Issue
EPL
Volume 82, Number 6, June 2008
Article Number 60002
Number of page(s) 4
Section General
DOI http://dx.doi.org/10.1209/0295-5075/82/60002
Published online 29 May 2008
EPL, 82 (2008) 60002
DOI: 10.1209/0295-5075/82/60002

Deflection of ultra-slow light by the Earth's gravity on laboratory length scale

N. Kumar

Raman Research Institute - Bangalore 560080, India

nkumar@rri.res.in

received 26 February 2008; accepted in final form 22 April 2008; published June 2008
published online 29 May 2008

Abstract
The high speed of light in vacuo together with the weakness of Earth's gravity rule out any experimental detection of gravitational deflection of light on the laboratory length scale. Recent advances in coherent nonlinear optics that produce ultra-slow light in highly dispersive media with group velocities down to $\sim\kern-2pt$ 102 ms-1, or even less, however, open up this possibility. In this work, we present a theoretical study for a possible laboratory observation of the deflection of such an ultra slow light in the highly dispersive medium under the Earth's gravity. Our general relativistic calculation is based on the Gordon optical metric modified so as to include dispersion. The calculated linear vertical deflection turns out to be ~ 0.1 mm for a horizontal traversal of 0.5 m and a group speed vg ~ 102 ms-1. Experimental realizability and some conceptual points involved will be briefly discussed.

PACS
04.20.-q - Classical general relativity.
95.30.Sf - Relativity and gravitation.
42.50.Gy - Effects of atomic coherence on propagation, absorption, and amplification of light; electromagnetically induced transparency and absorption.

© EPLA 2008