The results of experimental and theoretical studies on creation of a super-long conductive canal technology for energy delivery from the space are presented. A high repetition rate pulse-periodic laser system and the most important components for the project realization are analyzed. The optical system and dust plasma based the conductive canal idea for long range energy delivery is discussed in details,then, some experimental approaches to dust plasma conductivity tests and new data of measurements are investigated. Finally,new applications of "Impulsator" program suggested are highlighted.

The ultrafast spectroscopy by a sub 5 fs pulse laser was applied to the simultaneous study of electronic relaxation and vibrational dynamics in RuⅡ(TPP)(CO). The signals due to 1Qx(1,0)(π,π*) and 1Qx(0,0)(π,π*) are thought to decay in a sequential order from the higher energy states to the lower energy states in the sequences 1Qx(1,0)(π,π*)→1Qx(0,0)(π,π*)→3(d,π*)→3(π,π*) and 1Qx(0,0)(π,π*)→3(d,π*)→3(π,π*). The electronic lifetimes of 1Qx(1,0)(π,π*),1Qx(0,0)(π,π*),3(d,π*), and 3(π,π*) are determined to be (230±70) fs, (1150±260) fs, (2150±360) fs and larger than 4.8 ps, respectively. The lifetimes of 3(d,π*), and 3(π,π*) are estimated to be (2 150 ± 360) fs and larger than 4.8 ps, respectively. The lifetime of 1Qx(1,0)(π,π*) determined to be (230 ± 70) fs, is in relatively good agreement with the step-down time of (190±40) fs for the transition time from 1Qx(1,0)(π,π*) to 1Qx(0,0)(π,π*) calculated from the energy decay rate in the dynamic Stokes-shift process. The spectrogram analysis shows that the time dependent changes in the vibrational spectrum is associated with the spin state change from the Franck-Condon state in the excited singlet state to the triplet state via the curve crossing point or conical intersection between the singlet and triplet potential surfaces. It is found that the dynamics is can not be expressed in terms of the simple single exponential decay of the spectrogram signal of singlet and exponential growth of the triplet vibration spectrogram signal. In stead, the vibrational spectral change takes place with more complex dynamics. At first, the decay of the singlet vibration spectrum takes place and then new vibrational spectrum which is different from singlet and triplet states appears. After the growth and decay of the new vibrational spectrum, the triplet state vibration spectrum starts to grow. The dynamics at first looks different from that of electronic spectra. The reason of the apparent difference can be explained in the following way. The vibrational spectral change could sensitively detect the structural difference among the singlet sate and triplet state in their equilibriums and that of transition state or state close to the conical intersection.

Generators with Inductive Energy Storage (GIES) are developed for laser applications. Discharge and laser parameters in high-pressure gas mixtures are studied. It is shown that the IES generator produces a high-voltage pre-pulse and the sharp increase of discharge current, which allows to form a long-lived stable discharge in different gas mixtures. Therewith the pre-pulse parameters can be easily controlled and optimized for each gas mixture. Without the IES breakdown voltage and amplitude of the first discharge,the current spike decreases by a factor of 1.5-2 and results in pure laser parameters.The maximal radiation power, output energy and the laser pulse duration of a N2 laser are obtained. The UV output is as high as 50 mJ in 40 ns pulse duration (FWHM), while that on the IR transition exceeds 25 mJ. The cascade lasing on N2 molecule transitions is achieved. As a result,the total pulse duration on the C3Пu-B3Пg band is extended up to 100 ns. The improvement of both pulse duration and output energy are achieved for XeCl, XeF and KrF excimer lasers. The maximal efficiency of XeF laser is as high as 1.6%, while peak output is 0.85 J and maximal pulse duration exceeds 200 ns. Up to 650 mJ in a 160 ns pulse is obtained at 248 nm by the discharge KrF laser with the efficiency of 3.3%.Finally, HF(DF) non-chain lasers with ultimate efficiency of 7.7-10% are developed,and the efficient operation on CO2 molecules with high peak power is demonstrated. The laser output at 10 600 nm is 6.2 J with the efficiency up to 25%.

The laser surface modifications of a bulk material Inconel 600 and a multilayered titanium-aluminium-nitride/titanium-nitride(TiAlN/TiN) coating are of great interest for fundamental and practical aspects. Observation of surface changes of the Inconel 600 and TiAlN/TiN induced by ultra-short (fs and ps) and short (ns) lasers is considered. It is shown that all laser systems can stimulate morphological changes at the target surface,and the irradiation with ultra-short pulses results in a better definition of the damage. Fs laser pulses can produce a sharper destruction in comparison to the ps pulses and it gives the conical cross section of the crater, which is in contrast to the semispherical shapes ps laser beams. Furthermore, thermal effects are dominant in the case of ns pulse,and all irradiations are accompanied by the plasma.

Nonlinear optical (NLO) properties of the colloidal solutions of chemically synthesized undoped and Mn2+ doped ZnS Quantum Dots (QDs) in methanol are measured by using a Q-switched 10 ns pulsed Nd∶YAG laser radiation by the Z-scan technique. The nanostructures of the synthesized materials are characterized by using different characterization tools, such as Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) analysis. Linear optical absorption and Photoluminescence (PL) emission characteristics of the colloidal solutions of the synthesized QDs are measured at room temperature by using a UV-visible spectrophotometer and a spectrofluorimeter, respectively. The absorption characteristics of the samples show that the absorption cut-off of the samples is below that of the bulk ZnS due to the quantum confinement effect. Photoluminescence emission characteristics measured at room temperature show that the Mn2+ doped ZnS sample exhibits its visible PL emission peak at ~580 nm, whereas the undoped ZnS sample emits in the ultraviolet region peak at ~365 nm. The average particle size (radius) of the as-prepared ZnS sample is ~1.2 nm as determined from the measured UV-visible absorption characteristics as well as from TEM and XRD data analyses. By analyzing the experimental data obtained by the Open Aperture (OA) Z-scan technique, it is found that the Four-photon Absorption (FPA) takes place at 1064 nm wavelength in both the studied samples. FPA coefficients and FPA cross-section of both the samples are extracted by fitting the experimental data with the available analytical expression. It is found that the calculated value of FPA cross section of ZnS QD is 4.9×10-106 cm8·s3·photon-3, which is five orders of magnitude larger than that of bulk ZnS. Optical limiting property of the synthesized ZnS QD is also presented. The simultaneous presence of large FPA cross section and large luminescence efficiency in the visible region in Mn2+ doped sample would render this material as a good candidate for multiphoton fluorescence imaging applications.

The investigation results for the possibility of a pulsed inductive cylindrical discharge as a new method of pumping gas lasers operating at different transitions of atoms and molecules with different mechanisms of formation of inversion population are presented. The excitation systems of a pulsed inductive cylindrical discharge (pulsed inductively coupled plasma) in the gases are developed and experimentally investigated. At the first time, four kinds of pulsed inductive lasers on the different transitions of atoms and molecules are created. Characteristic features of the emission of pulsed inductive lasers are ring-shaped laser beam with low divergence and pulse-to-pulse instability is within 1%. Firstly, the red laser on the electronic transitions of atomic fluorine (FI) pumped by a pulsed inductive cylindrical discharge is developed. Lasing at 8 wavelengths in the spectral area 624-755 nm is obtained by exciting He-F2 (NF3,SF6) gas mixtures in a pressure range from 2.66-46.55 kPa. The energy of the FI laser is 2.6 mJ at pulse durations of 80 ns and the divergence is 0.4 mrad. Secondly,the far infrared laser on the vibrational-rotational transitions of CO2 molecules in the ground electronic state with a wavelength of 10.6 μm is created. The maximum energy of this inductive laser is 152 mJ at the pulse duration of 160 μs (FWHM). Thirdly, the pulsed inductive discharge H2 laser at the electronic transitions of hydrogen molecules in near IR laser is also developed. The laser action on four lines with 0.835 μm, 0.89 μm, 1.116 μm and 1.122 μm is obtained,and its pulsed peak power is 11 kW at duration of 20 ns.Furthermore, the pulsed inductive UV nitrogen laser on self-limited electronic transitions C3Πu→B3Πg at 337.1 nm and 357.7 nm is created,and its maximum generation energy is 4.5 mJ at low pressures 133 Pa and pulsed peak power is 300 kW at pulse duration (15±1) ns. The measured divergence of the inductive nitrogen laser radiation is 0.3 mrad.

A terawatt hybrid laser (THL-100) system on the basis of a starting complex and a final amplifier with gaseous optically driven active media on XeF(C-A) molecules is presented. The starting complex manufactured consists of a Ti: sapphire master oscillator pumped by femtosecond pulses from a continuous laser pumped by (Verdy-8) at a wavelength of 532 nm, a femtosecond pulse stretcher, regenerative and multipass amplifiers pumped by a pulsed laser at a wavelength of 532 nm, a diffraction grating compressor and a second harmonic generator (KDP). The complex has the following output parameters of the laser beam: pulse duration is 50 fs, the energy of radiation at the second harmonic (475 nm) is 5 mJ. The complex can operate in a single pulse mode and a frequency of 10 Hz. The XeF(C-A) amplifier consists of a two high-voltage pulsed generator (linear transformer), a vacuum diode with six cold explosive-emission cathodes, a electron beam injection system, a Xe filled gas chamber-converter and a laser cell. The high-voltage generator consists of 12 transformer stages,and each of them involves eight capacitors (one is C=40 nF) and spark gaps. The capacitors can be charged up to voltage of 100 kV. E-beam in vacuum diode has the parameters in total current of 300 kA, peak voltage of 550 kV, pulse duration of e-beam power about 150 ns (FWHM). The total energies of the six 100 cm ×12 cm e-beams which pass through the foil into the Xe converter are 6-7 kJ in the 150-160 ns pulse (FWHM). Pump energy cascade processes lead rapidly to the formation of Xe*2, which radiates a fraction of the deposited energy in the continuum at (172 ± 5) nm. This VUV radiation is transmitted through CaF2 windows into the laser cell containing the mixture of XeF2 vapour and N2 buffer gas. VUV radiation makes photolysis of XeF2 molecules form XeF* excimer molecules. The active medium of the amplifier pumped by VUV radiation has 24 cm aperture and 110 cm length. The results of numerical modeling of the output parameters and first experimental results are presented in this paper. According to the modeling of the XeF(C-A) amplifier parameters and the first measurement of gain, it is shown that the maxmum output energy is 2-3 J,which means that the peak power has been up to 40-60 TW in a 50 fs pulse.Furthermore, It is very important that this laser system can provide a high temporal contrast up to 109-1010.

The experimental and studied results of the structural, optical and nonlinear optical properties on the highly anisotropic especially un-doped and doped layered semiconductor GaSe (gallium selenide) and related crystals, InSe, GaS and GaSe-GaS (solid solutions) are overviewed. It includes also the investigation results on optical properties performed by confocal Raman and photoluminescence (PL) microscopy. Some experimental results on optical properties of GaSe nanoparticles obtained via ultrasonication and laser ablation methods are considered also.The properties of ε-GaSe is emphasized, which has one of the highest coefficient χ(2) of optical second-order nonlinearity and are crystallized into four different polytypes (ε,γ,β,δ), containing different number and arrangement of layers per unit cell. It is shown that GaSe may be considered as one of the best crystals for nonlinear applications in the IR range. More than 1 700 papers describe the physical properties of the GaAs and indicate that it is an outstanding material for applications to the teraherz (THz) spectral range. The domain structure of the crystal in connection with the Nonlinea Optical(NLO) properties is discussed by confocal Raman microscopy experiments. In spite most important physical properties of these materials are mainly investigated, further studies of optical absorption near the fundamental edge, PL, NLO properties in the IR and THz ranges as well as physical properties of their nanoparticles are necessary to understand the connection between the 2-D crystal structure and the physical properties. It is known that the nanoparticles of GaSe and GaSe- type crystals are highly interesting because they have a single tetra layer structure consisting of covalently bond –Se-Ga-Ga-Se- tetra layers. Some of GaSe-type crystals have band gaps in the range of 1.2-1.5 eV (InSe, GaTe) which make them and their nanoparticles suitable for photovoltaic applications.

The experimental results on study of characteristics of the high-pressure volume (diffuse) discharges in nitrogen at applying to the interelectrode gap voltage pulse with the amplitude of hundreds kV, duration of several ns and the rise-time of fraction ns are presented. At the pressure range of nitrogen in (0.2-4)×105 Pa, the discharge transformation from the diffuse form to the spark is investigated. Dependencies of the current amplitude and FWHM of the runaway electron beam current on nitrogen pressure are determined. It is shown that the generation of the Supershort Avalanche Electron Beam (SAEB) leading to the formation of diffuse discharge in the gap has a significant influence on the development of the discharge. At the pressures indicated above, the dependence of the time delay of SAEB’s moment generating relatively discharge current beginning on pressure are obtained. According to this dependence, the time delay changes as pressure increases and it is minimal at pressure of 2×105 Pa. Also, it is shown that the maximum peak value of diffuse discharge current pulse decreases with increasing pressure. At a pressure of 0.5×105 Pa with the use of blade electrodes and the N2∶SF6=10∶1 active medium of length 6 cm, the output laser energy of 2 mJ is achieved for the pulse power of 0.55 MW. It is reported that during the treatment of the AlBe foil by the Runaway Electron Preionized(REP) discharge in atmospheric pressure air, its surface layer is cleaned from carbon, and atoms of oxygen penetrate into the foil (by 450 nm per 300 pulses).

The research on laser combustion diagnostic techniques is reviewed. The fundamental principles and experimental systems of Coherent Anti-Stokes Raman Scattering (CARS), Spontaneous Vibration Raman Scattering (SVRS), Laser-induced Fluorescence (LIF), Molecular Filtered Rayleigh Scattering (FRS), Diode Laser Absorption Spectroscopy (TDLAS) etc., are presented. The measured main parameters of temperature, species concentration, density and structures in the premixed stable flame and solid fuel combustion are also given. The measured results indicate that laser spectroscopy-based diagnostic techniques can be used in premixed flame for high precision measurements, and are well suitable for the diagnostics of more complex transient combustion.

The evaluation and measurement of the beam quality for a high power manufacturing laser were established based on modern laser manufacturing. The measuring parameters, measuring principle, method, equipment and calculation were investigated. Firstly, based on the parameter analysis on distinguishing the laser beam quality at present, the relationship between beam quality and beam width was discussed by taking the beam propagation ratio(M2)and beam parameter product (Kf) for examples. Then, the proper parameters were proposed. Finally,a method based on the object of actual measurement and results were introduced. Experimental results indicate that the Kf value of DC035Slab CO2 laser and TLF6000tCO2 laser are 3.78 mm·mrad and 8.67 mm·mrad, respectively.It is concluded that the Kf value is the calculation results of hyperbolic fitting based on the actual measurement of beam radius at different positions along the laser beam propagating direction,the capability and focus ability of high power laser propagation can be reflected better,which defines well the laser performance for manufacturing systems.

A cryogenic adsorption technique was presented to replace the machinery pump and exhaust processing system,which could provide a possible way to greatly suppress the size of a discharge-driven CW HF/DF chemical laser.As the nitrogen diluent must be used instead of helium for the cryogenic adsorption pump, the efficiency of HF/DF chemical laser would be lowered down greatly. To solve the problem,a periodically arranged supersonic nozzle array composed of slit and conical holes with a 4 mm period was developed to replace the traditional single slit transverse sonic fuel injecting gain generator. Experimental results with HF laser demonstrates that the laser output and electrical-optical efficiency by designed supersonic nozzle array have been increased from 25 W to 90 W,and 0.8% to 5.9%,respectively.Furthermore,the fuel specific efficiency has a nearly fourfold increase,which is slightly higher than that from the helium diluen. Obtained results prove that the efficiency of the nitrogen diluted discharge-driven CW HF/DF chemical laser can be greatly improved by using the devel-oped supersoinc nozzle array.

A multi-cavity passive nanosecond laser pulse stretching system was designed. The system could reduce laser peak powers and avoid the laser induced plasma spark, so that it reduces background interference and improves the signal to noise ratio in combustion diagnostics. The theoretical model of the pulse-stretching process for an arbitrary number of optical ring cavities was introduced,and several key parameters that affect on pulse width, beam-splitter reflectivity, cavity length and total number of optical cavities were analyzed. Finally,the designed multi-cavity laser pulse stretcher was used in broadening the Nd:YAG laser harmonic pulse width.Results indicate that a 7.8 ns input laser pulse has been converted into approximately the output laser pulses in 17 ns, 35 ns and 72 ns, respectively.Furthermore, the laser peak power has been reduced to 9% of the original laser peak power, meanwhile,it maintains the good beam quality. The stretcher was also used in the spontaneous Raman scattering experiments, and results show it well resolves the laser induced breakdown spectroscopy of the Raman signal and achieves good results.

In order to improve the cladding quality and to control the bonding interface of the layer formed by overlapping laser cladding,the effects of parameters on the microstructure of bonding interface were studied. The results show that when scanning speed, powder feeding rate and laser power change in the range of 100-250 mm/min,6-7.5 g/min and 1 500-2 500 W, respectively, the bonding region does not appear a white layer and presents different morphologies. One of morphologies is the continuous epitaxial growth with inherited microstructures and directions, and the other is discontinuous epitaxial growth. This is related to the effects of parameters on the depth of remelting region of a shifted dendrite, the orientation and molten degree of grain of a prior layer surface, and the con-vection in the molten pool.

By using a linear CCD as the detector module, a measuring system for particle size distribution was established by laser diffraction. Based on numerical computation, the two problems in Chin-Shifrin integration particle size inversion algorithm:the divergence of inversion in a small particle size and its false peaks,were analyzed and the causes of these phenomena were explained. Then,the modification of the integration formula was proposed to resolve the divergence problem. Aiming at the particular application on Chin-Shifrin integral transform, the effective angle range of Fraunhofer diffraction approximation to Mie scattering was studied by comparing the pattern of Mie scattering and that of Fraunhofer diffraction.The numerical result show that the valid angle for diffraction approximation decreases as the angle becomes large, but the precision of the inversion has increased. Finally, this improved Chin-Shifrin inversion algorithm was used to process experimental data. The experimental result shows that the improved inversion algorithm has high precision and is suitable for applications in industry.Key words:

The seed beam smoothing experiments were performed to get a smoothing and partial coherence seed by using Amplified Spontaneous Emission(ASE) and scattering methods. The relationship between the uniformity of seed beam intensity distribution,energy,the divergence of seed beam and the beam diameter and postion was investigated based on a short pulse XeCl excimer laser.And then the factors which infulenced the parameters of the seed beam were analysed. Experimental results indicate that the lowest nonuniformity of the seed beam produced by ASE method is 2.01%, and the energy is several μJ. But the horizontal divergence of the seed beam is different from the vertical one. The nonuniformity of the seed beam produced by scattering method is 1.54%, the energy is about one hundred nJ as the divergence is 5.5 mrad, and the laser beam diffraction limited times can be adjusted from 14 to 37. Furthermore,the size of the pumping source influences the divergence of the seed produced by ASE, and the input laser energy, laser diameter on scattering board and the focus of the lens for gathering light influence the parameters of scattering seed. After being amplified, the nonuniformity of the source beam is 2.04%, and the energy is about 8.0 mJ. The results mentioned above show that the seed adapts to the high power XeCl excimer laser system.

With the purpose of investigating the millimeter order hole's formation and the drilling speed drilled by a single millisecond pulse laser, the shapes of holes in an aluminium slab drilled by a Nd: YAG Gaussian laser with 1 ms pulse width were obtained with the cutting method in an experiment. The hole depth is 1.849 mm and 2.975 mm when the laser energy is 7.9 J and 28.9 J, respectively. A semi-infinite axisymmetric model was established according to the experiment and the analytical solution of temperature in a solid phase was derived based on the thermal conduction equation. Meanwhile, by assuming that material was removed from the hole once it was melted, the function describing the hole's shape was obtained with the energy balance theory. It was found that the difference between the calculation and the experimental results becomes larger as well as the hole's depth increases with the increase of laser energy. Further investigation indicates that the variation of beam radius affects the hole's depth greatly under other unaltered conditions. Thus, the defocusing effect was induced to modify the analytical solution and obtained results are in agreemeat well with those of the experiments. Finally, the drilling speed of millisecond pulsed laser for aluminum, copper, silver and titanium were studied. The results show that drilling speed for titanium is the fastest one due to its high absorptivity for laser and poor heat conduction ability.

In order to research the performance of the laser on a focal plane array thermal imager in a wavelenth,several field range irradiation experiments were designed and the actual light path transformation of the laser beam was calculated and simulated with the corresponding beam path theoretical calculation model. In theoretical analysis,the flat-topping laser beam, optical stop formed by a laser output mirror and the optical elements in the light path were simulated by the flat-topping Gaussian function and the sum of a finite number of complex Gaussian functions, then the delivery and transformation of laser beam were calculated with the Collins diffraction formula of a paraxial optical system.In the laboratory, the laser beam disturbance on the thermal imager was implemented by placing the singlet and changing the distance between the optical element and the laser. Experimental results indicates that low power CW lasers could disturb the thermal imager and the disc of confusion on the focal plane could overlay almost approximate 30 percent of image cells.The conclusion shows that the theoretical calculation is coinciden with the experimental results well.

The frequency-dependent optical constants of GaSe∶S crystals,refractive indexes,and obsorption conficients, were measured by using the terahertz time-domain spectroscopy. By the temporal-profile measurements of the terahertz pulse, the ordinary refractive index and absorption coefficients of GaSe1-xSx(x=0,0.01,0.14,0.26,0.37) crystals in the range of 0.2-2.0 THz were obtained directly. The vibration modes of two phonons (E′(2) and E″(2)) on the absorption spectra were measured,in which their intensities and frequencies change with the doped amounts of sulfur. Furthermore, for the first time to our knowledge, the possibility of ee-e down-conversion in the THz range was demonstrated by a simulation.

The repetitive-pulsed non-chain HF lasers initiated by e-beams and fast discharges were studied respectively. The e-beam initiated HF laser characterized by an all-solid-state generator was developed. A large area repetitive uniform e-beam was obtained and the Faraday cup was used to diagnose the uniformity of e-beam into the laser gas cell. The output characteristics of the laser were studied and the maximal energy of 4.8 mJ was obtained with gas mixture C2H6∶SF6＝0.035. The e-beam initiated HF laser could operate at the repetition rate of 30 Hz. The discharge initiated non-chain HF laser was designed by using the technologies of peaking capacitor and UV pre-ionizing. The discharge characteristics and stability of SF6 gas in repetition mode were studied. The results show that the discharge includes main discharge (volume discharge) and arc discharge, between which the voltage maintains and no evident discharge is visible. The maximal output energy of 600 mJ is achieved under the condition of 28 kV charging voltage and 12 kPa gas pressure with 8% C2H6. Specific output energy of 8.5 J/l and laser electrical efficiency of 2.5% are obtained. In repetition mode, the laser can operate in the repetition rate from 1 Hz to 50 Hz. The first pulse energy is above 500 mJ, and the stable output energy of the laser at the repetition rate of 10 Hz is about 200 mJ.

In order to install an X-ray Pinhole Framing Camera (X-PFC) conveniently and run smoothly in the SG3 prototype system (SG3-PS) of Inertial Confinement Fusion (ICF), a novel type X-PFC was developed on the basis of original models and a conical barrel pinhole imaging system was desined to eliminate the stray light and to obtain the pinhole imaging in the SG3-PS. The matching parameters were evidently improved by designing a long micro-strip in new tube,which could keep the number of imagings to be still 16 frames in the limited space by using new type fluorescent screen, steady clamp method and the way of sealing up with two optics fiber plates. The save quality of new tube was improved greatly by gating pulse voltage on the screen. Furthermore,the high-voltage pulse generators and all of monitoring facilities were assembled in the cylinder barrel type vacuum seal configuration by PC104. Experiments show that all kinds of technical indexes have been upgraded when some parts of the new camera structure are redesigned and experimental results are received better.

An optical pumping source by segmented surface discharge on a Al2O3 ceramic substrate was developed to reliaze the pulse repetitive stability of surface discharge. The discharge jitter and the deviation of radiation intensity were investigated in detail under different conditions. The experimental results show that the discharge jitter mainly depends on the charging voltage, trigger pulse voltage and the distance of discharge gap,and the pulse repetition rate has a little influence on the discharge jitter in the range of 1 to 10 Hz.Furthermore, the deviation of radiation intensity mainly depends on charging voltage, and does not be affected by the pulse repetition rate and gas pressure. Normally, the discharge jitter can be less than 30 ns, and the deviation of radiaion intensity is below 2%. Research results indicate that the optical pumping source has good discharge stability.

In order to improve the drilling efficiency of glass, a drilling hole method in the glass with a long pulse laser was investigated. ZrO2 was deposited onto the glass to increase the absorption at 1 064 nm. A cone shaped hole with a depth of 1.55 m was obtained by using a Nd∶YAG laser with a pulse duration of 1 ms. The efficiency of drilling holes were studied, which shows that the efficiency reaches the maximum value when the energy density equals 6.8 kJ/cm2.Then, the possible reasons were analyzed. The mechanisms of forming the cone shaped cavity were discussed by considering the property of absorption coefficient of glass that increases with the temperature. The cylindrical holes were obtained in the glass by adding absorption materials on both sides of the glass. Finally,the effects of thermal and optical properties of the absorption layer on the drilling holes were discussed to improve the drilling efficiency. The experiment results show that the single pulse ms laser can drill holes in glass by deposition absorption layers, which provides a new way for improving the drilling efficiency.

Polymer films from dopant Nolinear Optics(NLO) polymers were prepared by the spinning and coating method,then the films were poled by the electric field polarization.The EO coefficient r33 attenuation curves of poled NLO chromophore doped in polyquinoline were measured by a lock-in amplifier technology. Relying on the EO r33 experiment curves and theoretical biexponential function models, the constant items defined as the permanent EO coefficient r33 and defined as stability ratio ζ idealistically were introduced, so that the characteristic properties of EO NLO polymer were described. In addition, the attenuations of EO coefficient r33 with relaxation in 1 300 nm and 1 550 nm wavelength were discussed to observe the changes in the characterization experiments.Obtained results show that the EO coefficient r33 is the important parameters to describe the characteristic properties of these materials, and it can directly measure the EO coefficient r33 of the poled NLO polymers in selecting the NLO materials and manufacturing the wave-guide devices.

The correlation between the Raman stretching frequency shifts of a ethyl group and the concentration of the ethanol in aqueous solution was studied, and the new methods to determine the ethanol content in aqueous solution were obtained. The Raman spectra in the range of 500~4 000 cm-1 were obtained on the Renishaw 1000 Raman spectrometer in the room temperature,which shows that the shifts of C-H stretching vibration bands give a negative correlation with the ethanol concentration. Furthermore, the simple linear regression was employed to analyze the relation between the shift of band position and the concentration, and then a futher research using Multiple Linear Regression(MLR) was performed to obtain a function between the ethanol concentration and the shifts of bands on the base of this. The results show that for both the C-H symmetric stretching vibration band and the -CH3 asymmetric stretching vibration band, there are significant linear relations between their parameters. In addition, the determination coefficient of the MLR model has reached 0.98, which shows a perfect linear relation. These results indicate that the ethanol concentration in the aqueous solution can be measured by the Raman stretching frequency shifts of ethyl group.

The combination of optical angular mutiplexing and Echelon Free Induced Spatial Incoherence (EFISI) is a best choice for the pulse compression and beam smoothing in a high power excimer laser system, which relates to the transportation and amplification of smoothed narrow laser pulse mainly. In this paper, the construction of a partial coherence oscillator by scattering method was described and primary results for pulse shaping were provided. Then, the gain characteristics for five laser amplifiers by single-pass amplifications and simulations of different output couplings were discussed, and measures to control over Amplification Spontaneous Emission (ASE) in the short laser pulse amplification was described. Finally,the Main Oscilation Power Amplifer(MOPA) chain of a single-beam XeCl laser and primary results were introduced. Obtained results show that the final output energy is 5-6 J with a pulsewidth around 10 ns and the focal spot is around 300 μm in the diameter. These results indicate that the laser chain and optical design are reasonable, which can be used as a good guide for the specific design of full scale angular multiplexed laser MOPA system.

The evaluation methods for far field optical quality of a TEA CO2 laser with a unstable resonator were researched. Based on the real data of the unstable resonator modified by the stable resonator of a high power TEA CO2 laser, three common theoretical evaluation methods were conducted to evaluate the optical quality.Obtained results were compared with that from the far field optical intensity distribution of a designed 2 kW unstable resonator laser. The analysis and comparison show that the unstable resonator can obtain a near diffraction limit and a high optical quality beam and the β factor is 4 times that of the stable resonator. Under the same power level, the far field power density of the unstable resonator is 19 times that of the stable one. Furthermore, the smaller block factor can obtain a higher power in bucket for the unstable resonator. It is concluded that the comprehensive prediction and evaluation of designed unstable resonator need to synthetically use the three theoretical methods to complete.

Based on the fracture behavior during laser irradiating brittle materials,a controlling fracture technique was used for cutting brittle materials. In order to investigate the mechanism of fracture behavior during pulsed laser irradiating single silicon, a three-dimensional finite element thermoelastic calculational model which contains a pre-existing crack was established based on the heat transfer theory. The development of the temperature field and thermal stress field were investigated during the pulse duration and the changes of stress intensity factor around a crack tip were analyzed. The simulation results show that there are two tensile stress zones induced by the laser heating zone. When the laser spot is near the edge of the silicon wafer, the larger tensile stress is induced at the edge of the silicon wafer, and when the pulsed laser scans the silicon wafer, the pre-existing crack can induce the fracture to propagate along the moving direction of the laser beam. Obtained results are well coincident with the crack expanding process reported by the literature.

In order to acquire the laser coupling coefficient of a metal plate, an inversion method was given based on measured temperature data on the rear surface of the plate. By introducing some approximate conditions, the inversion expressions of the laser coupling coefficient and the temperature on front surface were derived, and a engineering algorithm of laser coupling coefficient was obtained. The inversion algorithm was validated by using two methods. one is to calculate the 1.3 μm laser coupling coefficeint of the 30CrMnSiA by reversal method and to compare it with the experiment result in references for the same material plate;the other is to measure the temperature rise on the rear surface of the plate and to obtain the changes of the coupling coefficient with the radiation time and temperature and compare it with the measured experiment result in our experiments for the same material plate. The verified result shows that the inversal engineering algorithm is feasible and meets the requirement of the study of laser irradiation effects.

To realize 10.6/9.3 μm two-wavelength high energy laser switching output on one laser,a coating on output mirror was taken to obtain a 9.3 μm singlet output whose pulse energy was roughly equal to 10.6 μm.A two-wavelength window switching device with free shift out strucutres was designed.The statics analysis,thermal-stress analysis and the thermal-stress coupling analysis were used in the switching shift flat to get the displacement deformation by MSC.Patran/Nastran software,then the least square method was taken to get the output mirror deflection angle around the axis by Matlab software. The results indicate that the maximum stress of structure is 101 MPa,the maximum deformation of mirror is 6.95 μm,and the mirror deflection angles around the axis are 0.07″,2.92″ and 0.009″,respectively.A emission experiment for the physical device was performed,which shows that the directional relative error of two wavelength shift emission is 8.7″.The results mean that the structure can satisfy the requirements of the free shift output of two wavelength lasers for capabilities and parameters.

To explore the mechanism of the long-pulse laser interaction with semiconductor materials, a one-dimensional finite element calculational model was established to investigate the vaporization effect of the long-pulse laser interaction with the silicon. In the calculation, Enthalpy method was used to resolve the process of solid-liquid phase change, and the heat flux equation was used to analyze the energy loss of vaporization. With the certain incident laser power density and different pulse widths,the long pulse laser interaction with the silicon in the process of melting and vaporization phenomena was simulated. The vaporization velocity, temperature evolvement, and the effect of vaporization on ablation depth during and after the laser irradiation were emphatically analyzed. Furthermore, the atomic vapor induced self-focusing threshold by laser transmission was estimated to be about 0.2 W when vaporization depth was about 0.5 μm,which was far less than the long-pulse laser power. Therefore, the follow-up laser will cause optical self-focusing phenomenon by vaporization in the long pulse laser interaction with the silicon, obtained results can provide the theoretical basis for the research on the mechanism of the laser interaction with the silicon.

A molecular Filtered Rayleigh Scattering (FRS) diagnostic system was demonstrated to measure thermodynamic properties in combustion environments. The diagnostics system was composed of a narrow line width laser, a molecular/atomic absorption filter and a collection device such as ICCD. The absorption filter was used to modify the spectra of the Rayleigh scattering signal from the flow field illuminated by a laser sheet from a Nd:YAG pulsed laser. The laser was tuned to an absorption line of iodine vapor contained in the filter. This caused Mie scattering and background scattering from solid particles and strong absorption on the surface while much of Doppler broadened Rayleigh scattering was transmitted through the filter. The thermodynamic parameters were deduced from the measured transmission of the molecular Rayleigh scattering. The FRS diagnostic system and the iodine filter cell were described. On the basis of diagnosing FRS image and measuring iodine vapor absorption spectrum, the 2D temperature and density fields of methane/air premixed flame were obtained. The measured density at 15 mm above the burner surface is 0.19 kg/m3, and temperature is (1 827±84) K, which is good agreement with the results measured by using CARS method in the same condition. The uncertainty of temperature measurement by FRS is less than 8%. Furthermore, FRS technique was used to diagnose the atomization steam and supersonic exhaust flows. The results turbulence structures on the area of laser action were obtained. These demonstrate the abilities of the FRS technique to measure temperature and density fields and to enhance flow visualization in a combustion environment.

A kind of beam shaping technique was presented to improve the beam quality of a semiconductor laser and to achieve the beam splitting,translating,and rearranging by a parallel plate glass stack.The experiment uses a 20-layer 808 nm semiconductor laser array designed by ourselves with the output power of 60 W per bar,19 light-emitting points of 1 μm×135 μm each and 30% filling factor to expand beam at a slow axis through a telescope system,and also uses a focusing lens to focus on both the slow axis and the fast one at the same time. Experiments show that the technique can achieve the 1 kW output power on the focal plane,focused spot of 1 mm×1 mm and coupling efficiency of 90%,which basically satisfies the needs of laser cladding and welding.

A measurement system was established to study the laser pulse irradiation effects on a plane array Si-CCD at the wavelength of 532 nm and the pulse duration of 170 ps. Experiments on Si-CCD under picosecond laser irradiation were carried out,the typical experiment phenomena were observed and the corresponding energy density thresholds were measured. Furthermore,the microstructure of damaged CCD was observed，and the damage mechanism was analyzed. It was demonstrated that the most severe failures could result from the malfunction of CCD circuits. Experiments on a Si-CCD by laser pulses at the wavelength of 532 nm,800 nm and the pulse duration in 10 ns， 150 fs were carried out,respectively,then the thresholds with different pulse durations were measured and compared. Experimental results indicate that the Si-CCD is disturbed when the laser energy density is between 10-8-10-3 J/cm2,and the permanent damage of Si-CCD is observed when laser energy density is larger than 10-1 J/cm2.

To investigate the similarity on thermo-mechanical effects induced by different pulsed beams, and also to give a reference for the experimental research of thermal and mechanical effects under X-ray radiation using simulation method of laser irradiation, the similarity and distinction between impulse coupling with an aluminum target by the pulsed ultraviolet laser(0.308 μm) and X-ray were analyzed. Firstly, the contrast of the mechanism of thermo-mechanical effects between two pulsed beams was compared. Then, a comparative analysis for the quantity of blow-off impulse induced by two pulsed beams coupling with Al materials was performed in lower energy flux (<100 J/cm2) by means of theory and experimental methods. The results show that the generation mechanisms of blow-off impulse are similar in lower energy flux (<100 J/cm2) for the pulsed ultraviolet laser and X-ray, because there are not a phenomenon of plasma shield. The quantity of impulse by these two pulsed beam irradiation has the same order of magnitude of impulse (<102) in same energy flux. Therefore, the two pulsed beam effects are comparable within a certain range.

In order to improve the laser pulse contrast, an optical Kerr shutter was used to select the main pulse to restrain the noise of the main pulse.The laser was split into two beams. One of them was used as a gate light to control the optical Kerr shutter,and the other was to be cleaned. The two beams were spacial crossed in optical Kerr materials. The open time of the optical Kerr shutter was controlled to select the main pulse,while the light outs of the shutter were blocked. Therefore, the laser pulse contrast was enhanced.The experiment result showed that the duration and the transmission ratio of the optical Kerr shutter are about 570 fs and 17%,respectively and the pulse contrast has been enhanced by 104 times. The conclusion is that the optical Kerr shutter technology can efficiently enhance laser pulse contrast.

A 500 fs, 248 nm ultra-short UV laser system for high speed recording devices and scintillators’ fluorescent excitation was introduced in the paper. The central part of the laser system is a Distributed Feedback Dye Laser(DFDL),namely, a dynamic image of coarse grating. The image length and the index of dye solution give the shortest pulse duration and changing the pitch of the grating results in a tunable spectrum. In experiments the working wavelength of the DFDL was adjusted to 496 nm and frequency doubled to 248 nm, which was match to that of the KrF excimer amplifier. The off-axis three pass amplification schemes and low saturation energy density of the excimer laser media made the intensity profile of the laser beam faily uniform, which was very attractive for the calibration of a high-speed recording device.An experiment to measure the fluorescent characteristics of a thin film ZnO∶Ga scintillator under UV laser excitation was demonstrated with the laser system. The interference of the scattered laser and the weak fluorescent signal was solved by using a collective imaging lens and a monochrometer.Obtained results show that the fluoresce spectrum is in the 380 nm to 410 nm with the central peak at 392 nm, and the fluorescene time of the scintillator is about 80 ps. Finally,the factors which may affect the measuring results were also discussed.

An experiment of 975 nm continuous wave laser irradiating carbon-fiber reinforced resin composites was studied, while the front surface of a target was with and without tangential airflow loadings. The results show that the dynamic responses are obviously different for two different cases.While the front surface of the target is without tangential airflow loading,the ejected inner pyrolysis products ignite surface combustion which is accompanied by dense smoke and flame after laser irradiation for 1.28 s.While the front surface of the target is with tangential airflow loading, there is not obvious combustion flame, but a burn-like bright spot is in the laser-irradiated zone and a little particles spill into the air intermittently. Analysis indicates that the out overflows of pyrolysis products will inhibit the diffusion of oxygen to the target surface, which has a protective effect on the carbon fiber. The presence of tangential airflow not only undermine the protective effect of pyrolysis products on the carbon fiber, but also promote the diffusion of oxygen to the surface. Therefore, the loading of tangential airflow will result in the carbon fiber suffered from oxidative ablation at the low temperature (850 ℃).

In order to investigate the mechanism of slow-light effect via stimulated Brillouin scattering (SBS), the occurrence of the anti-Stokes scattering of Stokes light and the relationship between the anti-Stokes scattering and the mechanism of slow-light via SBS were researched. It is proved that the Stokes light can also be scattered by Brillouin ultrasounds besides the pump light in SBS. The scattering is anti-Stokes, and is a reversal process of the Stokes scattering of the pump light. Therefore, the pump and Stokes lights in SBS experience a back-and-forth scatterings in Brillouin sound fields. On this premise, a model was presented to depict the slow-light effect, in which the optical distance of Stokes wave was enhanced due to the back-and-forth scatterings and the pulse was slowed down as a result. Experiments show the deduced delaying time for the Stokes pulse given by the model agrees with former results. Which suggest that the Stokes light can be anti-Stokes scattered in Brillouin scattered by Brillouin sound fields and also that the enlarged optical distance due to multiple scatterings would be the origin of light slowing in SBS.

Light scattered from the imperfect surface of a primary mirror in a reflective optical system will result in the in-field stray light and reduce the image contrast. This paper presents a simple method to process the scattering of the primary mirror.A Harvey Bidirectional Scatter Distribution Function(BSDF) model is used to characterize the angular distribution of scattered light from the mirror, and the scattering distribution at the focal plane of the primary mirror is derived. The characteristic radius centered by the image point can be achieved when the intensity of scattering equals that of diffraction. It is found that for the given optical system, the characteristic radius only depends on the scattering characteristic of the primary mirror. The intensity distribution at the focal plane is divided into two regions by the characteristic radius. The intensity of diffraction is larger than that of scattering intensity,which makes the dominant contribution to the saturation effect when the distance from the image point is less than the characteristic radius, conversely, the scattering is the main factor to the saturation effect when the distance from the image point is larger than the characteristic radius. For a primary mirror with a focal length of -757 mm, an radius of 115 mm and the rms roughness of 10 nm at the wavelength of 550 nm, the characteristic radius is 0.843 mm approximately. These conclusions are conductive to the analyzing and explaining of the saturation effects in an optical system irradiated by a intense light.