Room temperature CW vertical cavity surface emitting lasers were fabricated by tilt ion implanting and optimizing ion distribution around the active region. The device, whose threshold current was as low as 1.4 mA, gives the maximum more than 1 mW light power.

A high-powered tunable Er-doped fiber ring laser, based on FBG (fiber Bragg grating), is reported in this article. It was pumped by 980 nm-laser diode. The line width of the output laser was less than 0.04 nm in 1562 nm band, and the tunable span was 4.6 nm. The reappearance error was less than 0.08 nm. By way of the selection of the optimum length of the Er-doped fiber and the introduction of the double isolators, the signal to noise ratio was improved. As a result, the maximum output power of the laser was 4.28 mW, while the stability of the power was 0.03 dB, and slope efficiency was 7.3%.

The optimized dye cell length and the partition of pump laser energy between two dye cells in small signal two-stage dye laser amplifiers were numerically analyzed using the transversely-pumped steady-state theory. A computer program was written to find the optimized values of partition of pump laser energy and length of dye cell for a given set of parameters.

980nm vertical cavity surface emitting laser had been fabricated, and the pulse operation with high output power had also been realized at room temperature (24℃). With 5/1000 duty cycle and 50 μs pulse duration, the maximum optical output power was 380 mW for 400 μm diameter device. The divergence angle was less than 10°, and the FWHM of lasing spectrum was 0.8 nm.

Theoretical model is established to study the effects of rotating window irratiated by high energy laser output. Laser induced thermal profiles and stress profiles are obtained by numerical computation.The results show that window rotation causes the axial symmetry of thermal stress, therfore the maxium tensile stress can decrease and the window can endure much more laser output if appropriate rotation mode is chosen. At last, the application perspective of rotating laser window is outlined.

In this paper, the design of coating system, choose of materials, technology of fabrication, as well as the experimental results for the damage threshold and thermal deformation of the cavity mirrors of DF laser are reported. The experimental results show that the thermal deformation of he cavity mirrors of DF laser is about 0.3λ (λ=632.8 nm) under the power density of 21 kW/cm 2, and the damage threshold of the cavity mirrors of DF laser is higher than 40 kW/cm2.

The coupling between the motion of the center-of-mass and the internal transition in a trapped ion, driven by a classical laser beam, is discussed. Without using Lamb-Dicke limit, the precise analytical solution of wave function is deduced in this model. The numerical simulations show that, under proper parameters chosen, the apparent squeezing occurs in both the vibration and the spin variables for the trapped ion.

In order to investigate the damage of transverse stimulated Raman scattering (TSRS) to frequency-conversion crystals of high-power laser driver for inertial confinement fusion (ICF), the simulation and calculation of TSRS has been carried out. It is proved that when it works routinely, TSRS doesn′t damage the crystals if the ideal 3ω field is not modulated over time and space.

The light propagations in human lung and three-layer artery are simulated by Monte Carlo method. It results that, with the increasing of the refractive index, the diffuse reflectance R_d is linearly decreased and absorptance A is almost linearly increased. But for multi-layer tissues, the influence of the refractive index in the deeper layer of the tissue on R_d is less, and the influence of the refractive index in the different layer of the tissue on A is different because each layer has its own thickness and optical property. Therefore, the refractive index is a very important parameter in bio-tissue.

In this paper, the beam quality and polarization degree of laser beam which propagated in large core multimode power fibers is studied. Domestic fused silica optical fiber with core diameter of 0.6 mm and 3M silica fibers with core diameters of 0.4 mm and 0.6 mm were used for experiment. It is found that, the output beam quality factor M 2 is a compound tanh function of fiber lengths of every kind fiber. Linearly polarized laser beam launched into a multimode fiber suffer depolarization, the output beam′s polarization degree is an exponent function of fiber length and this relationship is agreed well with every kind of fiber.

In this paper, the transmitting characteristic of multimode fiber is improved by introducing the periodic scramble during the fiber′s drawing process. The scramble is some periodic and continuous left- or right-turning, so-called handness structure, by turning the fibers relative to the preform during the course of drawing process. The differential mode delay (DMD) test shows that this scrambling can reduce the split of optical pulse and improve the transmitting characteristic of multimode fiber.

The output energy distribution of modes in straight and bend hollow waveguide with GeO_2 dielectric layer and its deviation are discussed in this paper by experimental way. The reason why the output energy distribution of modes in dielectric hollow waveguide is better than normal hollow waveguide is discussed too.

The method of image scanning and encoding for each row is studied, and the new data structure for storing the image information is proposed. Compared with the conventional image logical algorithm, the region logical algorithm is studied. The region encoding and region logical algorithm have been used for object detection, and the results are given.

By means of dilution developing process for the silver halide holographic plate, the influences of exposure energy on refractive index and index modulation in emulsion were experimentally researched. According to the exposure characteristics of optical density and diffraction efficiency, the absorption modulation of silver-halide emulsion with dilution developing process will be ignored. The hologram is a volume phase grating with an average absorption coefficient but no absorption modulation. The index modulation mechanism of the gratings was discussed, and the characteristics curves of refractive index and index modulation of effective medium in silver-halide emulsion were revealed. The maximum of index modulation of silver halide emulsion can be reached at equally intensity between reference and object waves. The test results in carlier papers have been made clear.

With the introduction of overlapping factor, a new simulation model for fiber Raman amplifiers (FRA) is proposed. Using this new model in FRA simulation leads to obvious reduction of iteraction time with satisfactory accuracy. The effect of dispersion and nonlinearity on super Gaussian pulse pumped Raman amplifiers has been studied by solving the new model. The simulating results show that dispersion has great impact on the performance of fiber Raman amplifiers, while nonlinearity make little influence on in.

This paper studied the time shift caused by soliton collision in wavelength division multiplexed (WDM) weakly dispersion-managed system and the evolution of time shift, chirp, time position and frequency of soliton in WDM strongly dispersion-managed system. It shows that time shift leaded by solition collision is very low in weakly and strongly dispersion-management system, when the path-average dispersion approaches zero.

In this paper, the influences of the injection current and the position offset of SOA on the switching window of TOAD are studied by proceeding simulation and experiment. The increase of the injection current can increase the gain of SOA and the height of switching window. The width of switching window is determined by the position offset of SOA. In the experiment, continuous light was used to replace the signal pulses. With the increase of the position offset of SOA, at first the width of the main switching window increase, then decreases when it equals to half of the control pulse period.

The high energy pulse laser was used to radiate lead zirconate titanate (PZT) piezoelectric films. The effect of the laser thermal shock on the properties of the films was investigated. It was found that when the laser energy density was lower than the damage threshold of the films, the ferroelectric properties of PZT thin films changed after laser thermal shock. The remnant polarization value decreased from 32 699 μC/cm 2 to 26 316 μC/cm 2, the coercive field was basically constant at 38 396 kV/cm, and the fatigue property of the films became more stabilized, the Pr degradation ratio is from 44.3% to 34.7% at the cycles of 1.75×109 when the laser energy density was from zero to 19.89 J/cm2. Moreover, the micro-mechanism was discussed based on the experimental phenomena.

When the outline injury measurement of revolving object surface is carried out utilizing laser Doppler effect, intensity and quality of Doppler signals of the diffused light are essential parameters affecting measurement and its accuracy. In this paper, the laser Doppler reference optical system, average effect of diffused light phase random change of revolving object surface and least square fit method are studied, and a reference optical system with high signal noise ratio is designed, besides the loss signals arising from subtle structure of object surface are restructured, outline injury measurement of revolving object surface is attained with the relative error of 0.3%.

In real-time holographic interferometry, the phase measurement of the time-sequence interference fringes is very important. On the theoretic analysis, this paper proposes a novel phase measurement method by use of the phase variation of the object light wave and the phase-shifting technique, and obtains the calculational formula of phase variation in whole process.

Inverse problem is always encountered in particle sizing techniques based on the light or acoustic scattering. Here, through numerical simulation and experimental validation, the Twomey algorithm applied in the foregoing measuring methods was improved and the reasonable results of particle size distribution were got. As a result, the Philip-Twomey-NNLS algorithm combined with generalized cross validation (GCV) technique is proved effective to handle the inverse problem in particle sizing.

It is reported in this paper that femtosecond laser induced phosphorescence in Mn 2+ doped alumino-phosphofluoride glass and a new phenomenon of 365 nm UV light stimulated phosphorescence in femtosecond laser irradiated alumino-phosphofluoride glass after the femtosecond laser induced phosphorescence decayed completely. Possible mechanisms of these two types of phosphorescence are discussed. These phenomenons have potential uses in three-dimensional ultra-high-density optical recording.

Absorption and emission properties of Yb 3+-doped fluoroaluminate glasses were analyzed according to the measured absorption and emission spectra. The emission cross section of Yb 3+ ions was calculated. The fluorescence reabsorption effect and concentration quenching effect of Yb 3+ ions were discussed. Difference between measured emission section and calculated emission section of Yb 3+ was caused by the reabsorption effect, which also decreased the fluorescence intensity of Yb 3+ ions. The energy transfer from Yb3+ ions to Er3+ ions was the second key factor leading to concentration quenching in heavily Yb3+-doped fluoroaluminate glass.

The critical laser power density to induce plasma for different powders is studied in this article by means of fully-automatic laser welding machine LSM240. The powder components are FFe+15%TFe, FCo and FNi+15%TNi. The results show that the critical laser power density (I_C) to create plasma under the radiation of CO_2 laser beam for the three kinds of PM materials is I_ CFe>I_ CCo>I_ CNi, and the low critical gas flux Q_S is QFeS<QCoS<QNiS when the plasma has been efficiently controlled.

Single-walled carbon nanotubes (SWNTs) were prepared by continuous CO_2 laser ablation at room temperature. Transmission electron microscope (TEM) and Raman spectrum of SWNTs samples prepared by laser with power from 500 W to 850 W were measured. It gave the dependence of growth condition and tube diameter on laser power, and confirmed that laser power play a crucial role in SWNTs formation and tube diameter distribution in the preparation method of long wavelength laser ablation. The yield of SWNTs increas with increasing CO2 laser power. On the other hand, the higher the laser power, the larger the tube diameter of SWNTs in experiments.

3D laser cutting has been widely used in automobile and aerospace industry. In 3D laser cutting it is inevitable for laser head to move up and down, keeping the laser head vertical to the surface of workpiece. The orientation of laser head influences cutting result. In order to quantitatively analyse the relationship between cutting result and cutting parameters, the 10 marks quality-evaluation system of cutting result and ANN(artificial neural network) have been setup. The new knowledge can be introduced by ANN. These new knowledges have been used to guide actual cutting to realize intelligent laser processing.

In order to illustrate mechanism of the immune modulation effect of He-Ne laser irradiation with the concentration changes of splenic T lymphocytes induced IL-2 activity in mice, the effects of He-Ne laser irradiation on splenic T lymphocytes induced IL-2 activity in mice were studied. By irradiating upon the inner corners of the mice eyes with He-Ne laser at five different dosages of 7 33, 11 00, 14 67, 22 00 and 36 67 J/cm 2 for eight days,the splenic T lymphocytes induced IL-2 activity was monitored...

Using He-Ne laser to irradiate macrophages, the _i distribution of the single macrophage and the immunocompetence are studied in real-time by change laser power and irradiated time. Experimental result indicated that the _i of the macrophages increases with time and reaches the max value then decreases to preliminary station gradually, presenting cricoid-scalar distribution, the best strong in center and decrease radially. Different laser doses have different impact to macrophages _i and immunocompetence. With same laser wavelength and dose but different laser power, the change of [Ca2+]i and immunocompetence are also different obviously. When laser power is 0.16 mW, the max value of [Ca2+]i is almost six folds higher than that of the laser power is 0.40 mW. The max value of [Ca2+]i corresponding the station of the best strong immunocompetence. The action mechanism is primary discussed in this papaer.