Momentum controlled optical pulse amplification in photonic time crystals

Abstract: We show that by manipulating the momentum (k) of a propagating optical pulse, the intensity can be controlled and highly enhanced in a linear binary photonic time crystal (PTC) system. The optical pulse equipped with k lying within the bandgap of the PTC gets amplified and gives rise to reflected and transmitted pulses with an equal growth in intensity moving in opposite directions. We predict and quantify the amount of amplification of the transmitted and reflected pulse and show the amplifications achieve a maximum at the centre of the k-gap accompanied by weaker growth in intensity at the edges. The maximum growth in the intensity of the optical pulses attains different values for different ranges of k-gaps in such systems. Such precise control over the amplification of propagating pulse can be exploited exclusively by tailoring the wave vector of the pulse and open a unique platform for light manipulation in futuristic unconventional active photonic devices.