We finally managed to fabricate high-Q trampoline micromechanical resonators in the crystalline material InGaP. Thanks to the hard work of Sushanth, Anastasiia and Fia and the material supplied by the group of André Strittmatter from Magdeburg. You find the results here on arXiv:2211.12469 [physics.app-ph].
The exciting journey continues towards fully integrated free-space cavity optomechanics on a chip.