In recent years, photon drag has attracted enormous attention owing to both fundamental and practical interests. In this paper, by presenting a density-matrix approach, we have theoretically demonstrated an enhanced photon drag in a moving atomic medium. By incorporating of the interference of spontaneous emission, properties of the medium can be easily controlled by the relative phase of applied fields so that a large group index along with a transparency or even a gain can be achieved. As photon drag is proportional to group index, the enhancement can be also found in the dragging effect. Applications of the enhanced dragging effect can be found for efficient modulators of light, position control, and detection of slow motion.
Fizeau experiment, inspiring Einstein's special theory of relativity, reveals a small dragging effect of light inside a moving medium. Dispersion can enhance such light drag according to Lorentz's predication. Here we experimentally demonstrate slow and fast light enhanced light drag in a moving optical microcavity through stimulated Brillouin scattering induced transparency and absorption. The strong dispersion provides an enhancement factor up to ~10^4, greatly reducing the system size down to the micrometer range. These results may offer a unique platform for a compact, integrated solution …
The observations reported by Franke-Arnold et al (SCIENCE Reports, 1 July 2011 p. 65) do not provide evidence of slow light enhanced rotary photon drag as claimed, but arise from well-known saturable absorption phenomena consistent with the use of a spectrally broad light source, as described in their theoretical analysis (supporting online material)
We presented a new way to examine the principle of relativity of Special Relativity. According to the principle of relativity, the light dragging by moving media and the light propagation in stationary media with moving source and receiver should be two totally equivalent phenomena. We select a vacuum tube with two glass rods at two ends as the optical media. The length of the middle vacuum cell is L and the thicknesses of the glass rods with refractive index n are D1 and D2. The light drag effect of the moving vacuum tube with speed v is a first-order effect, delta t = 2(n-1)(D1+D2)v/c^2, whi…
We present a new derivation of the Fresnel-Fizeau formula for the drag of light by a moving medium using a simple perturbation approach. We focus particulary on the physical origin of the phenomenon and we show that it is very similar to the Doppler-Fizeau effect. We prove that this effect is, in its essential part, independent of the theory of relativity. The possibility of applications in other domains of physics is considered.
The Fresnel-Fizeau effect of transverse drag, in which the trajectory of a light beam changes due to transverse motion of the optical medium, is usually extremely small and hard to detect. We observe transverse drag in a moving hot-vapor cell, utilizing slow light due to electromagnetically induced transparency (EIT). The drag effect is enhanced by a factor 360,000, corresponding to the ratio between the light speed in vacuum and the group velocity under EIT conditions. We study the contribution of the thermal atomic motion, which is much faster than the mean medium velocity, and identify the …
The propagation of light in moving media is dragged by atomic motion. The light-drag effect can be dramatically enhanced by reducing the group velocity with electro-magnetically induced transparency (EIT). We develop a systematic procedure to accurately reconstruct the complex wavefront of the slow light with single-shot measurements, enabling precise, photon shot-noise limited spectroscopic measurements of atomic response across EIT even in presence of generic atomic number fluctuations. Applying the technique to an expanding cloud of cold atoms, we demonstrate simultaneous inference of the a…
A moving medium drags light along with it as measured by Fizeau and explained by Einstein's theory of special relativity. Here we show that the same effect can be obtained in a situation where there is no physical motion of the medium. Modulations of both the permittivity and permeability, phased in space and time in the form of travelling waves, are the basis of our model. Space-time metamaterials are represented by effective bianisotropic parameters, which can in turn be mapped to a moving homogeneous medium. Hence these metamaterials mimic a relativistic effect without the need for any actu…
We study the mobility of small-amplitude solitons attached to moving defects which drag the solitons across a two-dimensional (2D) discrete nonlinear-Schrödinger (DNLS) lattice. Findings are compared to the situation when a free small-amplitude 2D discrete soliton is kicked in the uniform lattice. In agreement with previously known results, after a period of transient motion the free soliton transforms into a localized mode pinned by the Peierls-Nabarro potential, irrespective of the initial velocity. However, the soliton attached to the moving defect can be dragged over an indefinitely long d…
A moving dielectric medium can displace the optical path of light passing through it, a phenomenon known as the Fresnel-Fizeau optical drag effect. The resulting displacement is proportional to the medium's velocity. In this article, we report on an anomalous optical drag effect, where the displacement is still proportional to the medium's speed but along the direction opposite to the medium's movement. We conduct an optical drag experiment under conditions of electromagnetically-induced transparency and observe the transition from normal, to null, to anomalous optical drag by modification of …
We review the theory of light propagation in moving media with extremely low group velocity. We intend to clarify the most elementary features of monochromatic slow light in a moving medium and, whenever possible, to give an instructive simplified picture.
Fizeau demonstrated in 1850 that the speed of light can be modified when it is propagating in moving media. Can we achieve such control of the light speed efficiently with a fast-moving electron media by passing electrical current? Because the strong electromagnetic coupling between the electron and light leads to the collective excitation of plasmon polaritons, it will manifest as the plasmonic Doppler effect. Experimental observation of the plasmonic Doppler effect in electronic system has been challenge because the plasmon propagation speed is much faster than the electron drift velocity in…
Experiments on light dragging in a moving medium laid the cornerstones of modern physics more than a century ago, and they still are in the focus of current research. When linearly polarized light is transmitted through a rotating dielectric, the polarization plane is slightly rotated -- a phenomenon first studied by Fermi in 1923. For typical non-resonant dielectric materials, the measured polarization drag angle does not surpass several microradians. Here we show that this effect may be dramatically enhanced if the light is sent to a gas of fast unidirectionally spinning molecular superrotor…
