This paper studies the effects of lens-like effect of the free-vortex aerodynamic window (FADW) of high energy lasers. First the properties of inevitable lens-like effect of FADW are studied experimentally. And then it gives the detailed description using the principle of matrix optics theoretically. At last the limit conditions of the FADW design originated from lens-like effect are discussed and analyzed.

In this paper, the thermal properties of a super-thin multilayer metal mirror with silicon substrate subjected to irradiation of high power lasers are experimentally demonstrated and theoretically analyzed. The structural designs for the mirror and the relations between thermal deformation and laser irradiating time are presented. The results show that under the condition that absorption laser power is 120 W, and laser irradiating time 4 s, the thermal deformation of the silicon super-thin multilayer mirror is 0.25 μm, but that of the general silicon mirror 0.71 μm. Theoretical calculations are relatively accordant with the experimental results.

In this paper, experimental study of two kinds of typical excimer lasers (XeCl: 308 nm, 30 ns and ArF: 193 nm,17 ns) etching PC, PI, and PMMA is described. The mechanism of excimer laser etching polymer is mainly discussed, and the performances of the two kinds of excimer lasers etching the polymers are compared.

In this paper, the conventional formula, used to design diffractive optical element (DOE) for beam smoothing, is modified. By using the hybrid algorithm merging hill-climbing with simulated annealing, the precise design of the DOE for beam smoothing is completed. Besides the used sampling points in the optimization, the intensity distribution of any uncontrolled points and with any sampling interval on the focal plane is consistent with the demand for beam smoothing.

Optical limiting properties based on reverse saturable absorption and thermal defocusing effect of organically modified sol-gel doped with octa-PdPc were studied. By utilizing this material, one optical limiter for indoor protection against visible pulse and continuous wave lasers was designed. The limiting effect of the limiter can be further enhanced by means of adjusting the size of the aperture or increase of the limiting medium layers. For the light with the wavelength of 488 nm, the transmittance of the limiter is less than 9% when aperture size is 2.2 cm. For lights of 632.8 nm, 514.5 nm and 457.9 nm, they have the similar limiting behaviors as the light of 488 nm.

Because of special beam intensity distribution of Shenguang Ⅱ laser facility, the equable-width-element cylindrical lens array line-focus system cannot lead to satisfying line-focus. It′s essential to calculate the effect of beam distribution. In this article, optimized design and manufacture of inequable-width-element cylindrical lens array line-focus system were done. It can make very good uniform line-focus with relevant experimental scheme. Good results of X-ray laser experiment proved the resultful design.

A neon metastable beam source was built up, from which Neon metastable beam of the intensity of 3.3×10 14 atoms/s·Sr. was generated. The characteristics of the metastable Neon beam were studied, and the corresponding mechanisms are discussed.

This paper reveals a novel magneto-optic recording characteristic of Indium Bismuth Calcium Vitriol Iron Garnet (In-BiCaVIG) crystals in high power microwave (HPM) field. The initial state of magneto-optic rotation in the In-BiCaVIG crystal changes under about 100 MW HPM pulse, 2～10 GHz in frequency and about 50 ns in width. The changing values of magneto-optic rotation are related to the peak intensities of magnetic field in the direction of optical path. The changed directions of magneto-optic rotation are related to the initial states of crystals. The changing magneto-optic rotations related to the HPM magnetic field can maintain in the crystal for several days or more unless being erased by a magnetostatic field.

The broad bean (Vicia faba L.) seeds were irradiated by He-Ne laser and CO 2 laser, then both of MDA and AsA were tested in the stage of their seedlings. The results showed that He-Ne laser was better that CO 2 laser. The best dose of He-Ne laser was 5.43 mW·mm -2 . He-Ne laser pretreated seeds and 3.03 kJ·m -2 UV-B irradiated seedlings in the condition of PAR 70 μmol·m -2 ·s -1 . SOD, POD, CAT enzyme activity, SOD, POD, CAT isoenzymes were measured. The results showed that He-Ne laser could enhance SOD, POD, CAT enzyme activity, changed SOD, CAT isoenzyme bands. It was concluded that laser pretreatment could protect broad bean seedling from UV-B irradiation damage.

By controlling the transmitted resonant wavelength of a Fabry-Perot filter, stable single frequency laser output which corresponding to one of the reflected wavelength of a five fiber Bragg grating wavelength division multiplexing (WDM) array acted as selective reflector was obtained and with slope efficiency of ～0.09. Experiment demonstrated that the lasing threshold is related to the grating′s reflectivity and the gain of the erbium-doped fiber at the working wavelength. Continuous tuning within the range of 1530 nm to 1575 nm was achieved with the grating array replaced by a board band reflective mirror.

The growth of Al-free active-region high power SCH-SQW laser by LP-MOVPE is reported. CW output power is up to 1 W with W=100 μm wide stripe and L=1 mm long cavity length. The lasing wavelength is λ=849 nm and the threshold current density is J th =460 A/cm 2.

A new type of preionization-PCB (printed circuit board) preionization is studied. As a distributing capacitor′s coupling apparatus, PCB preionizer is placed on both sides of the main discharge electrodes and creates quite uniform preionization. Output characteristics of a mini TEA CO 2 laser using PCB preionization are measured at different pressures of the laser media.

A widely tunable quasi-phase-matched optical parametric oscillator that uses periodically poled LiNbO 3 with a multigrating structure is reported in this paper. With a 1064 nm acousto-optically Q-switched Nd∶YVO 4 pump laser, a tunable IR output from 1.436 μm to 1.7 μm is obtained. The threshold is 10.3 μJ with pulses repetition rate 10 kHz. The maximum output energy of signal is 4.25 μJ with the conversion efficience of 12.5%.

The performance of the intracavity KTP OPO output beam divergence as a function of resonator parameters have been investigated experimentally. The Cassegrainian unstable resonator has been demonstrated to be one of efficient means to decrease the OPO beam divergence.

In the hypothesis of plasma isothermal expanding, enhanced effect of radiation coupling induced by laser-generated plasma on aluminum target is studied analytically. The calculation results have demonstrated the significance of plasma re-radiation in interaction of powerful pulsed laser with metal target. These results agreed with experimental data well, and explained the experimental results theoretically.

Physical, spectral and laser properties of ytterbium borate and phosphate laser glasses were researched. Assessing from thermal mechanical property, nonlinear property, glass transition temperature and spectroscopic properties of both glasses, it is found that as a laser medium ytterbium phosphate glass is a better candidate than ytterbium borate glass. Pumped by a 6 W, 974 nm laser diode, tunable cw laser with 62 mW maximum output power and 4.4% slope efficiency was achieved in the ytterbium phosphate glass. In ytterbium borate glass, pumped by 1 W, 940 nm Ti∶sapphire laser 8 mW quasi-cw laser output of 8 mW was obtained. The laser performance of ytterbium phosphate glass is confirmed to be better than that of ytterbium borate glass.

A method for determining the positions of laser beam has been introduced, in which a photodiode array combined with a CMOS signal processing circuit chip is used as a detector to measure the beam position with a large measurement range. Moreover, an interpolation method is used to improve the resolution of the photodiode array. With successfully measuring the beam shifts for the two kinds of laser alignment system, it is confirmed that the photodiode array and the interpolation method are available in laser alignment for long distance.

Using the all-fiber interferometer, a novel method of optic fiber length measurement is proposed in this paper and the all fiber interferometer for fiber length measurement is constructed. Through the experiment, the principle of the system is proved properly and the system's measuring purpose is realizes.

An experiment of measuring thermal diffusivity of material by laser pyoelectric effect is reported. The phase of pyoelectric signal is detected by photothermal pyoelectric technique, then the thermal diffusivity of material is determined by nonlinear fitting. The detection system is designed. Single-arrange composite Al 2O 3/Al is measured, and thermal diffusivity at arbitrary direction was measured by this method.

Aiming at power balance control in "Shenguang Ⅱ", a means for precise attenuation measurement of angular variable mirror (AVM) used in main amplifiers are proposed, and a set of measurement equipment controlled by computer is established. Using this equipment, a limiting relative error 0.5% of measurement precision is achieved.

Two photon pumped frequency upconversion and the two-photon absorption (TPA) induced nonlinear absorption of a dye, trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulfonate (abbreviated as HMASPS) have been experimentally investigated. The dye exhibits strong superradiation properties when the pumping power is above its threshold. Furthermore, the lasing upconversion efficiencies from 900 to 1150 nm and the nonlinear absorption from 720 nm to 1100 nm have been measured. The largest effective molecular TPA cross section was measured to be 44.3×10 -48 cm 4s/photon at 920 nm. At 1064nm, it was 2.77×10 -48 cm 4s/photon. The highest upconversion efficiency is 7% at 990 nm, whereas 4.3% at 1064 nm.

A novel π-conjugated polypyrrole derivative-poly{(pyrrole-2,5-diyl)[p-nitrobenylidene]} (PPNB) is synthesized. Its solution in N-Methyl-2-pyrrolidone (NMP) and its thin film combined with polyvinyl alcohol (PVA) are respectively prepared. With 532 nm, 8 ns laser pulse as pumping beam and He-Ne laser beam (632.8 nm, CW) as probing light, the nonlinear optical response times of the PPNB solution and film are measured. The building-up times of the laser induced refractive index change of the PPNB/NMP solution and the PPNB/PVA film are measured to be 4 μs and 5 μs, respectively. Their recovering times are 30 ms and 5 ms, respectively. This optical nonlinear phenomenon may be mainly dominated by the thermo-optical nonlinear effect.

In this paper, the influences of multi-perturbations originating from amplifier spontaneous-emission (ASE) noise and cross-phase modulation (XPM) in wavelength-division-multiplexed (WDM) are simultaneously considered by using the variational method to analyze evolvement characteristics of dispersion-managed soliton transmission. Simple analytical expressions for dynamics equations of dispersion-managed soliton and timing jitter are obtained. At last, the degrees of effect to system for three perturbations are given.

Relationship between boron-doped content and single polarization single mode band-width of W-tunneling optical fiber is analysed. The band-width is independent on the boron-doped content and is determined only by the profile structure and refractive index depth of the inner cladding when the fiber is long enough. For short W-tunneling optical fiber, increasing of boron doped content can raise leakage losses of the fundamental modes below cut-off. It can enhance extinction ratio and effective band-width of the fiber to some extent.

A low crosstalk structure is proposed and analyzed for the integrative optical add and drop multiplexer/optical cross-connect node (OADM/OXC) that implements the function of the OADM and the OXC simultaneously in wavelength division multiplexing (WDM) optical transport networks. For joined adding and dropping, a set of 1×2 and 2×1 switches are placed before the cross-connect switches instead of using larger dimensional cross-connect array. Simulation result shows that the power penalty can be decreased significantly in the proposed structure.