THz Acoustic Attenuations of Glycerol by Pump Probe Technique

TL;DR

This study measures THz acoustic attenuation in glycerol using pump probe technique, comparing results with scattering methods, revealing temperature-dependent attenuation increases up to 0.5 THz.

Contribution

It introduces a femto-sec laser pump probe method to measure glycerol's THz acoustic attenuation and compares it with established scattering techniques.

Findings

Attenuation increases with frequency up to 0.5 THz.

Results match within 0.5 THz with inelastic neutron and X-ray scattering.

Attenuation is higher at room temperature (295 K) than at 120 K.

Abstract

The coherent acoustic waves can be created by InGaN double quantum wells. We measured the signals information of the coherent acoustic waves at the interface of GaN/glycerol to obtain the attenuations of glycerol at 295 K and 120 K by the femto-sec laser pump probe technique in THz regime. The attenuations of glycerol are calculated by using the acoustic mismatch model (AMM) through the complex acoustic impedance. We compared pump probe results with inelastic neutron scattering (INS) and inelastic X ray scattering (IXS), found they are matched within 0.5 THz at room temperature. The glycerol attenuations are found increasing monotonically to 1.75x10^8 m^(-1) and 1.3x10^8 m^(-1) till 0.5 THz by the pump probe technique at 295 K and 120 K, respectively.