共查询到20条相似文献,搜索用时 31 毫秒
1.
在铯原子气室中采用偏振方向相互垂直且同向传播的线偏泵浦光和探测光,研究了铯原子D2线的泵浦探测光谱。由于在6 S1/2 F=3 – 6 P3/2 F’=2 超精细跃迁中存在多个L型塞曼子能级结构,从而产生了电磁诱导透明导致的吸收减弱;而在6 S1/2 F=4 – 6 P3/2 F’=5 超精细跃迁中则观测到了电磁诱导吸收。通过改变泵浦光的失谐量,在电磁诱导透明形成的吸收减弱凹陷和电磁诱导吸收产生的吸收增强峰内部均观察到了反常的吸收信号反转。 相似文献
2.
Pump-probe differencing technique for cavity-enhanced, noise-canceling saturation laser spectroscopy
We present an experimental technique that permits mechanical-noise-free, cavity-enhanced frequency measurements of an atomic transition and its hyperfine structure. We employ the 532-nm frequency-doubled output from a Nd:YAG laser and an iodine vapor cell. The cell is placed in a folded ring cavity (FRC) with counterpropagating pump and probe beams. The FRC is locked with the Pound-Drever-Hall technique. Mechanical noise is rejected by differencing the pump and probe signals. In addition, this differenced error signal provides a sensitive measure of differential nonlinearity within the FRC. 相似文献
3.
《中国光学快报(英文版)》2015,(7)
We experimentally observe polarization spectroscopy(PS) of the 1S0-3P1 transition of mercury atom gases at 253.7 nm. The PS signal can be observed in all six richly abundant isotopes and the PS signal of six transitions for laser cooling are all clear and of a dispersive line shape. The optimized pump power and probe power are found for the PS of 202 Hg. We find the linearly polarized component in the pump beam will distort the original PS signal due to the use of linear PS. Consequently, the purity of the pump beam is crucial to laser frequency stabilization by PS. 相似文献
4.
We demonstrate two techniques for studying the features of three-level systems driven by two lasers (called control and probe), when the transitions are Doppler broadened as in room-temperature vapor. For
-type systems, the probe laser is split to produce a counter-propagating pump beam that saturates the transition for the zero-velocity atoms. Probe transmission then shows Doppler-free peaks which can even have sub-natural linewidth. For V-type systems, the transmission of the control beam is detected as the probe laser is scanned. The signal shows Doppler-free peaks when the probe laser is resonant with transitions for the zero-velocity group. Both techniques greatly simplify the study of three-level systems since theoretical predictions can be directly compared without complications from Doppler broadening and the presence of multiple hyperfine levels in the spectrum.Received: 10 September 2003, Published online: 6 January 2004PACS:
42.50.Gy Effects of atomic coherence on propagation, absorption, and amplification of light; electromagnetically induced transparency and absorption - 42.50.-p Quantum optics 相似文献
5.
We demonstrate polarization spectroscopy of an excited state transition in room-temperature cesium vapor. An anisotropy induced by a circularly polarized pump beam on the D2 transition is observed using a weak probe on the 6P(3/2)→7S(1/2) transition. At high pump power, a subfeature due to Autler-Townes splitting is observed that theoretical modeling shows is enhanced by Doppler averaging. Polarization spectroscopy provides a simple modulation-free signal suitable for laser frequency stabilization to excited state transitions. 相似文献
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7.
We have developed a high-spectral-resolution laser system for two-photon pump, polarization spectroscopy probe (TPP-PSP) measurements of atomic hydrogen in flames. In the TPP-PSP technique, a 243-nm laser beam excites the two-photon 1S-2S transition, and excited n=2 atoms are then detected by polarization spectroscopy of the n=2 to n=3 transition using 656-nm laser radiation. The single-frequency-mode 243 and 656-nm beams are produced using injection-seeded optical parametric generators coupled with pulsed dye amplifiers. The use of single-mode lasers allows accurate measurement of signal line shapes and intensities even with significant pulse-to-pulse fluctuations in pulse energies. Use of single-mode lasers and introduction of a scheme to select nearly constant laser energies enable repeatable extraction of important spectral features in atomic hydrogen transitions. 相似文献
8.
在一个具有超精细结构的四能级原子系统中,为了压抑暂态过程和稳态过程两种情况下的弱探测光束的吸收,我们提出和分析了一种有效的拉曼散射计划。对于暂态过程,借助一个漂亮的Mathematic程序进行数值计算,我们发现在探测跃迁线中心探测吸收的幅度与一般的基于电磁感应透明的三能级原子系统相比要小。对于稳态情况,结果表明探测吸收在线中心能够被彻底地消除,正像通常的三能级电磁感应透明方案。特别地,我们的结果表明在拉曼共振的条件下探测吸收能够被彻底地消除,也就是说,对于稳态过程我们仅仅要求双光子失谐量在超精细二能级频率间隙内是零。与标准的三能级电磁感应透明方案相比,我们的四能级拉曼计划的优点之一是在拉曼共振条件下我们能观察到透明窗口,不需要严格地单光子和双光子失谐量为零。因此,原子超精细结构对于获取电磁感应透明不是一个障碍。 相似文献
9.
S. Chakrabarti B. Ray P. N. Ghosh 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(3):359-368
The effects of a strong control or pump laser, counter propagating
or copropagating with the probe beam, on the probe absorption spectra of
85Rb and 87Rb-D2 transitions have been investigated inside
a room temperature Rb vapour cell. In both cases a set of strong velocity
selective resonance dips are observed at different velocities. Their
movements across the Doppler broadened probe absorption profile have been
studied for different lock frequencies of the control laser. These spectra
are modified by optical pumping effects due to the presence of another
hyperfine component of the ground state. A repumping laser, from the dark
hyperfine component of the ground level transfers almost 75% of the atoms
from the dark state to the pump probe cycle hence reducing the optical
pumping effect. A numerical simulation is done to explain the observed
spectra. The effect of a control laser on the Lamb dip spectrum of the probe
laser has also been investigated. The control beam is used to improve the
strength of a weak hyperfine dip on the Doppler broadened probe spectrum.
The strength of the hyperfine dip increases by a factor of 3.2 in presence
of the control laser. The observed dips show that pump-probe spectroscopy
can be used as velocity selectors of atoms. 相似文献
10.
Cs-He混合蒸气中的辐射陷获效应和6P3/2能级有效辐射率的测量 总被引:1,自引:1,他引:0
测量了Cs-He混合蒸气中Cs(6P3/2)共振能级的有效辐射率,圆柱形样品池充入金属Cs和气压PHe为0~500Pa的He,样品池温度控制在330~370K之间,在池中产生1012~1013cm-3的Cs原子密度,使用单模半导体激光器(泵浦激光)将Cs原子激发至6P3/2态,另一调谐到6P3/2→8S1/2的单模激光束(检测激光)与泵浦束反平行通过样品池,并在池的直径方向平行移动,通过对检测激光束的吸收测定了激发态原子密度及其空间分布。由于辐射陷获存在,有效辐射率是自然辐射率与透射因子(发射的光子在探测区域内没有被吸收的平均概率,它与吸收截面及激发态原子密度和空间分布有关)的乘积。由6P3/2原子密度及其空间分布结合6P3/2←6S1/2跃迁线的碰撞增宽计算了透射因子,从而得到了不同He气压下,CsD2线的有效辐射率。从6P3/26→S1/2跃迁线强度I852的测量,得到的不同He气压下有效辐射率的比值与理论计算得到的比值相符。 相似文献
11.
Pixley NC Correll TL Pappas D Matveev OI Smith BW Winefordner JD 《Optics letters》2001,26(24):1946-1948
A cesium-based resonance fluorescence monochromator with a spectral resolution of 200 MHz and a tunable response over the D(2) absorption line of cesium (380 MHz) is described. The narrow spectral response is achieved through excitation of a monokinetic population of the 6(2)P(3/2)( degrees ) state by arrangement of the excitation lasers in either a copropagating or a counterpropagating orientation. The narrow spectral response of the detector allows for excitation of specific hyperfine components involved in the 6(2)P(3/2)( degrees ) (F=3-5) to 6(2)D(5/2) (F=2-6) transition (917.23 nm). The selectivity gained through resolving specific hyperfine transitions allows for a photon detector that is both spectrally tunable and narrow. We report the sub-Doppler linewidths achieved through various laser beam orientations. We also describe how these beam geometries can be applied to spectrally narrow and tunable image detection. 相似文献
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We report single-laser-shot one-dimensional thermometry in flames using femtosecond coherent anti-Stokes Raman scattering (fs-CARS) line imaging. Fs-CARS enables high-repetition-rate (1-10?kHz), nearly collision-free measurement of temperature and species concentration in reacting flows. Two high-power 800?nm beams are used as the pump and probe beams and a 983?nm beam is used as the Stokes beam for CARS signal generation from the N2Q-branch transitions at ~2330?cm(-1). The probe beam is frequency-chirped for single-laser-shot imaging. All three laser beams are formed into sheets and crossed in a line which forms the probe region. The resulting 1D line-CARS signal at ~675?nm is spatially and spectrally resolved and recorded as a two-dimensional (2D) image. Single-shot temperature measurements are demonstrated in flat-field flames up to temperatures exceeding 2000?K, demonstrating the potential of fs-CARS line imaging for high-repetition-rate thermometry in turbulent flames. Such measurements can provide valuable data to validate complex turbulent-combustion models as well as increase the understanding of the spatio-temporal instabilities in practical combustion devices such as modern gas-turbine combustors and augmentors. 相似文献
14.
The use of crossed beam 2-Step Degenerate Four-Wave Mixing (2S-DFWM) for decreasing pre- and post-filtering effects under optically thick conditions has been investigated. 2S-DFWM is a technique in which the DFWM process is performed between two excited states of which the lower one is populated by an ordinary laser excitation from a low lying, highly populated state. Experiments were performed on Au in an acetylene/air flame. We have shown that under conditions where ordinary (one-step) DFWM experiments are significantly affected by pre- and post-filtering effects (i.e., partly absorption of the pump, probe or signal beams prior to or after the interaction region) the 2S-DFWM technique can give virtually interference free signals. A variety of different laser beam and flame configurations have been investigated. It was found that the use of a crossed beam geometry, where the first step exciting laser is incident upon the interaction region perpendicular to the DFWM beams, completely eliminated severe pre- and post-filtering effects occurring for an ordinary single-step DFWM scheme in an optically thick medium. 相似文献
15.
We have investigated the two-dimensional (2D) atom localization via probe absorption in a coherently driven four-level atomic system by means of a radio-frequency field driving a hyperfine transition. It is found that the detecting probability and precision of 2D atom localization can be significantly improved via adjusting the system parameters. As a result, our scheme may be helpful in laser cooling or the atom nano-lithography via atom localization. 相似文献
16.
Nonlinear Faraday rotation with counter-propagating light beams was investigated in a rubidium vapor cell. Observations across all hyperfine and crossover resonances of the D2 line of 87Rb atoms were made. Additionally, rotation spectra as a function of pump and probe intensity, pump polarization and external magnetic field strength were studied.The investigations were performed in a regime where the pump beam power was sufficiently low relative to the probe power to avoid polarization rotation due to pump-induced anisotropy. Our results are analyzed in the context of Bennett structures and coherent optical processes. 相似文献
17.
Mangesh Bhattarai Vineet Bharti Vasant Natarajan Armen Sargsyan David Sarkisyan 《Physics letters. A》2019,383(1):91-96
We study the sign of resonances obtained in electromagnetically induced transparency (EIT). Resonances of both kinds—bright (corresponding to enhanced absorption) and dark (corresponding to reduced absorption)—are obtained when the frequency of a probe beam is scanned. The experimental results, presented earlier, use magnetic sublevels of a hyperfine transition in the D1 line of 87Rb along with a magnetic field of 27 G. The atoms are contained in a vapor cell at room temperature, and with anti-relaxation coating on the walls. A quantitative theoretical model, which reproduces the experimental results quite well, is presented for the first time. The model solves the density matrix of the sublevels involved, and uses two regions—one with both the light and magnetic field, and the second without light and just a magnetic field. This ability to have both bright and dark resonances promises applications in sub- and super-luminal propagation of light. 相似文献
18.
We report the pump-probe measurements of nonlinear refractive index changes in photochromic bacteriorhodopsin films. The photoinduced
absorption is caused by pump beam at 532 nm and the accompanying refractive index changes are studied using a probe beam at
633 nm. The proposed technique is based on a convenient and accurate determination of optical path difference using digital
interferometry-based local fringe shift. The results are presented for the wild-type as well as genetically modified D96N
variant of the bacteriorhodopsin.
相似文献
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20.
低He气压下Rb(5P3/2)激发态有效辐射率的计算与测量 总被引:1,自引:1,他引:0
计算和测量了Rb-He混合蒸气中Rb(5P3/2)共振能级的有效辐射率,使用单模半导体激光器(泵浦激光)将Rb原子激发至5P3/2态,另一调谐到5P3/2→7S1/2的单模激光束(检测激光)与泵浦束反平行通过样品池,并在池的直径方向平行移动,通过对检测激光束的吸收测定了激发态原子密度及其空间分布.由于辐射陷获存在,有效辐射率是自然辐射率与透射因子(发射的光子在探测区域内没有被吸收的平均概率,它与吸收截面及激发态原子密度和空间分布有关)的乘积.5P3/2原子密度及其空间分布结合5P3/2←5S1/2跃迁线的碰撞增宽计算了透射因子,从而得到了不同He气压下,Rb D2线的有效辐射率.从5P3/2→5S1/2跃迁线强度I780的测量,得到的不同He气压下有效辐射率的比值与理论计算得到的比值相符. 相似文献