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41.
Spectral Characteristics of Miniature Two-Longitudinal-Mode Optically Pumped FIR Laser 总被引:1,自引:0,他引:1
Xiaorong Zou Xizhang Luo Jiayin Qin 《International Journal of Infrared and Millimeter Waves》1998,19(11):1561-1570
With the assumption that the pump source was two-longitudinal-mode, the semiclassical density matrix equation of a three-energy-level system was solved. By means of iteration method, the spectral characteristics of miniature two-longitudinal-mode optically pumped NH3 far-infrared cavity laser, which was pumped by CO2-9R(16) line, were calculated numerically. The influences of operating parameters on laser spectrum were studied intensively. 相似文献
42.
D. Dangoisse J. Wascat J. M. Colmont 《International Journal of Infrared and Millimeter Waves》1981,2(6):1177-1191
A large number of emissions is obtained in the submillimeter and near millimeter range with the (H2CO)3 laser optically pumped by a CO2 laser. A study of the microwave absorption spectrum of the molecule carried out simultaneously with the submm analysis allows us to assign six of the laser lines in thev
5 excited state of the molecule and to determine the rotational constants and vibrational energy ofv
5. 相似文献
43.
设计并优化了一种用808nm的大功率激光二极管为抽运光源,In0.09Ga0.91As量子阱结构为增益介质的920nm光抽运半导体垂直外腔面发射激光器。运用有限元方法,对激光器的电特性方程和光特性方程求自洽解,计算了器件各种特性参量。分析了单个周期内不同阱的个数(1,2和3)、不同阱深、不同垒宽、不同非吸收层组分、不同非吸收层尺寸条件下,器件性能的改变,特别是模式、阈值和光-光转换效率的改变,从而选择一个最佳的结构。 相似文献
44.
M. R. Philpott A Girlando W G. Golden W Knoll J. D. Swalen 《Molecular Crystals and Liquid Crystals》2013,570(1):335-351
The vibrational spectra of monolayer assemblies of cadmium arachidate on smooth and rough silver substrates were obtained by surface infrared and surface plasmon enhanced Raman spectroscopy. The assemblies were laid down by the Langmuir-Blodgett deposition technique. For Raman scattering the intensity of the incident light was enhanced by grating coupling to surface plasmon optical modes of the metal or to localized plasmon modes in the case of rough surfaces. It was found that the different vibrational frequency regions corresponding, for example, to C-C and C-H stretching modes, were enhanced by selecting different scattering angles for collecting the inelastically scattered light. The Raman spectra of monolayer assemblies in contact with silver islands showed evidence of conformational disorder, i.e., the alkyl chains of some molecules were not in the all-trans configuration. In contrast, the infrared spectra did not show evidence of similar disorder. These observations were explained by assuming that the infrared photons sensed the majority undistorted molecular species, while the Raman photons came from a distorted minority species located in regions where optical electromagnetic fields were enhanced by shape plasmon resonances of the rough silver surface. 相似文献
45.
Optically stimulated luminescence (OSL) of pure analytical sodium chloride (NaCl) was studied. Performing series of CW-OSL (continuous wave OSL) readouts it was found that subsequent CW-OSL decay, after some delay, starts from significantly higher intensity level than the final intensity of the previous readout. To study this ‘regeneration effect’ a new type of measurements was implemented – the variable delay OSL (VD-OSL) method. The idea of VD-OSL is explained – it allows to study OSL kinetics at very long time scale. VD-OSL data confirm coexistence of two effects in NaCl – regeneration and fading of the OSL signal. After partial CW-OSL readout, regeneration predominates in the short time scale of the order of 103 s. Then, fading becomes dominant. The same measurements were applied to commonly used Al2O3:C material as well. Nevertheless, the results do not show such behavior at the studied time scale. Theoretical arguments are presented that the regeneration mechanism cannot be explained on the basis of the simple trap model. 相似文献
46.
The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. 相似文献
47.
The dependence of optically stimulated luminescence (OSL) and thermoluminescence (TL) response due to crystal phase in Cu and Cu,Mg-doped Na2SO4 was studied. Study shows that the slowly cooled samples which crystallize in phase V show good OSL sensitivity whereas the quenched samples of Na2SO4 which crystallize in phase III irrespective of doping show no OSL sensitivity. However, during storage when phase III samples get converted to phase V, samples show OSL sensitivity comparable to freshly prepared samples in phase V. Hence, it is observed that TL–OSL properties of doped Na2SO4 are phase dependent .This study will be helpful in developing OSL phosphors in which phase plays an important role in deciding the desired properties. 相似文献
48.
O. I. Kolodiazhnyi E. V. Grishkun S. Sheiko O. Demchuk H. Thoennessen P. Jones R. Schmutzler 《Russian Chemical Bulletin》1999,48(8):1568-1573
Chiral C2-symmetrical dialkyl phosphites and C3-symmetrical trialkyl phosphites, derived from (−)-borneol, (−)-menthol, and 1,2∶5,6-di-O-isopropylidene-α-d-glucofuranose, were studied as the starting reagents for the preparation of chiral organophosphorus compounds. The reactions
of C2-symmetrical dialkyl phosphites and C3-symmetrical trialkyl phosphites with aldehydes and amines or aldehydes are accompanied by asymmetrical induction at the α-carbon
atom to yield optically active α-aminoalkylphosphanates or α-hydroxyalkylphosphonates, respectively. The stereoselectivity
of the reaction depends on the structure of the starting compounds and the reaction conditions.
Translated fromIzvestiya Akademii, Nauk, Seriya Khimicheskaya, No. 8, pp. 1588–1593, August, 1999. 相似文献
49.
The output intensity of optically pumped NH3 molecules far-infrared laser (NH3-OPFIRL) was calculated by solving the density matrix equation and by means of iteration method. Meanwhile, the spectral characteristic of AC Stark splitting was studied. Finally, the F-P interferogram of NH3-OPFIRL pumped by CO2-10R(8) line was measured. The experimental results were in good agreement with the theoretical calculation results. 相似文献
50.
Tsutomu Oishi Kenjiro Onimura Yukio Isobe Hiroaki Yanagihara Hiromori Tsutsumi 《Journal of polymer science. Part A, Polymer chemistry》2000,38(2):310-320
Asymmetric anionic homopolymerizations of N‐substituted maleimide (RMI) bearing bulky substituents [R = benzyl, diphenylmethyl (DPhMI), 9‐fluorenyl (9‐FlMI), triphenylmethyl, (diphenylmethyloxycarbonyl)methyl, (9‐fluorenyloxycarbonyl)methyl] were carried out with complexes of organometal compounds (alkyllithium, diethylzinc) with six chiral ligands to obtain optically active polymers. The chiroptical properties of the polymers were affected strongly by the substituents on nitrogen in the maleimide ring, the organometal and chiral ligands. Poly(DPhMI) initiated by an n‐butyllithium/(−)‐sparteine (Sp) complex showed a positive specific rotation ([α] +60.3°). Poly(9‐FlMI) prepared with a florenyllithium/Sp complex exhibited the highest specific rotation (+65.7°). The specific rotations of the poly(RMI) obtained were attributed to different contents between the stereogenic centers (S,S) and (R,R) based on threo‐diisotactic structures of the main chain. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 310–320, 2000 相似文献