Optomechanical characterization of silicon nitride membrane arrays

We report on the optical and mechanical characterization of arrays of parallel micromechanical membranes. Pairs of high-tensile stress, 100 nm thick silicon nitride membranes are assembled parallel to each other with separations ranging from 8.5 to 200 μm. Their optical properties are accurately determined using transmission measurements under broadband and monochromatic illuminations, and the lowest vibrational mode frequencies and mechanical quality factors are determined interferometrically. The results and techniques demonstrated are promising for investigations of collective phenomena in optomechanical arrays.