Abstract

Field–sensitive nonlinear phenomena in semiconductors beyond the conventional perturbation theory have been investigated recently using extremely intense terahertz pulses. This year spring, we reported the anomalous luminescence under the irradiation of the THz free electron laser (THz-FEL) pulses^[1]. The results, strong excitation frequency- and power-dependences of the luminescence from ZnO nanoparticles and surrounding nitrogen molecules, reflected the kinetic energy and trajectory of electrons outside the nanoparticles, which provided a new excitation path. However, one THz-FEL macropulse consists of about 100 FEL micropulses separated at 37 ns intervals (27 MHz repetition), which complicates the luminescence via undesired charge build-up on the nanoparticles.

© 2017 Japan Society of Applied Physics, Optical Society of America