Generation and detection of gigahertz acoustic oscillations in thin membranes

摘要: Single crystalline membranes are a perfect model system for the study of coherent acoustic phonon generation and decay in time domain. Coherent acoustical modes excited detected thin single-crystalline silicon gallium arsenide with femtosecond pulses ultraviolet infrared wavelength region using asynchronous optical sampling technique. The measured spectra compared each other discussed terms different detection mechanisms. A clear dependence generated on absorption length pump probe is observed. It shown that short pulse leads to high frequency phonons up several 100 GHz frequencies. Membranes demonstrated be useful as broadband cavities can help disentangle details dynamics. Two-layer membrane systems offer additional insight into energy transfer range adhesion properties.