Giant phase modulation in a Mach-Zehnder exciton-polariton interferometer

摘要

We report on a new mechanism of giant phase modulation. The phenomenon ariseswhen a dispersed photonic mode (slow light) strongly couples to an excitonicresonance. In such a case, even a small amount of optically injected carrierscreates a potential barrier for the propagating exciton-polariton whichprovokes a considerable phase shift. We evidence this effect by fabricating anexciton-polariton Mach-Zehnder interferometer, modulating the output intensityby constructive or destructive interferences controlled by optical pumping of amicrometric size area. The figure of merit for a {\pi} phase shift, defined bythe control power times length of the modulated region, is found at least oneorder of magnitude smaller than slow light photonic crystal waveguides.