological characteristic is described by optical properties of tissue. Optical detecting will provide a new method to monitor thermaltherapy.

The angular momentum orientation and alignment in single rotational states of the IR inactive vibrational mode (v″=1) in the electronic ground state of acetylene (X 1∑ + g, v″ 2=1,J″) has been selectively prepared by using circularly and linearly polarized laser stimulated Raman pumping. From the induced electronic transition fluorescence spectra by a circularly and linearly polarized UV laser, A 1* A u(v″=1)←X 1∑ + g (v″ 2=1), the A (1) 0 (orientation) of C 2H 2 (X 1∑ + g, v″ 2=1,J″=4,7,8,9,10,11,12,13) are measured directly in the range between 0.7 and 0.8. The A (2) 0 (alignment) for J″=2,3,4,5,6,7,8,9,11 is -0.7～-0.9. This results show that the spatial population of angular momentum of C 2H 2 molecule before reactions can be controlled by this laser pumping technique.

Second harmonic generation (SHG) is experimentally demonstrated in tunable mini TEA CO 2 laser with home made AgGaSe 2 crystal, which has the dimension 7 mm×8 mm× 12 mm. 12 SH lines generated from CO 2 spectrum region 10.6 μm～9.6 μm were obtained. The maximum SH output was found to be 1.32 mJ [10P(16)]. And, in 10P(18) line, the maximum energy conversion was 4%.

A passively Q switched laser diode end pumped Nd∶YVO 4 laser is demonstrated in which a GaAs film is used as the saturable absorber. The pulse width, pulse energy and pulse repetition rate of different output coupler are measured. At 4 W pumping power, stable laser pulse as short as 30 ns with 8 μJ energy and 60 kHz pulse repetition rate can be generated with this laser. Meanwhile, the Q switching dynamics is theoretically studied based on the rate equations. Some phenomena generated in the laser are analyzed.

The effect of Er doped fiber amplifier (EDFA) saturation on the frequency filtering characteristic of active fiber ring resonator is studied theoretically and experimentally, when a high input power signal is injected and EDFA saturation is induced. The optimization of active fiber ring resonator is discussed considering the effect of EDFA saturation.

The saturable absorber Cr,Ca∶YAG based on the undoped YAG was successfully grown by liquid phase epitaxy. The results from the absorption spectra analysis of the Cr,Ca∶YAG show that the main features in visible and near infrared range are the same as these by the Czochralski. Nevertheless, there is a weak absorption band centered around λ≈750 nm, which is first observed in the YAG lattice field. This weak band is interpreted as the arising from tetrahedrally coordinated Cr 5+ , and proposed to assign to the electric dipole allowed 2B 2( 2E)→ 2B 1( 2T 2) transition.

The nonlinear phase shift and the changes of fundamental wave amplitude caused by Cherenkov cascading second order nonlinearity have been analyzed and optimized, taking into account the propagation loss. According to author′s calculation, the nonlinear phase shift and the change of fundamental power are strongly dependent on two parameters: the thickness of the waveguide and the fundamental light wavelength. The results show that, a very large nonlinear phase shift (>2π) could be attained with a very small depletion of fundamental power even if the reversal period is not introduced into the waveguide by properly choosing the two parameters, which is very attractive to the realization of the all optical switches. Many useful results are obtained which are important to the research and development of all optical switches.

Compression of ultrashort pulses in strongly birefringent optical fibers is studied. When the third order dispersion is considered, one of polarization pulse compression is enhanced and the other polarization pulse compression is suppressed due to the interaction of the third order dispersion and nonlinear effects. Slow soliton is compressed in the fiber with positive third order dispersion, fast soliton is done in the fiber with negative third order dispersion. The large value of third order dispersion parameter, the more evident the compression effect.

The orientational photorefractive effects were observed in nematic liquid crystals deoped with electron donor and acceptor organic molecules. This kind of materials exhibits significantly their enhanced photorefractive performance. Two beam coupling and four wave mixing experiments are performed to characterize the photophysics of these novel materials. Polymer stabilization alters the charge transport and trapping characteristics of LCs, resulting in persistent lived gratings. Furthermore, the net photorefractive gain (Γ) of 441 cm -1 in two beam coupling, and the diffraction efficiency of 58% in four wave mixing were also measured.

Integrated acousto optical tunable filters (AOTF) have potential application in WDM optical networks because of some advanced properties, especially, the unique property of simultaneous multiwavelength filtering. The exact coupling equations with two acoustic waves travelling simultaneously were derived. Based on the coupling equations, some numerical results of conversion characteristics are given and the fluctuation of the main peak, the center wavelength and the FWHM (full width of half maximum) are analyzed with respect to time. The reasons for serious distortion and the higher crosstalk for narrower channel sapcings are discussed. Considering the drawbacks of the collinear integrated acousto optical tunable filter in multiwavelength operation, use of quasi collinear acousto optical mode converter for improving the conversion characteristics of AOTF is proposed.

The relation curves of reaction of acoustic and optical wave under the momentum matching condition are presented. It is found that, in the scope of visible and infrared spectrum range, only when the angle between the incident ray and the crystal optical axis is about 56°, there exists a unique acoustic wave vector, which enables two situations [o (the ordinary ray) in e (the extraordinary ray) out and e in o out] to satisfy the parallel tangent momentum matching condition, and the wavelength of two diffraction rays equals each other. This specific angle is labeled as the equivalent point in theoretical design of acousto optic tunable filter (AOTF). This result has been proved through experiments. Applying equivalent point theory in designing AOTF can improve the signal to noise ratio of spectrum measurement significantly without sacrificing any wavelength resolution.

The rapid turn-on process of nonlinear photoconductive semiconductor switch is always associated with the formation of filamentary current. Some turn on characteristics of nonlinear photoconductive semiconductor switches are analyzed based on the assumption that the mechanism of the turn on in photoconductive semiconductor switches is the streamer discharge. The results, with carrier lifetime, optical absorption length, impact ionization coefficient, initial carrier concentration considered, fit with the experimental results well. This discussion corroborates the assumption and is helpful to the full understanding of the physical processes occurred in nonlinear PCSS. Some methods of improving and controlling the operational characteristics of PCSS are also given.

An all fiber reflected Mach Zehnder interferometric multi wavelength filter was demonstrated and studied in detail. The relationships between the splitting ratio of the couplers, the length difference of the two arms and the intensity transmission were obtained. The conclusions had important value in designing and manufacturing the components with various capabilities. This kind of filter was fabricated with fused biconical taper technics in experiment. The theoretical results were agreement with the experimental ones.

An apodization chirp optical fiber grating (OFG) is fabricated by scanning method. This OFG is 13.5 cm long with 0.447 nm bandwidth and its reflectivity is flatness with ripple coefficient less than 1 dB, while its ripple coefficient of time delay is less than 20 ps. The dispersion of 200 km G.652 optical fiber is compensated by the grating, and more than 98% dispersion is compensated (the original pulse width is 36.78 ps, after compensation the pulse width is 37.23 ps).

The operation principle and construction design of an all fiberoptic accelerometer based on compliant cylinders are described. The accelerometer is fabricated by supporting a seismic mass between two compliant cylinders, which tightly wrapped with single mode optical fiber and acted as two arms of the optical fiber interferometer. The two arms are coated with Al films to enhance the reflectivity. Preliminary test results indicated that the accelerometer has better frequency response well above the resonant frequency, and the output signal is in correspondence with the input.

A new method is proposed to build a micromachined tunable optical filter array on glass base in visible band. The analysis result based on finite element shows that the optical performance is strongly influenced by the curved 3 D surface of the suspended electrostaticly driving layer.

(HgCd)Te detectors have strong Franz Keldysh (F-K) effect and the effective intensity of F-K effect of the (HgCd)Te detector has close relation to bias voltage,. According to this principle, electronic circuit of controlling (HgCd)Te detector′s photon absorption coefficient has been designed and fabricated. Experimental results show that the module composed of a photon absorption coefficient controller and (HgCd)Te detectors can meet the needs of practical application in some extent.

A simple struture optic fiber interferometer current sensor was designed. The model is given and the feasibility is tested. Compared with other current sensors, this sensor is free of power suppty in high voltage side, with a large measuring range and is not sensitive to slow variable such as temperature because of its special optic circuit.

The calibration experiment of glancing incidence soft X ray planar mirror reflectivity is reported. The Beijing synchrotron radiation facility(BSRF) 3W1B beam line and target chamber with reflectometer was used. Under the specific operation mode of beam current 35 mA～110 mA, the storage ring electron energy 2 GeV, photon energies 50 eV～850 eV. 50 eV～850 eV energy region was divided into four energy sections. The calibration experiment for reflectivity of 5° grazing incidence Ni planar mirror was done. High sensitivity silicon photodiode without dead layer was used as detector replacing X ray diode during the calibration. Therefore,2 to 3 orders of magnitude of the signal noise ratio are increased, and the calibration region is expanded from 150 eV～270 eV to 50 eV～850 eV. The entire calibration curve for 5° Ni planar mirror reflectivity is given. The values of experiment and theoretical calculation are compared and analyzed.

The polarity of light transmitted in polarization maintaining optical fibers of a confidential telecommunication system is dependent on artificial and environmental interfere to the fiber. The polarity may be taken as sensing parameter to detect in real time the wiretapping to the telecommunication. The threshold of wiretapping detecting is defined by the bend radius of the fiber, the typical value is 8.5 mm.

A curve fit method and fitting results of refractive indexes of Ta 2O 5 and SiO 2 thin films deposited by using ion beam sputtering in Fabry Perot multilayer systems used for optical telecommunication dielectric thin film filters (Mux/Demux) at wavelength 1550 nm are preseted. The sputtering time, deposition rate and optical thickness of each layers of the filters are given. At last, the measured results by means of curve fitting are discussed.