A discrete time transmission model is proposed to characterize the response of fiber gratings, and the digital processing methods are used to analyze the phase response of fiber gratings. The inner band dispersion characteristics of apodized fiber gratings used for DWDM filtering is studied. It is shown that the amplitude and phase responses of symmetrical apodized fiber grating are related by means of the Hilbert transform, the closer to ideal rectangle the amplitude response is, the greater the inner band dispersion is. The coupled mode theory is used to calculate the reflection phase response and inner band dispersion of apodized fiber gratings, the above analysis is verified.

Compared to existing cone beam computerized tomography (CT) techniques, the reverse geometry based cone beam CT (RGCBCT) can provide projection data with considerably higher SNR, and is convenient in the implementation of exact reconstruction. A novel orthogonal circle and arc orbit for cone beam CT is proposed. Its completeness condition and the application of the Grangeat method are discussed. A flexible orthogonal circle and arcs orbit for RGCBCT together with its completeness condition is proposed. Based on the equivalence between the reverse and traditional imaging geometries, a reconstruction algorithm for RGCBCT and computer simulation results are presented.

Fluorescence power transfer function, three dimensional point spread function (3D PSF) and three dimensional optical transfer function (3D OTF) for the various fluorescent wavelength are calculated. The results show that the fluorescent wavelength has influence on imaging property of confocal microscopy such as spatial cut off frequency, resolution and 3D OTF. There is a missing cone in the 3 D space of OTF when the ratio of excitation wavelength to fluorescent wavelength decreases.

Characteristics of the f θ lens system based on diffraction alignment technique are analyzed, thereafter a novel diffractive long trace profiler (DLTP) for large aspherical optics, especially for those optical component used in synchrotron radiation, is introduced. Details of the DLTP such as the principle of its optical subsystem, characteristics of the diffraction pattern, data processing methods are investigated. A prototype of the DLTP has been developed, its scanning range is 370 mm, and the slope resolution is better than 0.25 μrad. Experimental results show that the prototype has excellent stability and precision even in rather poor circumstance without temperature controller and air condition, and the measurement stability is about 0.7 μrad/200 s, measurement precision within whole scanning range is 1.14 μrad.

Signal to noise ratio and signal to background ratio are crucial factors for a confocal scanning fluorescence microscope to form high contrast and resolution images of thick tissues because of the low signal level and multiple scattering processes. So the suppression of stray light is very impertant. Based on the concept of information capacity and the results of the calculation of the signal to noise ratio and the transfer function of a confocal scanning fluorescence microscope, the relationships among the information capacity, signal to noise ratio and 3 D optical transfer function are analyzed. The results obtained is very useful for development of a confocal scanning fluorescence microscope.

The phase conjugation effect and the threshold effect of stimulated Brillouin scattering (SBS) on the divergence angles of back SBS were discussed in the theory. In the experiment, the active medium and wave front aberration generated by optic component were compensated, the divergence angles were compressed, and the beam quality was improved by using the SBS PCM to replace the ordinary reflector in the Nd∶YAG polarex. The pumping energy, lens focal length affecting the beam quality of the SBS polarex were studied.

In this paper, we present a new kind of coupling technology which use amicro prism to sided coupling LD pumping energy into double cladding fiberefficiently. The mechanism and the application method was first introduced, then the theoretical coupling efficiency was given (about 90%). Finally, therequire ment on the LD source and the application limit of this technolog was givenbased on the analysis.

The characteristic properties of type Ⅰ (e→o+o) nocollinear phase matched LBO (LiB 3O 5) optical parametric chirped pulse amplifier are investigated. A theoretical model of noncollinear phase matched parametric process in LBO is presented. Using the numerical method, the analytical formulation for the parametric efficiency coefficient, effective gain, parametric bandwidth, gain bandwidth of the amplifier are obtained. The numerical simulation results demonstrate that not only the high gain could be obtained in this amplifier, but also the broadest gain spectrum bandwidth could be attained. It provides a great potential to efficiently femto second light pulses to generate new extremes in power, intesity and pulse duration.

An opto electronic feedback loop with AM was used to suppress the laser intensity noise. The opto electronic feedback loop was analyzed theoretically and then we experimentally suppressed the intensity noise of LD pumped single frequency ring Nd∶YVO 4 infrared laser by using the feedback loop. The result indicated that the intensity noise is reduced greatly between 0～1 MHz frequency with the maximum reduction 15 dB.

Several techniques of femtosecond pulse spectrum broadening in the chirped pulse amplifier of femtosecond laser are reported, and a few spectrum broadening elements are used. The results show that the spectrum of femtosecond pulse laser can be broadened effectively by using the laser spectrum broadening elements, and at some extent the spectrum gain narrowing effect of laser pulse can be effectively suppressed in the femtosecond laser amplifier. The seed pulse output of 28 fs is obtained from the oscillator in the femtosecond amplifying system. After amplification, an ultrashort ultra intensity laser pulse with the repetition rate 10 Hz, peak power 1.6 TW, pulsewidth 37.5 fs is achieved.

The effect of amplified spontaneous Raman scatting on the Raman amplifier on off gain is studied and a method to adjust the flatness of Raman amplifier on off gain by the spectrum of ASE is proposed. Four 14xx nm laser diodes were used as pump source, 75 km G.652 fiber as transmission medium, and obtained the amplified light of C band in the experiment. Theoretical explanation is presented.

A (Tm,Ho)∶YLF microchip laser pumped by a CW Ti∶Al 2O 3 laser and tuned to 792 nm is discussed. At room temperature, the laser output power of 90 mW is obtained when pumped by 680 mW power. The laser threshold is about 390 mW, the optical optical conversion efficiency and slope efficiency are 13% and 26% respectively.

AuGeNi InP alloy on InP chip and good ohmic contact have been fabricated by means of laser assisted alloying. The minimum contact resistance between the two surfaces of InP substrate is as low as 5.8 Ω. According to the experimental result, influence of some important processing parameters (as alloying time, alloying temperature, the thickness of film, et al.) on ohmic contact are discussed.

The effects of crystallization fraction on the optical constants of Ag 11 In 12 Te 26 Sb 51 phase change films were studied. The phase change thin films were crystallized using initializer and different crystallization fraction was obtained by changing the initialization parameters. With fixed initialization velocity, the refractive index decreases and the extinction coefficient first increases then decreases when the laser power increases. With fixed initialization laser power, the refractive index increases and the extinction coefficient first increases then decreases when the initialization velocity increases. The changes between amorphous phase and crystalline phase, the changes in microstructure (including changes in crystalline phases and the bonding state), and the internal residual stresses in film are the main factors influencing the complex refractive index of Ag11In12Te26Sb51 phase change film. The transmissivity of single Ag11In12Te26Sb51 film and reflection spectra of the Ag11In12Te26Sb51 film in CD-RW phase-change optical disk at amorphous and crystalline states were measured.

The defect states in two dimensional amorphous photonic materials composed of dielectric cylinders are calculated by using a multiple scattering method. The simulating results show that the frequencies of the defect states are different from each other when various cylinders are removed, meanwhile the energy of electromagnetic wave is almost localized in a circle whose radius is less than one third of the defect wavelength. These reveal that the defects of the amorphous photonic materials have the same property as the defect of a periodic photonic crystal for the case of strong energy localization, furthermore the defect modes in the amorphous photonic materials are richer than in the periodic photonic cyrstal.

The structure, fabrication technology and light emission properties of double barrier MIMIS tunneling junction are discussed. It shows better characteristics in comparison with MIS junction. The maximal luminance of the MIMIS devices is 1.9 cd/m 2, and their sprctrum peak appears in the blue area. The phenomena can be well explained according to resonant tunneling theory.

The high order harmonic emission from thin plasma foils irradiated by two circular polarized, counter propagating laser pulses with their electrical vectors rotating in different direction was investigated via 1\|D particle in cell (PIC) simulations, More than 200 harmonics can be generated with the laser intensity of 10 21 W/cm 2. When the duration of laser gets shorter, the frequencies of harmonics were severely modulated due to the Doppler shift caused by the movement of the plasma boundary when the foil is being compressed. The Doppler shift can be estimated by the simulation results, and this effect can also be reduced or modified by introducing frequency chirping to the pump pulse.

Based on index ellipsoid equation and characteristics of optical wave propagation and polarization in a biaxial crystal, methods of the collinear phase matching (PM) permitted for frequency doubling in principal planes of biaxial crystals are discussed and analysed. The general expressions of the effective nonlinear coefficients d eff and phase mismatchs for all the allowed PMs are derived for all kinds of biaxial crystals. By using the Table, in which possible PM types or polarization combinations, respective PM angle formula and effective nonlinear coeficients are involved, realizable PM methods may be found and respective PM angles can be calculated. Finally effective nonlinear coeficients for allowed PMs can be compared and optimal PM types or directions can be selected easily.

Zernike modal wavefront reconstruction algorithm was used commonly for Hartmann Shack sensor in circle apertures. Formulas to calculate the modal wavefront reconstruction error of Hartmann Shack sensor in general condition were deduced. An aberration plate containing random static wavefront aberrations was measured with a Hartmann Shack sensor and a ZYGO interferometer respectively, then the modal wavefront reconstruction error of Hartmann Shack sensor while using different Zernike polynomials was obtained. The experimental results were analyzed and compared with theoretical calculations.

A new optical fiber sensor developed for simultaneously measuring the seawater temperature and salinity is described. The sensor respectively exploits the displacement of the optical absorption edge in semiconductors under the influence of temperature variation as a result of temperature induced energy shifting of conduction band extrema, and the beam deviation caused by the optical refraction at the receiving end face due to the salinity of seawater. The measured optical signals are reflected and transmitted through a sequentially linear arranged fibers array, and then the light intensity peak value and its deviant are detected by a charge coupled device (CCD). The sensor probe is composed of an intrinsically pure GaAs single crystal,a right angle prism, a partitioned water cell, the emitting fiber with an attached self focused lens and the linear arranged receiving fibers array. Theoretical analysis and simulations verify the feasibility of the proposed system.

The principle and design of a cat′s eye made of two glass hemispheres are described. It shows that cat′s eye becomes a whole sphere when the glass with refractive index of 2 is used. The optical path analysis, indicates that the offset between two hemispheres (including the thickness error of the glue) play an important role in the final accuracy of the laser tracking interferometer. The relation between divergence angle of the reflected rays, radius of the hemispheres, refractive index and incident height of the entering rays is discussed. The parameters of cat′s eye are optimized to get the least divergence angle of the reflected rays, and the optimal parameters are given.

A head mounted display, which combines a Erfle eyepiece with a reflective relay system and uses a micro display of the reflective liquid crystal on silicon with the diagonal size 18mm, has been designed. The sign of the field curvature, either the sagittal or the tangential, of the relay system is on the contrary to that of the eyepiece, which makes the system possess smaller field curvature and astigmatism. The adoption of the relay lens makes the system not only suitable for the micro display with smaller size but also offering enough space for light source in the reflective micro display. The system is with smaller aberration, enough exit pupil diameter and eye relief, and reasonable size and weight in the specific application of head mounted display.

BaTiO 3 crystal was precipitated in BaO TiO 2 SiO 2 based glass irradiated by femtosecond laser with 800 nm wavelength, 120 fs pulse duration and 200 kHz repetition. During the irradiation, the luminescense color of irradiated point can be changed from 800 nm wavelength characterized red color to blue color. Luminescence spectra and X-ray diffraction of the irradiated point illustrate the formation of double frequency BaTiO3 crystal in the glass.

The influences of the main parameters on population inversion including initial population of the ground state, statistical weights ratio of the lower and upper laser levels, ratio of the three body recombination cascade speed and the spontaneons radiative decay speed are calculated and studied by using numerical calculations. The practical system is analyzed and discussed, with an example the recombination pumping B like N 45.21 nm 3s 2p system based OFI (Optical Field Ionization). The results including the optimal laser intensity to realize B like N 45.21 nm 3s 2p laser amplification are presented.

Third derivative saturation absorption spectrum of cesium D 2 line is demonstrated via the third harmonic technique, under the condition that the frequency modulation is applied to a external acousto optical modulator. By using this undithering scheme combined with the technique of third harmonic locking, frequency of a 852 nm DBR diode laser is locked to the hyperfine component of cesium 6S 1/2 F=4→6P 3/2 F′=5. A frequency jitter of less than ±350 kHz in 10 s and the frequency stability of about 1×10 -9 are estimated based on the error signal after locking in the preliminary stabilization. This locking scheme without frequency dither can avoid the extra frequency noise resulted from direct frequency dither on diode laser in normal saturation absorption technique, and application of third harmonic technique can strongly reduce the residual Doppler background.

Strontium barium niobate thin film was successfully deposited on MgO(001) substrate with the sol gel process, the film thickness was up to 5 μm. The film microstructure was studied by the methods of X ray diffraction, X ray rocking curve,  scan, as well as Raman scattering spectroscopy. The results show that the SBN thin films have the (001) preferred orientation, and the SBN tetragonal phase with enhanced (001) orientation were observed in thicker films. A very large value of 6.62×10 -11 m/V of effective transverse electro optical coefficient for the SBN film deposited on transparent fused silica substrate was measured.