Tunable terahertz reflection spectrum based on zinc-blende structure crystals excited by ultrasonic

摘要

The tunable terahertz reflection spectrum of zinc-blende structure crystals (ZnSe, CuCl and InP), formed in the first bandgap, excited by ultrasonic is investigated in the present paper. Numerical simulation results show that, under the pressure of 0 GPa-100 GPa, the volume change of the crystal indicates that the zinc-blende structure crystals are suitable acousto-optic crystal. According to the optical phonon resonance dispersion, the frequency selective bandwidth of ZnSe, CuCl and InP crystal are 22.5 meV, 21.4 meV and 32.4 meV, respectively, indicating that the frequency selection range of InP crystal is wide. The transverse optical polariton is dis-propagating in the first bandgap and reflects. With the increase of ultrasonic frequency, the reflection peaks moves towards the restrahlen band, and the amplitude of the reflection spectrum decreases until it disappears. More transverse optical phonon combinations make the width of the reflection peak wider. The tunable terahertz reflection spectrum can be achieved by adjusting the ultrasonic frequency, a satisfactory condition for tunable selection and filtering in terahertz range.