Closed loop wavefront residual error of adaptive optical system consists of the uncompensated turbulence error and closed loop noise. The measured closed loop wavefront residual error is analyzed by using open loop and closed power spectrum. When the system noise is considered, the measured reconstructed phase error and the closed loop wavefront residual error are different. Based on the difference of their power spectrum, a method of evaluating the closed loop wavefront residual error is proposed. The comparison of the reconstructed phase error, which is calibrated in high resolution adaptive optical system of 1.2 m telescope, and the closed loop wavefront residual error is given.

A simple and novel method for transforming a uniform fiber grating into a linearly chirped grating is presented. This method permits independent tuning of the chirp degree and the central wavelength of the fiber gratings. It is demonstrated experimentally that the chirp degree of a 100 mm long uniform grating can be increased up to 0.5 nm/cm and its central wavelength can be independently tuned by 0.7 nm. A transmission experiment for compensating the dispersion of a standard single mode fiber (G652) over a distance of 100 km of a 25 ps input signal in the 1550 nm windows was successfully demonstrated using such a tunable chirped grating of 10 cm in length.

Interaction of two quasi solitons propagated in optical fiber cascaded system and its restriction of transmission capacity and distance is studied by theoretical analysis and numerical simulation. The meticulous transmission process of quasi solitons is analyzed.

The transmission characteristics of Fiber Grating Fabry Perot Cavity have been analyzed theoretically. The analytical expression of transmissivity has been given and compared with ordinary Fabry Perot cavity. The influences of grating length and reflectivity on threshold cavity length for fiber grating Fabry Perot cavity with single mode output have been discussed.

A semi numerical methodstrip distributed transfer function method, is developed to analyze the propagation characteristics of rectangular dielectric waveguides. The fundamental equation of the method is derived from scalar variational equation, and two specific models are given. Numerical analyses of the models are presented and compared with other methods. The results show the advantage of this method.

In order to fully use the resolution of optical scanning hologram system, a method of using circular grating to scan the objects is proposed for producing the optical scanning holograms.The advantages are that the incoherent light can be used to produce holograms and the stability of the optical system is increased as a single path system. The principle of the circular grating optical scanning holography and the experimental results are presented.

Coherent properties for excitons and for free carriers in intrinsic bulk GaAs are studied with femtosecond free induction decay (FID). The GaAs at 77 K is excited at its excitonic energy with dual fs pulses from a Ti:Sapphire laser and the FID is recorded through photocurrent detection. The dephasing rates are determined by comparing the FID with theoretical results for density matrix in homogeneouse brodening two level system.

The principle of position sensitive detector (PSD) is introduced, and automatic determination of the center of the intensity of light spot is analyzed. Various working modes are also outlined. As a main probeam, the unavoidable diffraction of light source in many applications is pointed out. Theoretical analysis of position error caused by diffraction is presented accordingly, which makes it possible to evaluate such additional position error quantitatively and guide the application of PSD.

Based on the theory of geometric optics, the synthesis aberration equation of multibeam scanning and imaging system is derived. The primary factors, such as the angle between the incident ray and the axis of imaging system, the number of the facets of polygon, that cause bow of the off axis scanning line are analyzed, and the weight factor of each single aberration is discussed. The specific scanning lens is analyzed to satisfy the straightness of the off axis scanning line on the basis of synthesis aberration equation of multibeam scanning and imaging system.

The phase matching effect on high order harmonic generation was studied by using a 45 fs 2 TW Ti:sapphire laser pulses, especially the effect of gas density, laser intensity and confocal parameter. It is found that there are an optimal gas density and an optimal laser intensity with regards to the improvement of phase matching. The weak focusing geometry is more favorable for higher conversion efficiency than the tight one.

The experimental results of high order harmonic generation in Ar noble gases using an 45 fs, 785 nm Ti:sapphire laser pulse are presented. The effects of gas densities and pulse intensities on harmonic emission are studied, The harmonic generation up to order 81 (9.7 nm) under optimum experimental condition is observed, which is to date the shortest wavelength hormonic emission in Ar noble gases. Analyses show that the harmonics higher than order 57 are generated from Ar +.

By using the theory of partially coherent light, the analytical expression for the mode coherence cofficients of flattened Gaussian beams has been derived in the cylindrical coordinate system. Furthermore, based on the generalized M2 factor of laser beams which was derived by the authors, the mode decomposition theory of flattened Gaussian beams has been built up.

A new method to fabricate TM pass polarizers by introducing zig zag shaped proton exchanged regions adjacent to a Ti diffusion waveguide on X cut, Y propagation lithium niobate is presented. A two dimension BPM (Beam Propagation Method) has been used to analyse this new kind of polarizer. The performance of the device is shown to depend strongly on the geometrical shapes of the proton exchange regions and their distances to channel waveguide. Through optimizing the parameters, a perfect device have been realized, and a TE extinction of 23 dB has been obtained experimentally.

The sapphire fiber thermometer ranging from the room temperature to 1800℃ is described. It uses a specially grown sapphire fiber as the thermometer probe. The end part of the sapphire fiber is doped with Cr 3+ ion by means of the laser heat pedestal growth (LHPG) method and coated with some high radiant material to constitute a mini fiber cavity. Techniques of fluorescent lifetime detection and the radiance intensity detection were used. Growth of the end doped sapphire fiber is introduced. Analysis is made on the temperature dependence of fluorescence of the end doped sapphire fiber as well as the signal interference between the fluorescence and the thermal radiance. Experimental system of the thermometer and the preliminary experimental result are presented.

A theoretical model of wavelength conversion based on cross gain modulation in a semiconductor optical amplifier (SOA) has been established. The influences of SOA bias current as well as pump and probe light parameters on extinction ratio characteristics of converted signals are discussed. The results show that higher pump power, lower probe power and suitable wavelength spans between pump and probe light wavelengths have the advantages to achieve the higher extinction ratio.

The effect of temperature and argon rare gas pressure on internal photon conversion efficiency (η) in the strontium atomic resonance filter (Sr ARF) has been studied in detail. It is demonstrated that the η is augmented as Ar pressure increased, and an optimal value exists during the variation of temperature.

A new type of frequency doubler is presented to meet the requirement of angle phase matching in the tunable range of Ti:sapphire laser without turning the frequency doubling crystal. The frequency doubler ensure phase matching of Ti:sapphire laser in BBO crystal by dispersive effect of combination system of prisms and lens.

After a simple surveying the development of the speckle camera in Yunnan Observatory, the R&D and the properties of a new speckle camera YOSC 4a time framed 2 dimensional photon counting speckle image detecting system are introduced. The test and analyses for the camera showed that the limit magnitude will be 12 m when it is used to do the observation of astronomical speckle imaging; and some real observation data of speckle images and image reconstructed results are given.

A novel magneto optical modulator is presented. This kind of modulator can effectively reduce the temperature rise and thus reduce the magneto optical drift. Its performance is demonstrated in the polarization test, and the measuring resolution of 3.3×10 -7 rad and the long term stability error of 1.7×10 -6 rad are achieved.

The effect of virtual photon field in the Kerr like medium on the photon statistical evolution of one excited three level atom was investigated. The results show that the quantum noise of the photon statistical evolution is caused by the virtual photon field, the quantum noise becomes weak gradually while ω increases, and disappears while ω approaches threshold. The amplitude of Rabi oscillation increases and the frequency becomes higher while λ increases, and the quantum noise simultaneously becomes strong. On the other hand, the amplitude decreases and the frequency becomes slower while μ increases, and the quantum noise simultaneously becomes weak.

Two mode SU(2) coherent state of the cavity is prepared by a parametric frequency conversion process. Then atom cavity field entanglement is created by atom field Raman interaction, and atom field state collapses into two mode SU(2) Schrodinger cat states through atomic selective measurement.

The properties of phase evolution of light in the intensity dependent coupling Jaynes Cummings model with surrounded Kerr medium are investigated by using the pegg Barnett phase theory. The results show that the atom field coupling constant ε and Kerr medium field coupling constant χ will lead to increasing phase quantum fluctuations of light, and the frequency of the field will shift when atom is initially at the non coherent excited state.

A green thin film electroluminescent device using ceramic thick film as insulating layer has been manufactured. The transparent layer is ZnO doped with Al made by sputtering and the luminescent layer is ZnS:Er, Cl made by electron beam evaporation method. The dependence of brightness on voltage was measured as well as the dependence of efficiency on voltage.

Soft X rays of “water window” waveband is very beneficial to the study of hydrated biological materials. The theoretical basis, experimental setup, experimental results and its significance of the soft X ray microimaging in helium environment are described. The study is made at Soft X ray Microscopy Station, NSRL.

The application of frequency modulation and magnetic rotation techniques to the velocity modulation spectroscopy is presented for detection of molecular ions. This technique not only keeps the advantage of successfully suppressing absorption signal from neutral molecules, but also possesses the feature of reducing the background noise to the quantum noise limit.

A model of the photon avalanche in a four level coupled system is proposed. The general condition to generate the avalanche has been theoretically analysed. The avalanche threshold and the temporal behavior of the avalanche fluorescence intensity when the pump rate is below or above the threshold are discussed in details. Then this model in combining with the numerical approach is applied to the case of Tm3+:LiYF 4 crystal. Theoretical results agree with the experiment on the whole. This model and the obtained results are helpful for developing new type avalanche upconversion materials.

Up to now, almost all conventional cathode ray tube (CRT) colorimetric prediction models are based on the “superposition principle of tristimulus values”. Through a series of experiments. It is found that there exists a kind of “suppressive effect” among RGB channels in practical CRTs, and this effect will invalidate the superposition principle and result in the interactive errors in conventional CRT colorimetric prediction models. The experimetal results show the errors caused by this “interaction effect” will increase with the luminance values on the CRT screen.