Ultra-dispersive adaptive prism

We have experimentally demonstrated an ultra-dispersive optical prism made from coherently driven Rb atomic vapor. The prism possesses spectral angular dispersion that is six orders of magnitude higher than that of a prism made of optical glass; it is the highest spectral angular dispersion that has ever been shown (such angular dispersion allows one to spatially resolve light beams with different frequencies separated by a few kHz). The prism operates near the resonant frequency of atomic vapor and its dispersion is optically controlled by a coherent driving field.