New paper in Optics Letters about a new technique of measuring the LCOS backplane deformation
A new paper is available in Optics Letters entitled Measuring the spatial deformation of a liquid-crystal on silicon display with a self-interference effect.
Here we present a simple technique to characterize the spatial non-uniformity of a LCOS-SLM, based on illuminating the display with a wavelength out of the operation range. In this situation there is a significant reflection at the output surface and a Gires–Tournois type interferometer is directly created, without any alignment requirement and insensitive to vibrations. The beam reflected at the output surface is the reference beam, while the beam reflected at the silicon backplane is modulated with the addressed gray level in order to quantitatively derive its deformation. We provide an experimental demonstration using a LCOS-SLM designed to operate in the near-infrared range but illuminated with visible light.
This work is part of the PhD Thesis of David Marco and has been done in collaboration with our colleague Prof. Asticio Vargas, from Universidad de La Frontera, Temuco, Chile.