Nonlinear interaction and coherent phonon dynamics in electromechanical resonators

The periodic elastic motion of mechanical elements can be regarded as an ensemble of acoustic phonons, described as a phonon coherent state in quantum mechanics. An electromechanical resonator is one of the most ideal phonon cavities, where the phonon ensemble survives much longer than the oscillation period. The long-lived phonons at different normal modes have larger probability for mutual interaction and the precise manipulation of mechanical oscillation through the nonlinear dynamics becomes possible. GaAs/AlGaAs parametric resonators allow us to electrically control the nonlinear coupling of different mechanical modes and provide an excellent platform for the experiments of nonlinear phononics. In this talk, I will present our approaches on the nonlinear phononics experiments using the semiconductor-based electromechanical resonators.
 Starting from the basic mechanism of nonlinear interaction in our devices, the concepts of single/multi-mode and red/blue-sideband parametric amplification will be described. As the examples of their implementation, I will review our recent results on the coherent control [1], phonon lasing [2], dynamic control in a phononic crystal waveguide [3], and 2-mode thermal noise squeezing [4]. The highly controllable mechanical devices open up a new direction in the study of the fundamental phonon dynamics, as well as the realization of novel kind of electromechanical systems, including high-speed sensors and actuators, high-frequency filters, and ultra-high energy-efficient phonon processors.

References

[1]	H. Okamoto, A. Gourgout, C.-Y. Chang, K. Onomitsu, I. Mahboob, E. Y. Chang, and H.
Yamaguchi, “Coherent phonon manipulation in coupled mechanical resonators” Nature Phys. 9, 481 (2013).
[2] 	I. Mahboob, K. Nishiguchi, A. Fujiwara, and H. Yamaguchi, “Phonon lasing in an electromechanical resonator” Phys. Rev. Lett. 110, 127202 (2013).
[3] 	D. Hatanaka, I. Mahboob, K. Onomitsu, and H. Yamaguchi, “Phonon waveguides for electromechanical circuits” Nature Nanotech. 9, 520 (2014).
[4] 	I. Mahboob, H. Okamoto, K. Onomitsu, and H. Yamaguchi, “Two-mode squeezing in an electromechanical resonator” Phys. Rev. Lett. 113, 167203 (2014).