共查询到20条相似文献，搜索用时 0 毫秒
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本文从拉曼峰强出发,求得了反-2,3-环氧丁烷分子的拉曼键极化率,明确了拉曼激发下电荷的分布的信息.还从旋光拉曼(Raman optical activity,ROA)谱的峰强,求取了该分子的旋光拉曼键极化率.由分子手性中心的C-H产生的偶极矩与拉曼激发过程中,电荷流动产生的跃迁磁偶极矩的耦合,来理解旋光拉曼活性产生的机理.分析表明,旋光拉曼活性分子手性中心的C-H键两侧的旋光拉曼极化率符号相反,显示着手性分子局域的不对称性.还得到了对称和反对称坐标的键极化率和旋光拉曼极化率,并且从对称性的角度,即C2群的不可约表示,讨论了这些极化率的内涵. 相似文献
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通过对大量文献的调研，本文分四个部分对手性物质的旋光现象及振动光活性进行了较为全面的介绍，重点介绍了拉曼光活性ＲＯＡ（ＲａｍａｎＯｐｔｉｃａｌＡｃｔｉｖｉｔｙ）产生机理、研究状况及对其研究的意义。 相似文献
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A new circularly polarized (CP) Raman spectrometer is described that demonstrates simultaneous acquisition of all four forms of circular polarization Raman optical activity (ROA). The instrument is a design extension of a commercially available back scattering circular polarization (SCP) ROA spectrometer. Circular polarization of the incident beam is introduced with a quarter‐wave plate, and a half‐wave plate alternately positioned in and out of the beam controls the modulation between right circular polarization (RCP) or left circular polarization (LCP) states. Combining this modulation with the simultaneous detection of RCP and LCP scattered Raman radiation allows the measurement of incident circular polarization (ICP), SCP, in‐phase dual circular polarization(DCPI) and out‐of‐phase DCPII‐ROA. In addition, three different forms of backscattered Raman spectra, namely unpolarized, highly polarized, and depolarized Raman spectra, as well as a degree of circularity spectrum are obtained. The performance of the new all‐CP ROA spectrometer is evaluated with neat α‐pinene and aqueous hen lysozyme solution. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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石英晶体右旋光与左旋光折射率差的温度特性 总被引：1，自引：1，他引：1
利用Jones矩阵,从理论上分析了石英晶体的旋光特性。在-10～60℃的温度范围内,实验测试了石英晶体的旋光角随温度的变化关系,并得出了石英晶体右旋圆偏振光与左旋圆偏振光折射率差随温度的变化关系。结果表明,对单色光来说,石英晶体右旋光与左旋光折射率差随温度的升高而增加,也就是说,石英晶体的旋光率随温度变化的这一特性是由晶体的右旋圆偏振光与左旋圆偏振光的折射率差随温度的变化引起的。 相似文献
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Circularly polarized luminescent (CPL) materials have emerged as new advanced optical and photonic materials. While many efforts have been devoted to the organic CPL materials, it still remains a challenge to fabricate CPL active inorganic materials due to the difficulty in the introduction of the chiral units. Here, a simple approach for achieving CPL active inorganic persistent phosphor materials is reported. By modifying the inorganic persistent phosphor materials with enantiomeric cysteine via ball milling, the inorganic circularly polarized phosphorescence (CPP) materials with long afterglow characteristics are fabricated. Moreover, the circular polarization of the obtained phosphorescent materials can be controlled by the molecular chirality of the cysteine. The dissymmetry factor (glum) of the CPP materials can be up to 10−2. It is envisaged that this approach will afford a new insight into the designing of the inorganic functional chiral phosphorescent materials. 相似文献
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Theoretical analysis on double Rayleigh backscattering noise in optical fibreRaman amplifiers and its suppression 
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下载免费PDF全文 In this paper, amplified double Rayleigh backscattering noise (DRB) in the optical fibre Raman amplifier is analysed. Expressions are presented for both forward pumping and backward pumping schemes. Calculation is performed to show the effective suppression of DRB noise by employing an optical isolator. The optimal position for the isolator is determined and is found to be insensitive to the power levels of the signals and pumps. The results show that a reduction of the DRB noise by almost 2 to 3 orders can be reached. 相似文献
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Juanzi Shi HongXia Shen Lisheng Zhang Peijie Wang Yan Fang Guozhen Wu 《Journal of Raman spectroscopy : JRS》2015,46(12):1303-1309
An algorithm is employed to retrieve the differential bond polarizabilities (DBP) of the C‐C bonds from the Raman optical activity spectrum of (‐)β‐pinene. (‐)β‐pinene possesses two stereo centers (chiral centers) and a local mirror reflection that interchanges the S type part and R type part in one molecular. It is demonstrated that this local mirror reflection could induce an approximate (or symmetry breaking) mirror reflection that reverses the signs of the DBP of the pair bond coordinates that are related to each other by the mirror reflection.This can be called intramolecular enantiomerism (IE). More cases of IE are discussed by the analysis of (‐)α‐pinene, (R)‐(+)‐4‐isopropyl‐1‐methylcyclohexene and (R)‐(+)‐3‐methylcyclohexanone together with previously studied limonene case. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Raman optical activity (ROA) has been exclusively observed in the visible (VIS) and near‐infrared (NIR) spectral regions to date. During the last few years, we have designed, constructed and tested the first ROA instrument, operating in the deep‐ultraviolet (DUV) spectral region employing 244‐nm excitation. This novel DUV ROA instrument is based on a backscattering geometry and incident circular polarization modulation (ICP); it makes use of a fast DUV imaging lens‐based spectrograph and specially designed DUV grade polarization optics. The performance of this instrument has been evaluated by analysing measured non‐resonant DUV ROA spectra of non‐absorbing enantiomeric liquid samples and by comparing these with corresponding ROA spectra recorded in the visible spectral region. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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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
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Christian Merten Honggang Li Xuefang Lu Andreas Hartwig Laurence A. Nafie 《Journal of Raman spectroscopy : JRS》2010,41(12):1563-1565
Natural resonance electronic Raman optical activity (ROA) is observed for the first time. Coincidently, the first example of vibrational ROA enhanced by low‐lying electronic transition is reported. These new phenomena were measured using the rare‐earth complex Eu(tfc)3 (+)‐tris[3‐trifluoroacetyl‐D ‐camphorato]europium(III), where electronic resonance occurs between the 532‐nm laser excitation and the 7F1 → 5D1 transition of the Eu3+ metal center. Electronic Raman spectra involve the Raman transitions terminating on the low‐lying electronic states of Eu(tfc)3. The observed vibrational ROA spectra are enhanced relative to typical ROA spectra by the proximity of vibrational states of Eu(tfc)3 to its low‐lying electronic states with significant magnetic‐dipole character, whereas the parent vibrational Raman spectra do not appear to be resonance‐enhanced since the 532‐nm vibrational Raman spectrum has similar relative intensities to the corresponding Raman spectrum measured with 1064‐nm laser excitation. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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在单模光纤中放大的反斯托克斯拉曼背向自发散射的温度效应 总被引：8，自引：0，他引：8
在单模光纤中,输入的激光功率大于阈值时．出现放大的反斯托克斯拉曼背向自发散射现象。实验发现：放大的反斯托克斯拉曼背向自发散射具有温度效应．与反斯托克斯拉曼背向自发散射一样,放大的拉曼散射光的光子通量受到光纤温度的调制。反斯托克斯拉曼背向白发散射的放大效应抑制了单模光纤中的相干噪声,改善了系统的信噪比。实验还发现．放大的反斯托克斯扎曼背向自发散射空域曲线上放大的端点位置随激发功率的增高前移并具有一定的规律性。放大的反斯托克斯拉曼背向自发散射的温度效应作为一种新的测温原理,已应用于远程30km分布光纤温度传感器系统。 相似文献
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We calculated the polarized Raman spectra (PRS) and angle-resolved polarized Raman intensities (APRIs) of graphene nanoribbons with edges terminated by functional groups C=O and C-O-C, respectively, based on first-principles calculations. The exist results of the hydrogen saturated edges are recalculated for comparison. Our results show that the edge structures could be efficiently identified by the PRS and APRI. The APRI can also identify the orientation of the graphene nanoribbons. 相似文献
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Investigation of Near-Field Imaging Characteristics of Radial Polarization for Application to Optical Data Storage 总被引：4，自引：0，他引：4
Wan-Chin Kim No-Cheol Park Yong-Joong Yoon Hyun Choi Young-Pil Park 《Optical Review》2007,14(4):236-242
Radially polarized incident light can generate a more confined longitudinal electric field on a focal plane in near-field
(NF) optics than focusing circularly polarized light. Using this phenomenon, it is feasible to reduce beam spot size on storage
media to increase the areal density of optical data storage. A radially polarized beam generates a beam spot which is 20%
more confined on the 1st surface of medium than that of circularly polarized light. However, the peak intensity of total electric
field sharply decreases and its transverse component is much more dominant inside the media stack. This confirms that radially
polarized optics can be a candidate not for an NF recording system but for an NF read-only memory (ROM) system. Potentially,
the results could be useful to understand the effect of radial and circular polarizations inside and outside medium for various
applications of NF optics. 相似文献
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Rayleigh backscattering (RB) is an intrinsic phenomenon when light propagating in fiber and its level is fixed by the fiber type and the network configuration used. Thus, RB noise would be one of the major impairments in a carrier distributed passive optical network (PON). Previously demonstrated carrier suppressed subcarrier-amplitude modulated phase shift keying (CSS-AMPSK) modulation may be useful to effectively mitigate the RB noise. However, this modulation is basically a carrier suppressed double sidebands modulation (CS-DSB) format, in which the same information is carried by the two sidebands with equal magnitude. This is not very power-efficient for PON. Here, we further extend our RB studies by using carrier suppressed single sideband non-return-to-zero (CS-SSB-NRZ) modulation. We experimentally characterize the CS-SSB-NRZ modulation when subjected to both contributions of RB: Carrier-RB and Signal-RB. Then, numerical simulations are performed, and the results are in good match with the experiment. Finally, upstream transmission experiment is performed showing the feasibility of using the CS-SSB-NRZ signal for the carrier distributed PON. The RB performance of the SSB-NRZ signals transmitted at different distances and driven at different radio-frequency (RF) fs is also investigated. 相似文献
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Two substrate integrated waveguide (SIW) cavity antenna arrays based on metasurface are proposed in this paper. By rotating the metasurface element, circularly polarized and high gain antennas are achieved respectively. Firstly, multi-mode resonance theory is employed to broaden the bandwidth of the slot antenna. And then, an SIW cavity composed of 4×4 cornercut elements is added on the top of the slot antenna to achieve the circular polarization and improve the front-to-back ratio. Thirdly, the metasurface elements are sequentially rotated and a high gain antenna with 2-dBi enhancement on average in the operation band is obtained. Based on the two antenna units, two 2×2 antenna arrays are designed. The circularly polarized and high gain antenna arrays are both fabricated to verify the correctness. Furthermore, the novel wideband phase shifter is employed in the circularly polarized antenna to obtain an operating bandwidth of 38% (4.05 GHz-5.95 GHz) and AR bandwidth of 24.9% (4.4 GHz-5.65 GHz). The bandwidth of the high gain antenna can reach 42.7% (3.95 GHz-6.1 GHz) and with the gain enhancement of 2 dBi compared with that of the circularly polarized antenna. The gain remains steady in most of operating band within a variation of 1 dBi. It is remarkable that the rotating of the metasurface element has a great influence on the antenna performance, which provides a new explication for the multi-function antenna design. 相似文献
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