[en] Second harmonic generation(SHG)is widely used process in nonlinear optical spectroscopy. If the input light field is Gaussian beam, the dynamics of SHG is determined by the power of the input beam, the spatial shape of the input beam, its confocal parameter, the Poynting vector walk off length, the phase matching condition and so on. Our goal in this study is to investigate the spatial filtering process by aperture, the spatial shape of the focused input fundamental beam and its confocal parameter. Particularly we study the power characteristic of cw SHG for the periodically poled lithium niobate

[en] This proceedings contains articles of the 15th International Symposium on Laser Spectroscopy. It was held on November 13-14, 2008 in Daejeon, Korea. This proceedings is comprised of 7 lectures. The main subject titles of lecture are as follows: High energy density science 1, High energy density science 2, Laser spectroscopy and nuclear applications 1, Laser spectroscopy and nuclear applications 2, Extreme sources and application 1: X-ray, Extreme sources and application 2: THz, Laser acceleration (Yi, J. H.)

[en] Over the decades, there were many applications of the magneto optical trap (MOT), and also the MOT system itself has been studied on interesting phenomena such as the self sustained oscillation, collective behavior, etc. We reported spontaneous symmetry breaking (SSB)of the atomic population between two attractors formed by parametric excitation. SSB has the various and complex physical phenomena such as collective behavior in SSB. The collective behavior in MOT usually consists of attenuation force (shadow effect)and radiation trapping force. Since atoms in parametrically driven system are vibrating along two attractors, collective effects are expected to play different roles from usual MOT system. When the population symmetry is recovered by decreasing the total number of atoms, we could observe the shift of positions of two attractors as shown in Fig. 1. We think this shift can be understood in terms of attenuation force

[en] Fluorescence excitation (FE)and resonance enhanced multiphoton ionization (REMPI)spectra were measured for diphenylsilane (DPS)cooled in pulsed supersonic expansion of He in the range 262.2∼271.7nm. A CIS/6 31G(d) calculation on DPS predicts four low lying states having the origins at 49,954, 50,031, 50,866, and 51,395cm"-1", the origins presumably corresponding to the experimental values of 37,099, 37,644, 37,724, and 38,036cm"-1"determined in the present study. The vibrational bands above the electronic origin have been assigned on the basis of vibrational frequencies of the S"1"state of the molecules at the geometry optimized at the HF level using the CIS/6 31G(d) method

[en] Photodissociation of dodecamethyl cyclohexasilane (DDMCHS) has been investigated in the range from 262 to 290nm in a supersonic molecular beam. We measured a fragment excitation spectra and a LIF excitation spectrum, which are very similar to each other. We observed various daughter ions of Si"6"Me"11""+", Si"5"Me"9""+", Si"4"Me"9""+", Si"3"Me"7""+", Si"3"Me"6""+", Si"2"Me"3""+", and Si"2"Me"2""+"in the resonance two photon ionization mass spectra. The occurrences of the consecutive bond scissions and rearrangements with the aid of excess energy accumulated by additional photon absorption after the two photon ionization of DDMCHS molecule could explain the formation of the various ionic products

[en] Recently we have fabricated an InGaN based 460nm light emitting diodes (LEDs)integrated with microlens arrays made of UV curable optical adhesive and observed an enhancement of LEDs light output. This light output enhancement effect from the integrated microlens obtained under chip level LED without a packaging, however, might disappear in commercial LEDs after a packaging process is similar to that of a general UV curable optical adhesive. In this presentation, we fabricated a microlens arrays onto an InGaN LEDs using UV curable optical adhesive of a relatively high refractive index and then fabricated a packaged LEDs molded with an epoxy of a general value of refractive index. We observed the enhancement of light output in the packaged LED with microlens compared with the conventional packaged LED and therefore confirmed that the light output enhancement effect from the integrated microlens is still preserved in a final LED structure after a packaged process

[en] We have applied a coherent scattering microscopy (CSM)system to the analysis of aerial images for extreme ultra violet (EUV)masks. Measurements of aerial images for sub 22nm node were performed. Results for critical dimension (CD)measurements showed that reliable actinic CD measurements were possible even down to 12nm node using the CSM system. Detailed descriptions of the system and analysis procedures will be given together with the analysis results for line and space and contact hole patterns of EUV masks for various technology nodes

[en] A mobile molecular Doppler wind lidar at an eye safe 355nm wavelength based on double edge technique for wind measurement from 10km to 40km altitude is being built in Hefei, China. As the key component of the Doppler lidar, the receiver sub system is designed carefully. A triple Fabry Perot etalon is used as the frequency discriminator whose parameters are optimized. The thermal and mechanics stabilities are considered during the receiver design. The designed receiver system is very compact and stable, which could be embedded into a standard 19 inch socket bench with 21 inch length. With this new king of receiver, the optical alignment is easy and the stability of the etalon transmittance which is of great importance to the wind measurement would be improved

[en] We have studied the Hanle spectrum in the paraffin coated Rb vapor cell. The spectrum was observed by using one external cavity diode laser in the Λ type scheme between the Zeeman sublevels of the F"g"=2→F"e"=1 transition. In Hanle spectrum, we could observe the dual structured spectrum in the paraffin coated vapor cell. Figure 1 shows the difference of transmittance according to the direction of the magnetic field. The minimum value of transmittance is about 66% of the maximum transmittance. When the z direction magnetic field applied, the signal shifted like figure 2. The magnitudes between the peaks are about 22.5mG. The narrow linewidth of dual structured signal was measured approximately 400Hz. We investigated the dual structured lineshape as a function of magnetic field, laser power and analyzer's angle

[en] Fast neutrons were generated from a deuterated polystyrene (C_8D_8)solid target by using an ultraintense Ti:sapphire laser with a pulse output power of 10TW of 30TW. During the experiments, the laser pulse width was 27 fs and the prepulse and the ASE pulse widths were reduced to be less than 1 ns. The fast neutron yields were tried to be measured using CR 39, plastic and liquid scintillation detectors, and a gated scintillation detector with a channel photomultiplier. We report the preliminary results on the measured neutron yields and related difficulties in measuring laser produced neutrons