Abstract (eng)
In optomechanical systems, the optical and mechanical properties of the mechanical resonator are of great importance. There do already exist various types of resonators of different shapes and materials, but there is still the need for improvement.
In this thesis, the optical and mechanical properties of three mechanical devices are investigated. First, structures with an additional silicon pillar between the mechanical resonator and the mirror pad, which should entail better decoupling of the mechanics from the environment, are introduced. Then, a completely new generation of photonic crystal membranes is explored. They are designed such that a laser beam of a certain wavelength hitting them perpendicularly is reflected with a reflectivity approaching 1. This, in combination with mechanical quality factors around 10^6, makes these devices promising new optomechanical structures. Finally, the mechanical quality factors for commercial stiochiometric silicon nitride membranes are measured for various holders and clamping methods at room temperature and cryogenic temperatures. The results of Q > 10^6 for certain modes with clamping that touches the membrane as little as possible, and the fact that at low temperatures there is an enhancement of Q of almost a factor of 5, are in good agreement with previous results from other groups.