Abstract
Sound amplification in an electrically biased superlattice (SL) is studied in optical experiments with 100fs time resolution. Coherent SL phonons with frequencies of 40, 375, and 410GHz give rise to oscillatory reflectivity changes. With currents from 0.5 to 1.3A, the Fourier amplitude of the 410GHz phonon increases by more than a factor of 2 over a 200ps period. This amplification is due to stimulated Čerenkov phonon emission by electrons undergoing intraminiband transport. The gain coefficient of 8×10^{3} cm^{-1} is reproduced by theoretical calculations and holds potential for novel sub-THz phonon emitters.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.