There are various technological challenges, but all are within high-end laboratory capabilities. The primary requirement is that the mass of the cavity remains as small as possible. To avoid noise on the interferometer and have a low probability of emitting more than one photon each time, a very low absolute temperature for the experiment is needed, on the order of 60 μK. For similar reasons, and to avoid decoherence, the experimental device has to be in ultra-high vacuum conditions. The wavelength of the photons was calculated to be roughly 630 nm so the reflecting surfaces can be as small as possible and yet avoid refraction and reflectivity issues. The micromechanical-oscillator can be similar to the cantilevers in atomic force microscopy and the reflective surfaces typically used in similar high-demanding experiments pose no real challenge. Various elaborate electromagnetic mechanisms have been proposed to "reset" the cavities to a stable state before each repetition of the experiment.