An improved WKB equation for inhomogeneous planar waveguides considering both the first order reflections between layers and the real phase shift at a turning point has been developed by using the transfer matrix technique. The numerical comparison demonstrates the accuracy of our method. The improved WKB equation can also be applicable to the mode close to a turning point or a dramatic index variation waveguide.

Based on the dynamic behavior of the acousto optical bistable system driven chaotically, a secure communication system is proposed. It can be realized by adding message due to the phase property of the system and extracting message due to the chaotic signal produced by chaos driving at the receive end. It is found that message can be securely transmitted even the signal masked by large noise. The message recovery needs no chaotic signal perfectly synchronized with carrier but only depends on the correlation of transmitted signal to the output signal of driven system at the receive end. The scheme is praticable in application.

We present a new volume holographic data storage architecture which consists of two photorefractive crystals storing exactly the same contents. Without a phase conjugator, the new architecture is capable of fast self enhancement of the stored gratings by using two temporally modulated plane waves. The effects of the modulation rate, reading beams′ intensity ratio, initial fixed grating strength and the crystals′ nonlinear coupling strength on the enhancement speed and steady state diffraction efficiency are discussed.

We realized hologram storage within 0.07 cm 2 light spot in thin layers of polyvinyl alcohol (PVA) matrices doped with methyl orange dyes (MO), pre irradiated by the 488.0 nm line of an Ar ion laser using two orthogonal linear polarized 632.8 nm light beams. By rotating sample, multi hologram storage was achieved. By controlling writing time, three hologram images have been recorded in the same light spot. The mechanism of the multiple hologram storage in MO/PVA thin film was discussed using a four energy level model of MO molecular in PVA materices.

A novel fiberoptic sensor array with the shape of bamboo node is presented which is made of periodically etched multimode optical fibers and can be used for smart material and structures. An artificial neural network is applied to processing of parallel and distributing optical fiber array sensing signal in smart material, and to get the structure state such as dimension and location of stress, strain or damage in smart material and structures. The simulation results of BP network are given.

The perturbative theory of laser induced collisional charge exchange (LICCE) is presented, in which the laser induced collisional charge exchange is described as a four body system and the compound atomic and ionic states are used as basis states of LICCE, and the equation of motion for the probability amplitudes of the states are obtained. The numerical results of LICCE in Ca + Sr are obtained for the first time through numerical calculation, and the comparison between the theoretical results and the experimental one (obtained by W. R. Green et al.) confirms the interpretation of the peaks at 477.0 nm as due to LICCE in Ca + Sr and the peaks at 471.5 nm due to LICET in Ca Sr system.

By using KTP nonlinear crystal as extracavity frequency doubling and combining stimulated Raman scattered (SRS) technique in a CPM unstable resonator Nd:YAG laser, the ultrashort pulses at three different wavelengths of 1.06 μm, 0.53 μm and 0.63 μm are obtained.

Dependences of ground state absorption and excited state absorption of Cr 4+ :YAG upon fluence and intensity of input laser pulses are calculated based on the rate equation. Measuring transmission of this crystal, we discovered that its excited state absorption tended to be saturated. Key parameters are obtained by matching the theory calculation with experimental data. The Nd:YAG laser with 5 ns pulsewidth was operated and found which is directly relevant to excited state absorption saturation of Cr 4+ :YAG .

The lock in effect and threshold expressions caused by backscattering from cavity mirrors in a passive resonator gyroscopy are derived based on the resonance characteristics of cavity. The experimental observation proves the results of theoretical deduction.

An effective methods for measuring ultra high reflectivity by comparing the loss between two active optical resonators is presented. The basic principle of this measurement comes from the Fresnel formula and Brewster′s law. The measuring accuracy is ±5.0×10 -5 and the problems of the measuring system are discussed.

The nonlinear optical properties of Ru complexes and coordination compounds were studied by degenerate four wave mixing (DFWM) measurements at 450 nm. The third order nonlinear optical susceptibility and the third order hyperpolarizability were measured. The third order hyperpolarizabilities of coordination compounds and substitution groups were qualitatively and quantitively discussed. It is found that substitution groups signifiantly enhanced the γ value.

The coherence time measurement of laser pulse was studied by using counter running pump probe technique in two photon absorption materials. The coherence time of 23 ps, 532 nm laser pulses was measured. The experimental results and theoretical analysis show that additional two photon absorption arises from two beam coherence effect. This method can be applied to other pulse width laser measurement.

A novel KTP electro optic deflector with diameter D=4 mm, length L=40 mm, is designed. Compared with the same size LiNbO 3 deflector, the temporal resolution of KTP deflector is 180 ps, while LiNbO 3 deflector is 414 ps. The shaped laser pulse with the least width of 400 ps of KTP deflector and 830 ps for LiNbO 3 can be obtained respectively. Factors affect the property of electro optic defector are analyzed. Using a temperature controlled oven, the wave front distortion in laser pulse propagation can be eliminated.

Using the reaction of the crosslinking of ammonium dichromate gelatin after irradiation, a novel microlens array was fabricated. The optimum technology of making gelatin microlens array was discussed. The specification data of the array were presented.

A new projection technique for measuring the intensity undulations by interference speckles caused in the micrometer magnitude has successfully been developed, in order to test the focal property of optical array system for uniform illumination. The experimental method, measurement results and error analysis for testing the large scale non uniformity of 1 D and 2 D focal spot and interference speckles of the small scale have been presented.

On the basis of analyzing the characteristics of image formation of image rotator prisms, a method of using a mirror assembly for image rotator is suggested. It is theoretically proved that this mirror assembly can be applied in kinds of optical systems with different wavelength range, especially suitable for working in infrared system.

A novel sinusoidal phase modulating laser diode interferometer based on slowly varying approximation is proposed and demostrated. It is not necessary in principle to keep amplitutes of the first and second harmonic components equal in expriment, and dynamic range has been inrceased 3￣4 order. A PZT and Picomotor are used as displacement actuator to detect the resolution (or accuracy) and dynamic range. The accuracy is 5 nm when the displacement drived by PZT exceeds a half wavelength of the light. The maxmum displacement measured is more than 1 mm. This system can complete real time and auto measurement under noise circumstance.

A new optical profilometry linearly coded profilometry is presented. It uses a periodic linear structure illuminating light to code the surface and the phase shifting technique to decode the phase. The principle of linearly coded profilometry is discussed in detail and the reliability is verified by the experiment results.

Based on the modulation ordering, a novel phase unwrapping algorithm for measurement of photoelastic fringe orders in the whole field of a model is put forward. The path for phase unwrapping is determined by the intensity modulation in the pixels on the boundary of the phase unwrapped areas. The algorithm is very superior, and in the worst case the error, if any, is limited to local minimum areas.

The reduction of the Hamiltonian for a three lvel atomic system in a Ξ configuration to an effective two level one and the relative physical effects are discussed both with and without the rotating wave approximation.

X-ray Gabor in line holograms of wire-like object is recorded in photoresist. After enlarged to film by microscope and digitized by scanning microdensitometer, the holograms are reconstructed by using numerical methods, and the origin objects can be clearly observed in the image plane. The 3.2 nm soft X rays used in experiments are the bending magnet radiation of a 800 MeV electron storage ring and have been monochromatized by linear monochromator. The estimated resolution of the reconstructed images are better than 2 micrometers and remains to be improved in the future.

A diagnostic technique utilizing infrared transmission spectroscopy for calculating the ratio of SP2/SP3 bonds in diamond thin films is presented. This method allows a quantitative assessment of the quality of films, even when analysis of Raman spectra would give ambiguous results because of sensitivity limitations. Sample calculations comparing two diamond films and amorphous carbon are presented.

The transition mechanism and “abnormal” temperature effect of 5D 0 - 7F 0 transition of Eu 3+ in EuCl 3·6H 2O are studied. By analysing the intensity ratios of the 5D 0 - 7F 0 transition to the lowest energy level line of the 5D 0 - 7F 2 transition of fluorescence spectra at different tempertures, it is found that 7F 2 state (mainly the lowest energy level) can couple with 7F 0 state by four 245 cm -1 phonons. The 7F 0 state becomes a mixed state, so the “forbidden” 5D 0 - 7F 0 transition can be allowed and its oscillator strength varies with temperature. Therefore, the transition mechanism and the relationship between the oscillator strength of 5D 0 - 7F 0 transition in EuCl 3·6H 2O and temperature are well explained.

The Raman spectra of the solid C 60 at 284～10 K were measured, and the intensity temperature curves were illustrated. For all these curves, the mutation appeared at the first order phase transition temperature 250 K. The intensity and its variation of A g mode were higher than that of H g. For the curves of 1470 and 498 cm -1 , its fluctuatory tendencies were opposite, one was rising just other was decreasing. It is considered that the radial vibrations were the major motions for inner mode vibrations of molecule, and there were some competitive function between two A g modes. The nonlinear optical effect near phase transition temperature would br more obvious.

The photoionization of Be like Ar ion inner shell electron is studied. We have calculated its high levels, radiation life time, radiation rate, wavelength and oscillator strength as well as the “water window” wavelength.

The characterization and the variation relation of the phase to the wavelength are analyzed for the multilayer coatings. The phase variation of the HR films was calculated and the influence of the phase of coatings on optical devices was investigated.