Fig. 1. (a) The top view schematic of the nonsuspended As2S3 optomechanical crystal cavity. (b) A unit cell of the optomechanical crystal in the mirror region.

Fig. 2. (a) Optical band structure of the unit cell in the mirror region. (b) Acoustic band structure of the unit cell in the mirror region. (c) Electric field component Ey of the optical defect mode at the X point. Left: distribution of Ey at plane x=d1/2. Right: distribution of Ey at plane z=0. [The coordinate of the cavity center is set as (0,0,0).] (d) Displacement field component ux of the acoustic defect mode at the X point. Left: distribution of ux at plane x=d1/2. Right: distribution of ux at plane z=0.

Fig. 3. (a) Displacement field profile (ux) of a confined acoustic Bloch mode at the Γ point. (b) 2D FT spectrum of ux of the acoustic Bloch mode at the cavity interface perpendicular to the z direction (left) and interface perpendicular to the y direction (right). (c) Electric field profile (Ey) of a confined optical Bloch mode at the Γ point. (d) 2D FT spectrum of Ey of the optical Bloch mode at the cavity interface perpendicular to the z direction (left) and interface perpendicular to the y direction (right). (e) Electric field component Ey of the optical defect mode at the Γ point. Left: distribution of Ey at plane x=d1/4. Right: distribution of Ey at plane z=0. (f) Displacement field component ux of the acoustic defect mode at the Γ point. Left: distribution of ux at plane x=d1/4. Right: distribution of ux at plane z=0. (g) 2D FT spectrum of Ey of the optical defect mode at the cavity interface perpendicular to the y direction (left). 2D FT spectrum of ux of the acoustic defect mode at the cavity interface perpendicular to the y direction (right).

Fig. 4. (a) A dual-cavity system of nonsuspended As2S3 optomechanical crystal cavities with a separation distance L. (b) Profiles of the calculated supermodes in the dual-cavity system. Top: the odd mode. Bottom: the even mode. (c) Left ordinate: calculated acoustic coupling rates between two identical cavities (black solid line) and between two different cavities with the same acoustic frequency (black dashed line). Right ordinate: optical coupling rates between two identical cavities (red solid line) and between two different cavities with the same acoustic frequency (red dashed line).