Terahertz radiation by quantum interference of excitons in a one-dimensional Mott insulator

Abstract

Nearly monocyclic terahertz waves are used for investigating elementary excitations and for controlling electronic states in solids. They are usually generated via second-order optical nonlinearity by injecting a femtosecond laser pulse into a nonlinear optical crystal. In this framework, however, it is difficult to control phase and frequency of terahertz waves. Here, we show that in a one-dimensional Mott insulator of a nickel-bromine chain compound a terahertz wave is generated with high efficiency via strong electron modulations due to quantum interference between odd-parity and even-parity excitons produced by two-color femtosecond pulses. Using this method, one can control all of the phase, frequency, and amplitude of terahertz waves by adjusting the creation-time difference of two excitons with attosecond accuracy. This approach enables to evaluate the phase-relaxation time of excitons under strong electron correlations in Mott insulators. Moreover, phase- and frequency-controlled terahertz pulses are beneficial for coherent electronic-state controls with nearly monocyclic terahertz waves.

Far IR field generation by mixing of cosh-Gaussian and dark hollow Gaussian laser in encapsulated plasma

“…Zhang et al [14] reported the design of a highly efficient THz detector incorporating a Tamm cavity, which involves an embedded detector chip within a multilayer Si/air Distributed Bragg Reflector (DBR) for significant enhancement of the strength of the THz signal. Miyamoto et al [15] applied a different approach of utilizing a 1D Mott insulator of a nickelbromine chain compound, leveraging strong electron modulation resulting from quantum interference between even and odd parity excitations to make notable strides in the efficient generation of THz waves. These advancements collectively set up a rapidly evolving landscape of THz research, contributing valuable insights and innovations to the field.…”