A novel reflective bridge shaped compensation configuration has been developed for the polarization modulated fiber optic temperature sensors. We study the practical compensation effects of this configuration by designing the corresponding experiments. It is proved that this system can improve the measuring accuracy and long term stability.

In a collimating system formed by a pair of quarter pitch gradient index rod (GRIN) lenses, there exist three kinds of assembling misalignments: lateral offset, longitudinal separation and angular tilting. Excess coupling losses so arise. The losses increase quadratically with the misalignment amounts when they are small, depending on the focusing parameter of the GRIN lens. It is possible to reduce the excess losses greatly by choosing an appropriate lens in accordance with the practical assembling conditions.

The phase shifter is a key element in phase shifting interference metrology. Its calibration is an important process that cannot be neglected. The accuracy of calibration has a great influence on the measuring precision. It determines the success or failure of a phase shifting technique. A calibration method of a phase shifter is presented in this paper. It owns the features of high precision and has no special requirement for the linearity of the phase shifter. The calibration is performed with the same optical set up as it is actually used. The errors owing to the different optical paths for calibration and for actual use are thus deleted.

Installing two pairs of electrodes in an optical resonant cavity, while keeping the of operating voltage and the volume of the discharge zone indentical, we found that when the time interval of the pulse discharges of the two pairs of electrodes is τ =0 s, an effect of pulse energy enhancement occurs, the output energy increases by about 30% Theoretical result obtained is in accord with that of the experiment.

A novel wavelength scanning fiber optic interferometer for absolute distance measurement has been proposed. Based on the digital signal processing techniques, an algorithm to effectively discriminate phase information, eliminate perturbations and overcome the random drifts of the scanning wavelength, is established. So, the practical demands of a precision 0.05 μm and a resolution 0.01 μm are met.

A new alignment technology was proposed here. Substrates coated with polyvinyl alcohol (PVA) and methyl orange (MO) layer were illuminated by a linearly polarized laser for certain time. Subsequently, a liquid crystal (LC) cell was assembled with the polarized direction of the illuminating light of both substrates mutually perpendicular, from which a twist nematic (TN) alignment of LC molecules has been got. When a beam of linearly polarized light transmits through the LC cell, the polarization direction will rotate 90°. After the laser illumination, the twist nematic structure of the LC cell keeps unchanged after a number of shots of high power laser pulses.

A method for estimating the signal noise ratio (SNR) of digital images retrieved from volume holographic memories stored in Fe∶LiNbO 3 crystals is proposed in this paper, which is applicable to the image detection array (CCD) of entertainment quality. Based on this method the dynamic development of the image SNR during recording is measured for the first time to our knowledge. The degradation of SNR due to both intrapage and interpage cross talk noises is quantitatively studied in detail. The experimental results show the same descending trend on SNR as the result from a theoretical analysis. The degradation of the SNR is mainly caused by the optical noises in optical systems and the electrical noises in the measuring instrument. The experimental results also show that images can be retrieved with satisfactory SNR even the diffraction efficiency is very low. Therefore, an optimal compromise between the storage capacity and the retrieved image quality is possible.

Fractional Fourier transform is applied to produced hologram. For different recording methods, we study the conjugate relation and the magnification relation of the non lens reappear image of the fracional Fourier transform hologram. The mathematical expression and the physical interpretation in the condition of the paraxial geometrical optics are given. Its reliability and feasibility are demonstrated by computer simulation.

In this paper, an extensive complementary encoding method is presented for realizing morphological hit or miss transformation by only one step. An opto electronic hybrid target recognition processor is developed. An incoherent correlator is used as its optical implementation hardware and a liquid crystal display panel is used as its real time spatial light modulator. Experimental results have shown that the recognition accuracy is over 90%, and human face images with 40% noise, 50% loss, 6° rotation and even different facial expressions can also be recognized.

From the theory of phase transformation and thermal elastoplastic, and based on experimental data of laser quenching, a non linear coupling heat conduction equation considering phase transformation, temperature field and variable physical properties can be estabilished. A model of the relationship between the phase transformation producers and the material properties is put forward which is resolved by means of the Finite Element Method (F.E.M.). Comparing the calculated results with those of experiments, satisfying agreement is found. It might be valuable for some practical applications and for the development of theory.

A 24 mW He Ne laser irradiation was applied to the spleen region to observe the changes in levels of the tumour necrosis factor (TNF) and TNF receptor (TNFR) in mice with tumour. The results showed that TNF and TNFR were significantly higher in both of laser groups than control groups. It indicated that He Ne laser not only enhances the level of TNF but also promotes the expression of TNFR.

The light output of a LD is effectively collected, pre collimated with a cylindrical lens, and coupled into a multi-mode fibre. The emitting width and lasing wavelength of the LD is 150 μm and 808 nm, the coupling efficiency between the LD and a 200 μm core diameter fibre with flat end is greater than 90%, and more than 1.0 W CW output from the fibre has been achieved. Also, main factors affecting the coupling efficiency are analysed.

Without an additional fluorine donor, the Kr/Ne mixture was excited in an excimer laser with teflon surface preionization plates. The relative UV spectrum was analyzed by ways of spectrography and opto electric scanning. The formation of KrF excimer was affirmed. The relations of emission spectrum with parameters were studied.

Making use of the optical phase conjugation effect and the pulse compression effect in stimulated Brillouin scattering (SBS), we present a Nd∶YAG laser with an induced phase conjugate resonator, of which the output is 250 mJ, the pulse width is shorter than 5 ns. The measurement results are given.

Using the transmission characteristic of the Gaussian beam after a lens and the thermal stability in a broad range of the special telescopic resonator, an adaptive compensatory system for thermal lens focus is designed to weaken the effect of the thermal lens in light pumped solid lasers. Thus, a stable output radius can be achieved while the thermal lens focus varies in a broad range.

The properties of a domestic flashlamp pumped Cr∶LiSAF laser are described. An output energy of 992 mJ and slope efficiency of 1.5% are obtained.

Based upon the laser rate equations including relaxation between energy levels, the optimum model of a multipass amplifier is constructed. By computer simulation, an optimum input fluence distribution is obtained and the performance of the laser amplifier under such optimum is discussed.

Multiply charged Co and Ti ions have been produced by means of laser ablation from metal oxides targets in a RF ion trap. With cooling collision of two separated crossed ion beams at right angles and the selective trapping, the low energy (electron volt) Co 3+ and Ti 4+ ions were successfully produced and stably stored in the trap.

Letting the beam doubly pass an acousto optic frequency shifting system and using the technique of saturated absorption spectra of cesium atoms we realized the frequency offset locking of a single longitudinal mode laser diode to the hyperfine transition of 6 2S 1/2 F=4→6 2P 3/2 F′=5 of cesium atoms. The characteristic is that the detuning can be changed conveniently by tuning the working frequency of the acousto optic frequency shifter without readjusting the optical system.

Low loss SiO2 TiO2 waveguides were fabricated with sol gel techniques. Propagation loss of 0.57 dB/cm was obtained at 633 nm. A Y branch channel beam splitter was also fabricated on a Si substrate. The branch ratio is approximately 1∶1.

By means of projecting a reference light and measuring the light on the photocathode of a streak camera, the minimum excited threshold in electron trapping materials can be measured. The infrared minimum excited threshold of CaS∶Eu, Sm is measured to be less than 4.8×10 -9 J/mm 2 by a visible streak camera. The minimum detectable energy density of the camera is less than 8.3×10 -10 J/mm 2 (532 nm). The phosphor investigated is efficiently stimulated with the 1.064 μm photons from a pulsed CPM Nd∶YAG laser. According to the result, it is shown that this kind of novel materials might be used in the ETM based infrared photocathodes and other fields.