Through the study on the advantage and defect of current distributed optical-fiber sensors (DOFS), a new type of DOFS entitled soliton DOFS is proposed based on Raman backscattering. We studied the effect of high-order soliton, the property parameters, and the possibility and difficulties of realization based on the optic and electronic components available.

The relation between the coupling efficiency of the compound parabolic concentrators (CPC) to multimode optical fibers and the design of the concentrators are discussed. Two methods, the botton-truncation and the top-truncation, are proposed to increase the coupling efficiency between the concentrators and the fibers.

Tomograms of thermal flow field are the information records characterized of fringes. Fringe analysis is a critical step both for interferometric and Moire tomography. How to extract clear and intact fringes from all kinds of noises, especially strongly inhomogeneous background illumination, is the key problem in preprocessing of thermal flow field tomogram. The characteristics of thermal flow field are analyzed and a probability filter method is developed, in which the center of image histogram is corrected, a so-called “extractable probability” is introduced as the standard for identifying signal from noise. According to a projection function determined by image features, gray image is projected into its probability plane where iterative signal enhancing and noise reduction are performed. It is proved that the probability filter presented in this paper is effective to the tomograms of thermal flow field.

The effects of zero-order diffraction spot on the reconstruction images in the digital reconstruction of lensless Fourier transform hologram are analyzed.A method to eliminate the zero-order diffraction spot with digital subtraction and digital reconstruction of hologram is suggested. Reconstructions of hologram without zero-order diffraction spot are implemented successfully. The results are discussed.

Since the spatial distribution of laser beam is taken to be Gaussian, We deduced the point spread functions (PSF) both for the ideal and for the practical optical scanning systems. The PSF is δ function for the ideal case and Gaussian function for the practical case.

A linear discrimination function (d(w, x)=w′x) is presented to classify two aircrafts (the bomber and the fighter) with rotation invariance. There are 72 rotation images (patterns) for each aircraft, in which 9 rotation patterns are used as the training set and the other 63 patterns are used as the test set. The original weights {wij} are obtained by one of the training pattern of the bomber subtracting one of the training pattern of the fighter. To improve the correctly recognizing rate, a modification of the correctly weights is carried out by the wrong recognized training patterns. In order to opto-electronically implement, the weights {wij} only have five values (-2, -1, 0, 1, 2). The results of the computer simulation state that the correctly recognizing rate reach to 95.8%. A opto-electronic hybrid system is presented to implement this linear discrimination function for recognizing the objects with the rotation invariance.

A Haar wavelet transform with a Vander Lugt optical correlator is described. Optical Haar wavelet matched filter is created by using of computer-generated holography (CGH′s). Experimental results for 2-D wavelet transform are obtained. The main advantage of the proposed method lies in that any types of wavelet matched filters can be fabricated and their 2-D wavelet transform can be realized.

By using the nonlinear switching effect of nonlinear optical fiber loop mirror (NOLM) and the saturable absorption effect of bulk semiconductor waveguide self-staring mode-locking of erbium-doped fiber laser has been demonstrated. High stable mode-locked pulses train has been obtained. Harmonically mode-locked pulses have been observed. The nonlinear switching reflection characteristic of NOLM is analyzed.

The characteristics of the multiple-pulse operation of a self-mode-locked (SML) Ti: sapphire laser have been analyzed in more detail. A novel model of the decreased self-amplitude-modulation induced by intracavity periodical scattering is presented. Numerical simulations based on the model give a good explanation to the experimental results.

Based on diffraction integral described by complex matrix for misaligned optical system, we discussed the transport rule of cross-spectral density function of patially coherent beam crossing a complicated optical system. With a novel method and Wigner function, taking soft X-ray laser for example, the output behavior of noncavity laser is analysed. The theoretical calculation and the available experimental results are in agreement.

The stability of a Ti: sapphire regenerative amplifier (RGA) operating at 1056 nm has been discussed, and the stable amplified pulses have been obtained in an experimental Ti: sapphire RGA. The RMS of the pulse energy is less than 5%.

The possibility of using Cr4+: YAG as saturable absorber to achieve passively mode-locked operation in a Nd: YAG Laser is proposed theoretically. From the rate equations, we derived the resumption time and the saturable light intensity of the excited-state of Cr~4+: YAG acted by strong laser pulses. Passively mode-locked operation is experimentally realized by using Cr~4+: YAG as saturable absorber in a pulsed Nd: YAG laser with a nearly critical stable resonator and an antiresonant ring. The pulse train with energy of 13.5 mJ and pulse duration of 180 ps are obtained.

Coupling losses of planar waveguide resonators are discussed in terms of angular spectrum theory. Under the conditions given in the paper, the EH11-mode coupling coefficiency is calculated numerically. The conclusions can be applied to the other modes.

The instability characteristics of a He-Ne laser with plane mirror and self-pump phase conjugation feedback are studied. The effects of distance between the feedback mirrors (plane mirror or phase conjugate mirror) and laser on the laser intensity fluctuation and fluctuation frequency are abserved. We find that laser intensity has large fluctuation and quasi-periodic oscillation of seconds order when the feedback mirror is at integer multiple of half cavity length. Its mechanism is analyzed.

Based on the investigations of Thomson scattring of moving electrons in the presence of oncoming electromagnetic radiation, two new schemes for obtaining short wavelength electromagnetic radiation have been discussed. One of these is to use the harmonic polarized frequency up-shift by the nonlinear Thomson scattering of ultraintense circularly laser from the electrons with a certain velocity. Another is to use the Doppler frequency shift by the opposite direction scattering of ultraintense laser from the relativistic electrons.

When cylindrical symmetry is assumed, a numerical study of coherent on-resonance propagation of laser pulses in atomic media has been done based on the coupled Bloch-Maxwell equations. The spatial-temporal evolution of the laser pulse was studied in consideration of both the self-induced transparency and diffraction. The numerical results show that the pulses display complicated coherent phenomena.

The spectra and reflectivity of stimulated Brillouin scattering was reported in laser-plasma. When the different material targets were irradiated by laser with low energy and short pulse, the spectra of SBS were the same. The reflectivity of SBS energy was mainly affected by the size of plasma. The reflectivity of SBS will decrease when high Z material targets were irradiated.

Impulse coupling coefficients from a 1.06 μm, 10 ns Nd: YAG pulsed-laser radiation to HgCdTe targets with different area were measured using the ballistic pendulum method in the laser power-density range from 4.0×10~8-5.0×10~9 Wcm~-2. In theory, a detonation model of the plasma was established and the expansion process of the plasma after the laser pulse end was described in detail. Moreover, impulse coupling coefficients from pulsed with different energy to HgCdTe with different area were calculated by using the model. It is found that the theoretical results agree well with the experimental data.

An efficient green laser has been relized by external frequency doubling of a LD pumped single longitudinal mode Nd: YAG ring laser in MgO: LiNbO_3 resonator. The maximum green power is 330 mW at IR input power of 440 mW, resulting in an external conversion efficiency of 75%.

The influence of pump beam quality on Raman generator at low pressure is discussed. The experimental results of energy threshold, output energy and beam divergence of the first Stokes are present. The quality of pump and the first Stokes beam is analyzed using the M 2 concept. The energy threshold of the first Stokes is calculated according to an approximate theory including the effect of focused pump beam and beam quality. The results are compared with experimants and theory in related references.

Effects of the mixed aggregates of different active materials on optical properties of LB films have been investigated by UV-visible absorption, π-A isotherm and second harmonic generation (SHG) measurements. The chromophore interactions change the optical nonlinearity of LB films via variations in the excited state energy and average electric dipole moment of molecules.

We use femosecond laser pulse to study the fringe variation on the spectrum of pulse due to F-P effect in PPQ organic polymer film. By changing the pulse peak intensity, the fringe variation is observed evidently, while fringe variation is not observed at broadened pulse duration and the same average power. It shows that the thermal effect is no greater contribution to the refractivity, the main reason that leads to fringe variation on the spectrum can be attrivuted to the nonlinear refractive index change of PPQ film due to high pulse peak intensity.

Stimulated Brillouin scattering (SBS) in optical fiber limits the maximum launch power of Am CATV externally modulated transmission system, for the reason it must be suppressed. The authors present the theoretical analysis on laser dithering and give the formula of SBS threshold increased by employing this method. The experimental result agrees well with the formula.

The properties of phase evolution of spontaneous emission in the k-photon (k>2) Jaynes-Cummings model are studied by using PB phase theory. The phase probability distribution and variance are calculated. The curves of evolution of the phase probability distribution are given on a polar diagram.

By means of time-evolution operator, the emission spectrum of a Λ-type three-level atom interacted with a single-mode cavity field was studied. The physical spectrum expression of radiation emitted by the atom is given. The spectrum shows the symmetrical six-peak structure. We have discussed the structure of the emission spectrum for the input in pure number state, a coherent input and a thermal input.

The dtnamics of a two-level ion at the antinode of a standing wave was described with the Jaynes-Cummings model by Cirac et al., In this paper, we will extend this conclusion. With the dressed state, we show that a single two-level ion in the arbitary position of a laser standing wave can be dscribed by the well-known Jaynes-Cummings model.

We present a novel method for phase correction by using binary optical elements (BOEs). This method considerably simplifies the structure of the system and decreases its size and weight. This is a typical application of binary optics in modern optical system. In the phased array system, we use binary phase corrector to correct the residual wavefront aberrations. The BOE has eight steps. The experimental result shows that this element decteased the wavefront aberrations to half of the original value.

The phase retardation expression of ordinary and the extraordinary light in birefringence crystal is discussed.The common used expression is expanded a suitable fitting expression and the relations between its coefficient and the birefringence index are obtained. The use of the fitting expression is given. It can be a principle for designing liquid crystal and the pretilt angle tester using the method of crystal rotation.

A general method for the design of a two-dimensional concave grating with stigmatic points is presented. The construction of gratings with three stigmatic points is given. The image quality versus the dispersion and the grating width are analyzed in detail.

The properties of SrS(Eu, Sm) electron-trapping thin film grown by elctron beam evaporation are studied. The X-ray diffraction pattern, microstructure measuered by atomic force microscopy, optical spectra and the stored image are presented. The results show that the electron-trapping thin film has good optical properties and can be used in optical storage and information processing.

The concept of transition cross section is re-examined in two-photon process. The rate equations and the relevant transition cross sections are good approximation in the region where the diagonal elements of the density matrix change slowly with time. The rate coefficients are derived explicitly:those describing formally the single photon process will be subject to a significant modification for strong light field compared with that of the weak laser field and those describing formally the multi-photon process can also be constructed from the parameters relevant to the real single photon process. The optimization of power distribution of laser fields changes dramatically from weak to strong total laser intensity available. To describe the interference effect originated either from the multi-mode laser field or from a group of energy levels located closely needs more complicated computation of the transition cross sections than using the Bloch equations directly.

The practically measured Fourier infrared absorption spectra of heroin and opium have been given. On the basis of the absorption peak sites, the fundamental phonon energies of heroin are calculated: ELO=0.0486, ETO1=0.0555, ETO2=0.0616, ELA=0.0257, ETA1=0.0097, ETA2=0.0134 eV. All of the Fourier infrared absorption peaks of heroin, consist of these elementary phonons by different combination.

The pump-probe method was used for measuring the transient change of optical transmissivity of metal particle-matrix composite thin film Cu-Ba-O exposed to ultrashort laser pulses. The phenomenon was observed that the optical transmissivity in the thin film rapidly decreased and then recovered in a few picoseconds. The optical relaxation is a process in which nonequilibrium electrons, excited by laser pulses and originating from near Fermi level in Cu ultrafine particles, return to the equilibrium state. An amended theoretical value of electron-phonon coupling constant g of Cu ultrafine particles in the composite thin film was given.

In addition to using the aberration correction theory, optical distortion can be corrected with the digital image processing technology. This is suitable to some optical system such as the optical system for endoscope and machine vision, which distortion is difficult to be corrected through normal optical method because of some kind of limitation. Firstly, We discussed the correcting theory by the digital image processing technology. Then, the correcting method was introduced. To assess the accuracy, we analyzed the source of the correction error. And the correction evaluation were proposed to measure the error.

A 8-channel wavelength-division-multiplexer (WDM) has been fabricated by using 3-stage cascaded 7 single-mode fiber Mach-Zehnder interferometers. The device not only keeps the merit of super narrow-wavelength spacing but also eliminates the drawback of channel number limit for an individual Mach-Zehnder interferometric WDM. The principles, design considerations and manufacture techniques are described. The experimental sample tested offers 2.4 nm wavelength division spacing and 1.5 dB total insertion loss at 1.5 μm working wavelength.

According to the spectral feature of the signal generated by the multiplexed fiber Bragg grating (FBG) sensors, image spectrometry is proposed to demodulate multiplexed signal. The principle of the dumultiplex is analyzed and the main features, such as sensitivity of measurement and the multiplexing capacity of the system is derived. The experimental setup and results are presented.

A kind of high-performance helical-core fiber used in sensing systems of large current or strong magnetical field is fabricated. Its specifications of pitch, core offset, beatlength and loss are 1.5 mm, 255 μm, 3.5 mm and less than 0.5 dB/m, respectively.

The existence of critical angle seriously limits the range of microlens array′s numerical aperture and the improvement of the quality of the microlens in the fabrication of microlens array by using heat-forming photoresist method. Based on the study of the critical angle effect, a new method named step heat-forming photoresist method to expand the N.A. range of microlens array is presents. The results show that this method can effectively improve the conventional heat-forming fabrication. The available diameter range of microlens is from 50 μm up to 900 μm. A series of MLA with F/1 to F/10 relative apertures have been fabricated, with the improved quality of the profile.

According to the operating principle and characteristic of pentagonal prism, it is analyzed that the fabrication error of the prism angles and the effect of lateral displacement of exit beam when the prism has a motion relative to the incident beam on the accuracy of the datum plane to be established. The Fresnel diffraction imaging technique is used to eliminate the effect of the lateral displacement and data calculating is used to calibrate the fbrication error of the angles.