Beam deflection and negative drag in a moving nonlinear medium

Abstract

Light propagating in a moving medium with refractive index other than unity is subject to light drag. While the light drag effect due to the linear refractive index is often negligibly small, it can be enhanced in materials with a large group index. Here we show that the nonlinear refractive index can also play a crucial role in propagation of light in moving media and results in a beam deflection that might be confused with the transverse drag effect. We perform an experiment with a rotating ruby crystal which exhibits a very large negative group index and a positive nonlinear refractive index. The negative group index drags the light opposite to the motion of the medium. However, the positive nonlinear refractive index deflects the beam towards the motion of the medium and hinders the observation of the negative drag effect. Hence, we show that it is necessary to measure not only the transverse shift of the beam, but also its output angle to discriminate the light-drag effect from beam deflection -- a crucial step missing in earlier experiments.

arXiv comment13 pages, 13 figures

References in corpus (12)

• Ultrasensitive Beam Deflection Measurement via Interferometric Weak Value Amplification
• What is Nonreciprocity?
• Photonics of Time-Varying Media
• Relativistic Effects of Light in Moving Media with Extremely Low Group Velocity
• Spatial solitons and modulational instability in the presence of large birefringence: the case of highly non-local liquid crystal
• Transverse Fresnel-Fizeau drag effects in strongly dispersive media
• On the dragging of light by a rotating medium
• Observation of light dragging in rubidium vapor cell
• Optical Spatial Shock Waves in Nonlocal Nonlinear Media
• Slow light in moving media
• Phase-controlled photon drag in a slow-light moving medium
• Strong Reverse Saturation and Fast-Light in Ruby