Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)

Exploration of electromagnetically induced absorption with circular polarised lasers in a degenerate two-level system

L. Spani Molella, K. Dahl, R.-H. Rinkleff, K. Danzmann

Published Jun 1, 2007• 0 citations

Abstract

The authors presented the corresponding measurements obtained with a modified version of our heterodyne interferometer. The measurement were obtained in the 6s 2S1/2F=4 rarr 6p2P3/2F=5 transition of the caesium D2line. As it is the case for double linear polarisation the probe absorption signals showed electromagnetically induced absorption. However, the amplitude of the induced absorption peak over the broader regular absorption signal resulted much lower than the measured one for the double linear case. This may be due to the fact that in the double circular case no compact N subsystems can be easily built between the sublevels. The resulting spectra are therefore similar to those measured in open two-level systems.

DOI: 10.1109/cleoe-iqec.2007.4386862

Related papers

Electromagnetically induced transparency, electromagnetically induced absorption, and giant Kerr effect in closed degenerate two-level systems

L. Spani Molella, R.-H. Rinkleff, Gerrit Kühn +1 more

Spontaneous transfer of coherence has proven to be a good interpretative scheme for the explantation of the spectra of a probe laser probing a closed degenerate two-level systems. With its aid it was possible to give an explanation for the emergence of electromagnetically induced absorption and also to make predictions on the associated coupling laser spectra. Here we extend our work on the role of the coupling laser in electromagnetically induced absorption presenting new measurements of the probe and coupling laser absorption and dispersion spectra - taken in the D2 line of caesium - which reassert the importance of spontaneous transfer of coherence in the generation of electromagnetically induced absorption spectra. All measurements were performed with linearly polarised coupling and probe laser of orthogonal polarisation, acting on a perpendicularly propagating caesium atomic beam to minimise the Doppler broadening of the lines. For sake of completeness we compared the electromagnetically induced absorption spectra with electromagnetically induced transparency spectra obtained in another two-level system within the same line. The measured probe spectra were used to calculate the refractive index of caesium in the presence of electromagnetically induced transparency and absorption. On that basis we could calculate the effect of Kerr nonlinearities and measure nonlinear Kerr coefficients of the order of n2 ≈ 10-5 cm2/mW with absorption coefficients of the order of &agr; ≈ 0.1 cm-1.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEMar 2, 20071 citation

Observation of EIA in closed and open caesium atomic system

Jianming Zhao, Yanting Zhao, Huang Tao +2 more

We present an experimental study on electromagnetically induced absorption (EIA) in the closed transition of a degenerate two-level Cs atomic system. The coupling and probe lasers coupled with the transition 6S1/2F=4 → 6P3/2F'=5 of caesium atom. The signal of EIA was obtained and the frequency detuning and intensity effect of the pumping laser were experimentally investigated. The EIA signal in 6S1/2 F=4 → 6P3/2 F'=4 and 6S1/2 F=4 → 6P3/2 F'=3 open transitions was also obtained. As the repumping laser couples with the transition of 6S1/2 F=3 → 6P3/2 F'=4, the EIA signal is increased due to the hyperfine optical pumping.

Chinese PhysicsMar 16, 20053 citations

Experimental Evidence of Spontaneous Transfer of Coherence in a Driven Degenerate Two-level System under the Action of a Linearly or a Circularly Polarized Probe

L. Spani Molella, K. Dahl, R.-H. Rinkleff +1 more

Electromagnetically induced absorption (EIA) in a degenerate closed transition was measured under the action of a probe and a coupling laser of various polarizations giving rise to different possible N-systems or multi-level systems. While the probe shows EIA the coupling is mainly characterized by “absorption within transparency”. However, for certain lasers' intensity ranges, a switch between “absorption within transparency” and “transparency within transparency” in the coupling absorption spectra was measured for the first time.

Quantum-Atom Optics Downunder (QAO)Jan 1, 20070 citations

Experimental observation of pump–probe spectra of caesium D 2 line with a vapour cell

Yanhua Wang, Yang Hai-Jing, Tiancai Zhang +1 more

Pump?probe spectra of caesium D2 line are experimentally investigated in a Cs atomic vapour cell with co-propagating orthogonal linearly-polarized pump and probe laser beams. Absorption-reduction dips duo to electromagnetically induced transparency (EIT) in multi-?-type Zeeman sublevels of 6 S1/2 F=3?6 P3/2 F'=2 hyperfine transition and absorption-enhanced peaks due to electromagnetically induced absorption (EIA) in 6 S1/2 F=4?6 P3/2 F'=5 hyperfine transition are demonstrated. With detuned pump beam abnormal sign-reversed signals inside the EIT dip and the EIA peak are clearly observed.

Chinese PhysicsMay 3, 20052 citations

Electromagnetically Induced Transparency in Λ-Type Zeeman Sublevels of Cesium Atoms

Tiancai Zhang

Employing two lasers as the coupling and probe fields which have opposite circular polarization (σ + and σ -), electromagnetically induced transparency (EIT) in Λ-type Zeeman sublevels of cesium 6 2S 1/2F=3-6 2P 3/2F′=2 degenerate two-level system has been demonstrated via probe absorption spectra. The effect of the intensity and detuning of different coupling. Laser on EII was also investigated in experiments. Within the Doppler background, optical pumping among Zeeman sub-levels and the population of different Zeeman sub-levels can dominate the intensity of EIT effect. And the physical reason of the rugged spectra are presented qualitatively.

Chinese Journal of LasersJan 1, 20050 citations

Unravelling the Mechanisms of Electromagnetically Induced Absorption and Transparency in Open Degenerate Multilevel System: Effects of Neighboring Transitions

Zeeshan Ali Safdar Jadoon, Heung‐Ryoul Noh, Jin‐Tae Kim

Abstract Optical Bloch equations with and without neighboring hyperfine states near the degenerate two-level system (DTLS) in the challenging case of 85Rb D2 transition that involves the Doppler broadening effect are solved herein. The calculated spectra agree well with the experimental results obtained using the coupling-probe scheme with orthogonal linear polarizations of the coupling and probe fields. The mechanisms of electromagnetically induced absorption (electromagnetically induced transparency) for the open Fg = 3 → Fe = 2 and 3 transitions (open Fg = 2 → Fe = 2 and 3 transitions) are clearly determined to be the effect of the strong closed Fg = 3 → Fe = 4 transition line (strong closed Fg = 2 → Fe = 1 transition line) based on the comparisons of the calculated absorption profiles of a DTLS without neighboring states and those of all levels with neighboring states depending on the coupling and probe power ratios. The crucial factors established based on comparisons of the calculated absorption profiles of DTLS with and without neighboring states, which enhance or reduce coherence effects and result in transformation between electromagnetically induced absorption and electromagnetically induced transparency, are the power ratios between coupling and probe beams, openness of the excited state, and effects of the neighboring states due to the Doppler broadening in a real atomic system.

Jul 15, 20210 citations