  Optomechanical systems based on nanophotonics are advancing the field of
precision motion measurement, quantum control and nanomechanical sensing. In
this context III-V semiconductors offer original assets like the
heteroepitaxial growth of optimized metamaterials for photon/phonon
interactions. GaAs has already demonstrated high performances in optomechanics
but suffers from two photon absorption (TPA) at the telecom wavelength, which
can limit the cooperativity. Here, we investigate TPA-free III-V semiconductor
materials for optomechanics applications: GaAs lattice-matched In0:5Ga0:5P and
Al0:4Ga0:6As. We report on the fabrication and optical characterization of high
frequency (500-700 MHz) optomechanical disks made out of these two materials,
demonstrating high optical and mechanical Q in ambient conditions. Finally we
achieve operating these new devices as laser-sustained optomechanical
self-oscillators, and draw a first comparative study with existing GaAs
systems.
