Magneto-optical control of the speed of light

Luke Horstman, Curtis Graber, Seth Erickson +2 more

Yu. M. Golubev, T. Yu. Golubeva, Yuri V. Rostovtsev +1 more

Paul S. Hsu, Sukesh Roy, James R. Gord +1 more

We investigate the use of a magnetic field, in conjunction with an elliptically polarized laser field, to control the group velocity of light in an inhomogeneously broadened medium. We show both theoretically and experimentally that the dispersion and hence, the speed of light in an atomic system, having V-configuration with Zeeman sublevels as their excited states, can be effectively controlled magneto-optically. We present approximate analytical solutions for a homogeneously broadened medium and numerical solutions for both a homogeneously and an inhomogeneously broadened medium. We show that while one can tune the speed of light from subluminal to superluminal with the magnetic field in a static or cooled medium with V-type atoms, in hot atoms one can achieve an efficient magneto-optical tunability in the subluminal regime. We experimentally demonstrate such control of light speed using a single elliptically polarized light and a moderately strong magnetic field in a 87Rb vapor cell. We propose to use the optical field for coarse control and the magnetic field for finer control of the light speed in an atomic medium.

Anil K. Patnaik, G. S. Agarwal

Liyun Zhang, Yang Yang, Xin Yang +2 more

Abstract The ultimate challenge for shaping technology is how to control the light field with a single optical element in a high-speed manner, wherein the spatial distribution of amplitude, phase or polarization are manipulated. Here we describe the use of the magneto optic effect to achieve the rapidly shaping of vector beams in real time using atomic ensemble. Firstly, the Faraday-rotation effect of vector beams is shown. On this basis, dynamically modulate the polarization of a vector beams on each point is implemented, and the polarization state of the manipulated beam is characterized with spatially resolved Stokes parameters measurements. The response time of this manipulation is about 40 μ s. The magnetic field high-speed switching and the dynamic manipulation capabilities of this method will be particularly useful for controlling light propagation through complex media and speed up the measurement of the properties of media.

Yanting Zhao, Jie Ma, Xianli Zhang +3 more

Absorption spectra of cold cesium atoms confined in a magneto-optical trap are observed around the D2 transition line (6S(1/2), F=4-->6P(3/2), F'=5) with the probe laser frequency detuned near the trapping laser frequency. We observe the dispersion-like profile resulted from the stimulated Raman processes with the sub-natural linewidth, and study the behavior of the group velocity of light in trapped cold atoms. By only changing the blue and red detuning of the probe frequency from the trapping laser frequency, we are able to arbitrarily control the speed of a light pulse from subluminal to superluminal velocity.