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.

We investigate the dynamics of a mechanical resonator in which is embedded an ensemble of two-level systems interacting with an optical cavity field. We show that this hybrid approach to optomechanics allows for enhanced effective interactions between the mechanics and the cavity field, leading for instance to ground state cooling of the mechanics, even in regimes, like the unresolved sideband regime, in which standard radiation pressure cooling would be inefficient.Comment: 9 pages, 4 figure

Optomechanical arrays made of structured flexible dielectrics are a promising system for exploring quantum and many-body optomechanical phenomena. We generalize investigations of the optomechanical properties of periodic arrays of one-dimensional scatterers in optical resonators to the case of vibrating membranes whose thickness is not necessarily small with respect to the optical wavelength of interest. The array optical transmission spectrum and its optomechanical coupling with a linear Fabry-Perot cavity field are investigated both analytically and numerically.

We report on the realization of silicon nitride membranes with enhanced and electrically tunable reflectivity. A high contrast grating is directly patterned using electron beam lithography on suspended 200 nm-thick, high stress commercial films. We show that the grating transverse profile can be measured in situ using localized cuts of the suspended film with a Focused Ion Beam. A Fano resonance is observed at 937 nm in the transmission spectrum of TM polarized light impinging on the membrane at normal incidence, leading to an increase in its reflectivity from 10% to 78%. By mounting membrane chip on a ring piezoelectric transducer and applying a compressive force to the corners of the film we subsequently show that it is possible to shift the transmission spectrum by 0.23 nm.

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