Deformation behavior of thin viscoelastic layers used in an active-matrix-addressed spatial light modulator

Thin viscoelastic layers with active-matrix addressing are proposed as high-resolution spatial light modulators (SLMs) for use in a reflective schlieren light valve. Light modulation is achieved by diffraction from the periodically deformed mirror electrode covering the SLM layer. A two-dimensional array of Si-MOS transistors will be employed for addressing the viscoelastic SLM. Orthogonal and diagonally offset arrangements of pixels with two grating periods each are suggested for this active matrix. For measuring the deformation behavior of viscoelastic layers with a reflective top electrode, a standard microscope interferometer was modified so that the phase-shift technique could be employed. The deformation profile is recorded by means of a CCD image sensor, while the temporal development of the deformation is detected with a photomultiplier tube. Qualitatively, the experimental results agree with previously obtained predictions from an extensive theoretical analysis of the SLMs time behavior and spatial-frequency response.