Cavity optomechanics with a laser-engineered optical trap

Lasers are used to engineer effective potentials for photons and polaritons in semiconductor microcavities. Here, the authors show that vibrations can be cooled down in three-dimensional optical traps molded, tuned, and pumped with light. A photoelastic optomechanical coupling of ${g}_{0}$/2$\ensuremath{\pi}$ ~ 1.8 MHz is demonstrated in GaAs quantum well embedded resonators, attaining an optomechanical cooperativity $C$ > 1 for milliwatt excitation. This allows the cooling of mechanical vibrations by more than 160 K from room temperature, with record frequencies as high as ~180 GHz.