6533b821fe1ef96bd127c0b7

RESEARCH PRODUCT

Time-multiplexed chromatic-controlled axial diffractive optical elements

subject

description

Programmable diffractive optical elements DOEs with axial response have many interesting applications, including diffractive lenses, axicons, and optical tweezers. In all these cases, it is essential to properly select the modulation configuration of the spatial light modulator SLM where the DOE is displayed, in order to avoid the undiffracted zero order component that appears on axis and overlaps the desired axial response. However, in general, the chromatic dispersion in liquid crystal SLMs prevents the cancellation of the zero order for a broadband light source, thus limiting the possibilities for polychromatic program- mable axial DOEs. We operate a ferroelectric liquid crystal on silicon display with polychromatic illumination and with a specific polarization configuration that provides binary -phase modulation for all wave- lengths. Since this type of modulation cancels the undiffracted zero or- der, we use this SLM to display DOEs with axial response. Moreover, chromatic control is achieved by time-multiplexing sequences of properly scaled DOEs with the corresponding selection of the input wavelength by means of an electronically controlled color-filter wheel. The presented experimental results include wavelength-controlled diffraction gratings, axicons, and vortex-producing lenses. © 2010 Society of Photo-Optical Instru-