共查询到20条相似文献,搜索用时 62 毫秒
1.
The heat produced in conjunction with the processes of stimulated Raman scattering and four-wave Raman mixing in hydrogen
was measured by photothermal refraction spectroscopy. Many vibrational, rotational, and vibrationally shifted rotational Raman
lines are exclusively/simultaneously generated by changing the polarization of the laser beam and the hydrogen pressure. Thermal
loss occurs predominantly from vibrational Raman scattering, which can be ascribed to a large Raman shift frequency of 4155 cm-1 for the vibrational transition. In contrast to stimulated Raman scattering, little or no thermal loss is observable during
the process of four-wave Raman mixing.
Received: 12 April 1999 / Revised version: 12 July 1999 / Published online: 20 October 1999 相似文献
2.
Simultaneous stimulated Raman scattering at the 992 cm–1 and the 3063 cm–1 line of benzene is observed by mode-locked ruby laser pulse excitation. The double line stimulated Raman scattering is initiated by self-focusing. The influence of small-scale self-focusing, self-phase modulation, and cross-phase modulation on the double line stimulated Raman scattering is discussed. At low pump pulse intensities, before the onset of small-scale self-focusing, the steady-state Raman gain factors of both Raman lines are determined by Raman energy conversion efficiency measurements. 相似文献
3.
4.
类胡萝卜素是含有9个CC共轭双键的短链多烯类生物分子. 特殊的分子结构, 使其不仅在光采集, 光防护, 防癌, 抗癌等生物学领域有重要应用, 而且在分子导线, 光开关, 滤光器等光电器件研制中也有重要的非生物学应用. 本文对它的分子光谱进行研究和总结, 结果表明, 类胡萝卜素具有宽带荧光, 将其用于荧光增强受激拉曼散射可以获得宽带受激拉曼散射; 电子能隙随温度降低而收缩, 电子吸收光谱红移, 这特性使它能研制优质半导体元件; 极大的拉曼活性和三阶非线性系数, CC键基频拉曼散射截面可以比普通分子大10个数量级, 和频、倍频拉曼散射强度也很高, 低温下与基频强度比可达0.5. 类胡萝卜素分子的这些光谱特性对多烯类分子结构、性能研究及其在非生物学中的应用有重要参数价值. 相似文献
5.
The propagation constant of the stimulated Raman process and Raman susceptibility measurements in KDP are reported. The stimulated Raman scattering due to 915 cm-1 and 93 cm-1 vibration in KDP has been experimentally observed. 相似文献
6.
R. Ebert H. Pascher G. Appold H. G. Häfele 《Applied Physics A: Materials Science & Processing》1977,14(2):155-159
We report for the first time stimulated magneto-Raman scattering inp-type InSb. Two different Raman scattering processes were observed. The first one has a Raman shift of about 2cm−1/kG and is observed at magnetic fields up to 30kG. The other one is observable only at high magnetic fields above 30kG and
shows Raman shifts between 1.2cm−1 and 3.0cm−1 with a tuning rate of about 0.2cm−1/kG. The first process can be interpreted either as spin-flip Raman scattering by photo-excited electrons in the conduction
band or as Raman scattering by holes in the valence band involving transitions from heavy to light hole states. The other
Raman shift observed seems to occur on account of transitions between the heavy hole ladders. 相似文献
7.
Transient stimulated Raman scattering is used for the generation of a frequency shifted picosecond light pulse; part of this Raman shifted pulse is subsequently coherently scattered at a material excitation of a second Raman cell. Starting with the second harmonic pulse (tp = 4 ps) of a mode-locked Nd : glass laser system, both the stimulated and the coherently produced pulses have durations of 2.3 ps at different wavelengths. By the appropriate choice of the Raman medium pulses between 13 000 and 21 000 cm-1 can be generated. The coherent generation process minimizes the temporal jitter between the two pulses and allows to obtain a high time resolution of better than 0.3 ps in excite and probe experiments. 相似文献
8.
本文叙述了用调Q倍频YAG脉冲激光照射α-LiIO3晶体,在不同的散射配置下,获得了各种散射谱图。实验表明,当用e光入射时,可以比用o光入射激发起更多不同模的晶格振动;获得了E2模的很强的一阶、二阶斯托克斯散射线和反斯托克斯散射线,E1模Polariton的一阶、二阶、三阶斯托克斯线和反斯托克斯线,还获得了反斯托克斯频率区一条频移为469cm-1的新线,认为是不同模的Polariton之间的相互作用引起的。最后,提到实验中初步观察到的晶体拉曼活性的“疲劳现象”。
关键词: 相似文献
9.
V. P. Zakharov I. A. Bratchenko Yu. A. Khristoforova D. V. Kornilin 《Optics and Spectroscopy》2013,115(2):182-186
A mathematical model of the interaction of optical radiation with skin tissues is developed taking into account stimulated Raman scattering. Numerical experiments show that the backscattering spectra possess specific features typical of skin pathologies. It is shown that the pathology type can be determined from an analysis of the differential ratios of the Raman scattering intensities at 1271 and 1663 cm?1 to the intensity in the region of 1454 cm?1. It is found that the difference in the differential ratios of the Raman scattering intensities for pathologically changed and normal layers may exceed 40%. 相似文献
10.
M. V. Zhuravlev 《Optics and Spectroscopy》2009,106(4):537-544
The threshold intensity and the combination frequencies for photothermal vibrational instability in high-Q aqueous aerosol droplets in the two-mode regime have been calculated. The selection rules for coupling electromagnetic and temperature modes in a droplet are obtained. A comparative analysis of the threshold excitation intensities of photothermal vibrational instability, stimulated Mandelstam-Brillouin scattering, and stimulated Raman scattering in droplets is performed. It is shown that photothermal vibrational instability in the two-mode regime can be developed at a pump intensity of about 104 W/cm2 for droplets with radii of 2–20 μm for a pump wavelength of 0.532 μm. A method of remote measurement of the microphysical droplet parameters from the additional periodic temperature shift of droplet eigenfrequencies in the spectrum of stimulated Raman scattering and lasing is proposed. 相似文献
11.
The efficiency of hydrogen evolution from transformer oil into a vacuum and into air under normal pressure is studied for the case when the oil is exposed to focused ultrasonic radiation. The study is performed by the method of spectroscopy of biharmonic-pumping coherent anti-Stokes Raman scattering (CARS) based on stimulated Raman scattering (SRS). Ultrasonic radiation at a frequency of 1.76 MHz is excited by a spherical piezoceramic transducer mounted on the bottom of the vessel and is focused on the surface of the oil. This causes the intense stirring of the oil with the formation of a fountain. The room-temperature diffusion coefficient of hydrogen in the transformer oil, 10−7 m2/s, is found by approximating experimental data by a theoretical relationship for hydrogen evolution into air. It is shown that ultrasonic radiation with a power density of 2.2 kW/m2 accelerates diffusion processes ten-to fifteen-fold. 相似文献
12.
13.
M. V. Zhuravlev 《Optics and Spectroscopy》2008,104(2):196-202
The threshold conditions of excitation of temperature oscillations in high-Q water aerosol droplets have been studied under the conditions of slow evaporation. Selection rules have been obtained for interacting modes in a droplet. The threshold intensity of excitation of temperature oscillations has been analyzed in comparison with the threshold intensity of stimulated Brillouin and stimulated Raman scattering in a droplet. It is shown that, in the three-mode regime, the temperature oscillations can be excited at a rather low pumping level (about 10 W/cm2). A method is proposed for the remote measurement of the microphysical parameters of a droplet from the periodic temperature shift of eigenfrequencies of a droplet, the threshold intensity of excitation of temperature oscillations, and the thermal Raman frequency. 相似文献
14.
New methods of generation of anti-Stokes radiation of stimulated Raman scattering in media with changeable parameters of the third-order nonlinearity χ(3) along the longitudinal coordinate are proposed. The conditions of obtaining phase quasi-matching in different media and reaching the maximum efficiency of conversion into the anti-Stokes component of stimulated scattering are determined by numerical methods. The dependence of the efficiency of energy transfer from the pump wave to the anti-Stokes wave on the ratio of intensities of the pump and Stokes waves at the input of the medium is studied. The models of the media in which the efficiency of generation of anti-Stokes radiation exceeds 30% are obtained. The results of the investigation can be used for the development of new efficient nonlinear optical devices upconverting the laser radiation frequency. 相似文献
15.
16.
采用两束圆偏振啁啾飞秒激光脉冲,非共线相干激发三原子分子CS2液体. 在相位匹配的方向上,探测到由CS2频率为397 cm-1的振动模式产生的强度对称分布的相干反斯托克斯拉曼散射(CARS)信号和相干斯托克斯拉曼散射(CSRS)信号. 当调整两束激发光的圆偏振状态时,CARS,CSRS信号的强度、偏振、波长均发生规律性的改变:CARS,CSRS信号的强度分布反映了CS2 在不同极化状态下的受激拉曼散射截面大小;信号光的
关键词:
啁啾脉冲
相干反斯托克斯拉曼散射(CARS)
相干斯托克斯拉曼散射(CSRS)
2')" href="#">CS2 相似文献
17.
Guang S. He Yiping Cui Paras N. Prasad 《Journal of Experimental and Theoretical Physics》1997,85(5):850-856
The spectral structure of backward stimulated scattering from a 10 cm-long CS2-liquid cell is investigated by using Q-switched 10-ns and 532-nm laser pulses with different spectral linewidths. Under a narrow spectral line (∼0.1 cm−1) pump condition, very strong sharp lines near the pump wavelength (λ
0) position and the first-order stimulated Raman scattering (λ
s1) position can be observed. However, under a wide line (≈1 cm−1) pump condition, only a strong and superbroadening spectral band can be observed mainly in the red-shift side of the pump
wavelength. The different spectral features under these two conditions can be explained by a competition between stimulated
Brillouin, Raman, and Rayleigh-Kerr scattering. Under both pump conditions, the broadening spectral distributions are not
consistent with the predictions given by stimulated Rayleigh-wing scattering theories, but can be interpreted well utilizing
the theoretical model of stimulated Rayleigh-Kerr scattering.
Zh. éksp. Teor. Fiz. 112, 1563–1573 (November 1997)
Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor. 相似文献
18.
T. Tillert P. Zimnas K. F. Renk 《International Journal of Infrared and Millimeter Waves》1996,17(6):1011-1021
Using a continously tunable pulsed 20-atmosphere CO2 laser as a pump source, we generated pulses of mid-infrared radiation, partly tunable in frequency intervals in the range between 200 and 900 cm–1 via stimulated Raman scattering in gaseous ammonia. As a Raman cell we used a multiple pass cell. We observed for14NH3 and15NH3 laser lines at 52 different frequencies with 39 lines observed for the first time. Tuning ranges up to 150 GHz and peak powers of several MW were achieved. The quantum efficiency reached 40 %. 相似文献
19.
Redistribution of the elastic and Raman channel intensities in the Mössbauer resonant scattering spectrum can be controlled by the radio frequency (rf) stimulated quantum interference of gamma-transition amplitudes. More general expressions for each channel intensity are written out exactly taking into account the influence of the rf field. Results of calculations for the simple three-level scheme can be easily generalized to the case of 57Fe isotope in magnetic materials. 相似文献
20.
We report the first measurement of phonon surface polariton (s.p.) dispersion by a non-forward Raman scattering geometry. The Raman scattering from surface modes was excited by the evanescent electromagnetic wave produced by total reflection at the interface between two transparent media. This Raman Scattering excited in condition of Total Reflection, RSTR, has been applied to the NaClO3-sapphire interface for studying the surface polariton dispersion in the gap between the TO frequency at 966 cm-1 and the LO frequency at 983 cm-1 of sodium chlorate. Comparison is made between the experimental and theoretical dispersion curves. 相似文献