In this paper, theoretical formulae were developed to calculate the second order sensitivities of strain and temperature. Numerical results were given to show how the second order sensitivities introduce the errors between the solutions to the set of linear equations and the set of nonlinear equations including the second order terms.

A large aperture phase shifting infrared interferometer is developed, which uses a CO2 laser source (λ=10.6 μm) comprising of a Fizeau interferometer with the aperture reaching φ250 mm and an accuracy better than λ/100. And a Twyman spherical interferometer, using a piezoelectric transducer (PZT) to shift a reference mirror and pyroelectric vidican (PEV) as the detector, can also be formed. While phase measurement interferometry (PMI)is carried out, the temperature modulation of the PEV target is also being down. A series of software packages used to fit the wavefront and evaluate image quality are incroporated into the instrument. The testing results of IR telescope wavefront and the flatness of glass mastering discs are presented.

The preliminary result of the frequency stabilization of an InGaAsP semiconductor laser using the optogalvanic effect of a gas absorption cell is reported. The optogalvanic signal of the discharge absorption cell is used as a frequency standard.

The spectrum and polarization sensitivity of etched optical fiber Bragg reflectors are studied experimentally and theoretically. Their polarization sensitivity results from the destruction of the round symmetry of the fiber cross section, and the distinct peaks observed in the reflection spectrum result from multiple modes supported by the waveguide. The cut off condition of the high order modes is presented. The polarization sensitivity and bandwidth of the reflectors can be reduced by optimizing their construction parameters.

A coupling technique between a cone endface fiber and LD with the advantage of high efficiency and low reflectance is presented. The coupling efficiency nearly 90% and the reflectance loss approximately 60 dB are calculated using mode coupling theory. Experimentally, the best coupling efficiency measured is 73.9% and the reflectivity is less than -50 dB. In addition, a new equipment for fabricating the conical microlens is designed, which has the advantages of low cost, simple manipulation, and high finished-product-rate.

The eigenmode of a hollow waveguide with two curved surfaces was analyzed with Helmholtz equation and the transmitting efficiency of the hollow waveguide was analyzed with a ray optics approach. The hollow waveguide was fabricated and the experiment of laser propagation in it was carried out. Finally, the CO 2 laser power of 1040 W was delivered through the waveguide.

The resonant absorption effects and chaotic characters of the laser DNA molecule interaction are studied by quantum mechanics and nonlinear theory. The results may explain the effect of genetic mutagenesis of laser.

A kind of phase computer generated grating with non equal distance spot arrays was designed and fabricated according to the needs of the window distribution of the FET SEED smart pixel device in optical switching network. A semiconductor laser diode with wavelength of 0.85 μm was used as the pumping light source. The number of spot arrays is 16×16 with the ratio of the spot distances being 1:4. The ratio of the constrained spot light indensity to the required one was less than 3%.

An all optical demultiplexing experiment using a semiconductor laser amplifier in a loop mirror from 4×2.5 GHz optical time division multiplexing is reported. The results show that demultiplexed signals with good extinction ratio can be achieved.

A novel phase unwrapping algorithm, based on intensity modulation analysis and adaptive threshold is presented. It is successfuly used to unwrap phase maps in Fourier transform profilometry.

Using OM, SEM and X ray diffraction analyses, the investigation into microstructure and hardness profiles of a WC 18% Co hardmetal after laser processing has been conducted. The microstructure can be divided into Co phase, β, remelted zone, WC grains resolved precipitated zone and substrate. By virtue of these changes the highest hardness is 1544 Hv and the increment can be 34～37% compared with the original hardness of the material. From the X-ray diffraction results it follows that the content of face centered cubic cobalt will be varied and the hexagonal close packed cobalt may occur or increase, but their constituent proportions are connected with the laser processing parameters.

The calculated results of the gain, threshold current density and its temperature dependence of InGaN QW lasers based on the available parameters are presented in this paper. The threshold current density of nitride blue and green QW lasers is more than five times higher than that of GaAs QW lasers, but their characteristic temperature can be raised up to 500 K.

A high quality single crystal of Cr4+:YAG, grown in our laboratory by the Czochralski method was used in the Q-switching experiment successfully for a Nd:YAG laser, which provided laser pulses of 800 ns in duration, a repetition rate of 3～13.33 kHz and an average pulsed output power higher than 13 W. The jitter of the Q-switched laser is also discussed in this paper. A possible mechanism was suggested and indicated that a more stable output of Cr4+ :YAG Q-switched laser would be achieved by further improving the crystal qulity in the growth and post-treatment processes.

In this paper, the properties of a flashlamp pumped Cr:LiSAF laser operating in Q-switched modes are reported. The stable Q-switched pulse with energy of 85 mJ and pulse duration of 50 ns (FWHM) is obtained. Wavelength tuning is realized from 810 to 890 nm continuously by a two plate crystal quartz birefringent filter (BRF). The properties of Q-switching versus crystal high voltage and tuning element are also given.

In this paper, the study of spectral properties of a Tm:YAG crystal and the analysis of the advantages of suitable LD pumping in Tm:YAG crystal were reported. The effects of OH -1 in Tm:YAG on laser properties were also analysed.

A novel H shaped vertical cavity surface emitting laser is reported in this paper. The structure is obtained by H + implant using tungsten wires as the mask and the lift off etching technique. The current is conducted through regions between notchs and windows, then funneled into the GaAs active layer. In a preliminary experiment, at room temperature 0.1 duty cycle 20 μs width pulses operation has been realized.

A modified liquid phase epitaxy method was used to grow InGaAsP materials on the GaAs substrate. The FWHM of photoluminescence at 10 K was 14 meV, wafers of SCH multilayer epitaxial structures were obtained with a threshold current density of 300 A/cm 2, and the hgihest CW output power obtained from wide stripe lasers was 2.1 W.

In this paper, reported is influence of the electrical poling conditions on the electroinduced second order nonlinearity in fused silica. It is found that the second harmonic generation in fused silica caused by electrical poling at elevated temperature is dependent upon the electrical poling temperature and voltage. By poling glasses with a certain voltage, the SHG intensity acquires a maximum value at a moderate temperature, while the SHG intensity increases with the rise of poling voltage and reaches the saturation gradually when the poling temperature is fixed. The experimental results can be explained reasonably by the dipole orientation model for the electroinduced second order nonlinear polarization in glasses.

This paper describes the experimental investigation of stimulated Raman scattering and stimulated four photon mixing obtained from an Er doped silica fiber. Six orders of stimulated Stokes scattering in the range of 552.1～622.8 nm and the Stokes (λ=542.9 nm) and anti Stokes (λ=537 nm) of stimulated four photon mixing have been obtained from a 10 m Er doped single mode silica fiber, which was pumped by a frequency doubled Q-switched Nd:YAP laser (λ=539.7 nm) with a pulse duration of 50 ns. Its output energy is 0.1 J.

This paper reports researches on the property of laser traveling in a thick medium and photoionization of laser atom interaction. The equation of three step photoionization for describing the field and the density matrix as well as the atomic population was derived. The ionization probability evolution with laser parameters is calculated in different cases. It was found that the laser transfer in a long distance causes evolution of laser parameters. Laser power, laser pulse shape, pulse width and time stepout of three laser bunches are the main factors of affecting the photoinization probability.