Université de Toulouse, UPS, Laboratoire Collisions Agrégats Réactivité, IRSAMC, F-31062 Toulouse, France.
Phys Rev Lett. 2011 May 13;106(19):193003. doi: 10.1103/PhysRevLett.106.193003. Epub 2011 May 11.
We report the direct observation of the nonreciprocity of the velocity of light, induced by electric and magnetic fields. This bilinear magneto-electro-optical effect appears in crossed electric and magnetic fields perpendicular to the light wave vector, as a refractive index difference between two counterpropagating directions. Using a high finesse ring cavity, we have measured this magnetoelectric nonreciprocity in molecular nitrogen at ambient temperature and atmospheric pressure; for light polarized parallel to the magnetic field it is 2η(∥exp)(N2) = (4.7±1)×10(-23) m V(-1) T(-1) for λ = 1064 nm, in agreement with the expected order of magnitude. Our measurement opens the way to a deeper insight into light-matter interaction beyond the electric dipole approximation. We were able to measure a nonreciprocity as small as Δn =(5±2)×10(-18), which makes its observation in quantum vacuum a conceivable challenge.
我们报告了由电场和磁场引起的光速的非互易性的直接观测。这种双线性磁光电光效应出现在垂直于光波矢的交叉电场和磁场中，表现为两个相反传播方向之间的折射率差。我们使用高精细度环形腔，在环境温度和大气压下测量了分子氮中的这种磁电非互易性；对于与磁场平行偏振的光，在 λ = 1064nm 时，它为 2η(∥exp)(N2) = (4.7±1)×10(-23) m V(-1) T(-1)，与预期的数量级一致。我们的测量为深入了解超越电偶极近似的光物质相互作用开辟了道路。我们能够测量到非常小的非互易性 Δn =(5±2)×10(-18)，这使得在量子真空中观察它成为一个可以想象的挑战。
