Exploring regenerative coupling in phononic crystals for room temperature quantum optomechanics

Area of Science:

• Quantum Technologies
• Nanomechanics
• Materials Science

Background:

• Quantum technologies offer significant advantages over classical methods but are often limited by the need for extremely low temperatures.
• Radiative mechanical energy dissipation is a key challenge in nanomechanical oscillators, hindering their performance.
• Phononic crystals (PnCs) are engineered structures that control the propagation of mechanical vibrations.

Purpose of the Study:

• To develop a method for suppressing radiative mechanical energy dissipation in nanomechanical oscillators.
• To enable quantum technologies to operate effectively at room temperature.
• To enhance the performance of nanomechanical resonators through phononic bandgap engineering.

Main Methods:

• Utilizing Finite Element Method (FEM) for phononic bandgap engineering.
• Implementing regenerative coupling between a nanomechanical oscillator and a defect mode in a PnC.
• Applying the method to an optomechanically coupled nanobeam resonator in the megahertz regime.

Main Results:

• Achieved significant suppression of radiative mechanical energy dissipation.
• Demonstrated mechanical quality factor improvement of up to four orders of magnitude compared to conventional PnC designs.
• Reached f × Q products exceeding 10^16 Hz with only two rows of PnC shielding.

Conclusions:

• The regenerative coupling method is versatile and applicable to various resonator types and frequencies.
• Stable quantum states with mechanical decoherence times up to 700 μs at room temperature are achievable.
• This advancement opens new avenues for room-temperature quantum applications and resonator optimization.