Two applications of liquid crystal displays in diffractive optics under polychromatic illumination

A. MÁRQUEZ; CLAUDIO IEMMI; J. CAMPOS; J. ESCALERA; M. YZUEL

Estrasburgo, Francia

Congreso; SPIE's International Symposium: Photonics Europe; 2006

The amplitude and phase modulations provided by a liquid-crystal spatial light modulator (LCSLM) depend strongly on the wavelength used for illumination. This is the main reason why usually LCSLMs are only applied with monochromatic illumination. However, there are a number of potential applications where it would be very interesting to combine the programmability provided by LCSLMs and the use of non-monochromatic illumination. In this work we focus on two such applications. On one hand, we use an axial apodizing filter to compensate the longitudinal secondary axial color (LSAC) effects of a commercial refractive optical system on the polychromatic point-spread function (PSF). The configuration of the LCSLM has been optimized to obtain the amplitude-mostly regime in polychromatic light. On the other hand, we show a programmable diffractive lens which is able to provide equal focal length for several wavelengths simultaneously. To achieve this achromatization it is necessary that the LCD operates in the phase-only regime simultaneously for the different wavelengths. Both experimental and numerical results will be provided in this work showing the feasibility of the two applications, and thus the use of LCSLMs under non-monochromatic illumination.