Maxwell equation simulations of coherent optical photon emission from shock waves in crystals

We have predicted that weak coherent radiation in the 1-100 THz frequency regime can be emitted under some circumstances when a shock wave propagates through a polarizable crystal, like NaCl [Reed, Phys. Rev. Lett. 96, 013904 (2006)]. In this work, we present and analyze a new model of a shocked polarizable crystal that is amenable to systematic analytical study and direct numerical solution of Maxwell's equations to predict emitted coherent field amplitudes and properties. Our simulations and analysis indicate that the field amplitude of the effect decreases rapidly with increasing shock front rise distance. These models establish a fundamental limit of the ratio of emitted terahertz amplitude to the static polarization of a material. While this effect is treated classically in our previous work, we present a quantum perturbation analysis showing that it can also occur in the low-amplitude emission quantum limit.