Quantitative SLM-based differential interference contrast imaging

Abstract

We describe the implementation of quantitative Differential Interference Contrast (DIC) Microscopy using a spatial light modulator (SLM) as a flexible Fourier filter in the optical path. The experimental arrangement allows for the all-electronic acquisition of multiple phase shifted DIC-images at video rates which are analyzed to yield the optical path length variation of the sample. The resolution of the technique is analyzed by retrieving the phase profiles of polystyrene spheres in immersion oil, and the method is then applied for quantitative imaging of biological samples. By reprogramming the diffractive structure displayed at the SLM it is possible to record the whole set of phase shifted DIC images simultaneously in different areas of the same camera chip. This allows for quantitative snap-shot imaging of a sample, which has applications for the investigation of dynamic processes.

Rapid quantitative phase imaging for partially coherent light microscopy

“…The DSC can be tuned in several ways, for example, by spatial filtering of the incoherent source or by using a moving diffuser in the case of a coherent source (e.g. laser) [22][23][24]. We underline that a pinhole of few microns (e.g.…”

Quantitative analysis of shape and volume changes in activated thrombocytes in real time by single‐shot spatial light modulator‐based differential interference contrast imaging

“…by integrating over the phase gradient information of multiple DIC images recorded with different offset phases and, sometimes, different image orientations. For this purpose a number of (usually 6) different images [14][15][16] is needed, the recording of which takes a few seconds, irrespective whether one implements the different shear directions mechanically or rather optically by means of a spatial light modulator (SLM). Unfortunately, the shape changes during platelet activation occur very fast, typically also within a few seconds after the addition of agonists inducing activation to the sample volume.…”

“…The imaging setup is based on a recently introduced DIC method [15], where the Wollaston prism of a classical DIC microscope is replaced by a spatial light modulator (SLM). The SLM is placed in a Fourier plane of the imaging path behind the imaging objective.…”

“…After multiplying the three images with a complex phase term exp (i n ) (where n is the phase bias used during recording of the respective DIC image) and adding the three (now) complex images the phase of the complex sum corresponds to the desired phase gradient of the sample [15]. Using six images, i.e.…”

“…From the processed images the phase gradients Df x and Df y along the x-and y-axis are calculated. Finally the phase map fðx; yÞ of the sample, which is proportional to its optical thickness ' was calculated according to [15]:…”