Design of dispersive optomechanical coupling and cooling in ultrahigh-Q/V slot-type photonic crystal cavities

TL;DR

This paper explores the design of ultrahigh-Q/V slot-type photonic crystal cavities that exhibit strong dispersive optomechanical coupling and demonstrate potential for cooling and amplification through dynamical interactions.

Contribution

It introduces a novel slot-type photonic crystal cavity design with high Q and small modal volume, enabling strong dispersive coupling and dynamical optomechanical effects.

Findings

Dispersive coupling up to 940 GHz/nm was numerically achieved.

Optomechanical dynamical effects like cooling and amplification were analyzed.

Cavity Q up to 5 million with a mechanical resonance at 460 MHz.

Abstract

We describe the strong optomechanical dynamical interactions in ultrahigh-Q/V slot-type photonic crystal cavities. The dispersive coupling is based on a mode-gap photonic crystal cavities with light localization in an air mode with 0.02(lambda/n)3 modal volumes while preserving optical cavity Q up to 5 x 106. The mechanical mode is modeled to have fundamental resonance omega_m/2pi of 460 MHz and a quality factor Qm estimated at 12,000. For this slot-type optomechanical cavity, the dispersive coupling gom is numerically computed at up to 940 GHz/nm (Lom of 202 nm) for the fundamental optomechanical mode. Dynamical parametric oscillations for both cooling and amplification, in the resolved and unresolved sideband limit, are examined numerically, along with the displacement spectral density and cooling rates for the various operating parameters.