Time-averaged computer generated holography for the estimation of torsional amplitudes of oscillating microdevices

Abstract

Time-averaged geometric moiré technique has been applied in various areas including experimental interpretation of moiré patterns in order to determine the amplitudes of the oscillations of microdevices and inverse moiré pattern synthesis for construction of dynamic visual cryptography schemes. Another common component in optical setups are diffractive optical elements. Computational algorithms can be used to design diffractive optical elements in the form of a computer generated hologram of a nonexistent, synthetic or even a virtual object. The main goal of this paper is to demonstrate the feasibility of the optical scheme based on the integration of time-averaged geometric moiré and computer generated holography. We present the design of the optical setup, derive the equations governing the formation of time-averaged fringes in the optical projection plane and validate the results by performing computational simulations of the formation of time-averaged fringes when torsional oscillations are performed. This approach has promising applications as an optical scale for the quantitative estimation of the amplitude of torsional oscillations as well as the validation of microdevices when the amplitude of torsional oscillations experience fluctuations due to environmental conditions and degradation.