What spatial light modulators can do for optical microscopy

Abstract

With the availability of high-resolution miniature spatial light modulators (SLMs) new methods in optical microscopy have become feasible. The SLMs discussed in this review consist of miniature liquid crystal displays with micronsized pixels that can modulate the phase and/or amplitude of an optical wavefront. In microscopy they can be used to control and shape the sample illumination, or they can act as spatial Fourier filters in the imaging path. Some of these applications are reviewed in this article. One of them, called spiral phase contrast, generates isotropic edge enhancement of thin phase samples or spiral-shaped interference fringes for thicker phase samples, which can be used to reconstruct the phase topography from a single on-axis interferogram. If SLMs are used for both illumination control and spatial Fourier filtering, this combination for instance allows for the generalization of the Zernike phase contrast principle. The new SLM-based approach improves the effective resolution and avoids some shortcomings and artifacts of the traditional method. The main advantage of SLMs in microscopy is their flexibility, as one can realize various operation modes in the same setup, without the need for changing any hardware components, simply by electronically switching the phase pattern displayed on the SLMs.

Diffraction-free space–time light sheets

“…The basic concept -as illustrated in Fig. 2 -combines spatial-beam modulation 33,34 and ultrafast pulse-shaping 35,36 , and is related to the so-called 4 -imager utilized to introduce ST-coupling into ultrafast pulsed beams for nonlinear spectroscopy and quantum control [37][38][39] . We start from a pulsed plane-wave ( , 0; ) = ( ), whose separable ST-spectrum is � ( , ) ≈ � ( ) ( ), and spread the spectrum along the -axis with a diffraction grating, so that each wavelength is assigned to a position ( ).…”

Controlling waves in space and time for imaging and focusing in complex media

“…Although this gives access to thousands of frequency degrees of freedom, the cost and size of the transducers required mean that only a small number (typically up to 100) spatial channels can be addressed. In the optical domain, however, CCD cameras and spatial light modulators (SLMs) 38 are able to address millions of spatial degrees of freedom, but within only a narrow frequency bandwidth.…”

Controlled Multibeam Supercontinuum Generation With a Spatial Light Modulator

“…The use of SLMs has benefited a wide range of applications in adaptive optics [20,21], scattering media [22] or optical microscopy [23]. In this Letter, we report active control of MF in a solid medium by codifying a diffractive microlens array in a phase-only SLM.…”