Direct calibration of a spatial light modulator by lateral shearing interferometry

Abstract

A new interferometric technique is described to measure the complex modulation curve of a spatial light modulator. Based on a lateral shear imaging interferometer, it enables the amplitude and phase modulation for several modulation levels to be displayed simultaneously in a single interferogram. As an example of the power of this technique a heuristic optimization of input and output elliptical polarization states for a mostly-phase operation mode was obtained within a few minutes for a commercial twisted-nematic liquid crystal display.

Phase and amplitude calibration of dual‐mask spatial light modulator for high‐resolution femtosecond pulse shaping

“…As the extraordinary axes of the LC panels are placed orthogonally to each other and a polarisation filter is placed at the exit of the shaper, the polarisation rotation caused by a difference in extraordinary phase retardation ΔΦ i ( V i ) between the panels leads to an attenuation term [1] whereas the sum of the extraordinary phase retardations leads to a phase shift [1] Amplitude and phase can therefore be independently controlled by this kind of pulse shaper. Phase–voltage calibration methods for SLMs can be divided into methods directly measuring the phase retardance by interferometry [9–11] and methods investigating the attenuation of the SLM between polarisers [12, 13]. Interferometric phase–voltage calibration methods measure the result of (2), attenuation methods measure (1).…”

“…Amplitude and phase can therefore be independently controlled by this kind of pulse shaper. Phase-voltage calibration methods for SLMs can be divided into methods directly measuring the phase retardance by interferometry [9][10][11] and methods investigating the attenuation of the SLM between polarisers [12,13]. Interferometric phase-voltage calibration methods measure the result of (2), attenuation methods measure (1).…”

Diffraction-Based Phase Calibration of Spatial Light Modulators With Binary Phase Fresnel Lenses

“…The position dependent phase response of a transmissive SLM is measured and corrected in [14] with a Mach-Zehnder interferometer, including optical elements like polarizing beam splitters or two-lens Kepler-type imaging optics. A method, based on a shear interferometer, able to simultaneously measure the amplitude and phase modulation of a twisted liquid crystal display, in a relative simple manner, is shown in [15]. Here, it should be noted that apart from the inherent drawbacks related to the alignment of interferometers, as well as their high sensitivity to mechanical vibrations or air turbulences, above-mentioned calibration setups required a large number of optical elements.…”

Spatially resolved scatter measurement of diffractive micromirror arrays

“…The phase accuracy is a key factor for many application-relevant parameters, e.g., the contrast ratio and gray-level performance in projection applications or the diffraction efficiency in holography. Consequently, special focus is being directed to the accurate calibration of the phase modulation, which has become a burgeoning field of active research [12][13][14][15][16].…”