Article

Quantitative DIC microscopy using an off-axis self-interference approach

G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Optics Letters (Impact Factor: 3.29). 07/2010; 35(14):2370-2. DOI: 10.1364/OL.35.002370
Source: PubMed

ABSTRACT

Traditional Normarski differential interference contrast (DIC) microscopy is a very powerful method for imaging nonstained biological samples. However, one of its major limitations is the nonquantitative nature of the imaging. To overcome this problem, we developed a quantitative DIC microscopy method based on off-axis sample self-interference. The digital holography algorithm is applied to obtain quantitative phase gradients in orthogonal directions, which leads to a quantitative phase image through a spiral integration of the phase gradients. This method is practically simple to implement on any standard microscope without stringent requirements on polarization optics. Optical sectioning can be obtained through enlarged illumination NA.

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    • "This is very well know in the field of classical image processing where appropriate kernels are adopted for performing spatial derivative with these aims. Actually, research in PCI field is basically divided in two branches: (i) direct recovering of the quantitative PCI map by interferometric and/or holographic methods [4–6] or (ii) QPM computation starting from classical DIC experimental analysis [7,8]. Several groups are still working on recovering quantitative information from DIC with the two following motivations. "
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    • "It is hard to disentangle the contribution of biomolecule spatial distribution and laser speckle noise with the current setup. This problem could potentially be alleviated with phase measurement based on a spatially incoherent source which has much less speckle noise [14]. "
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    ABSTRACT: Microscopy is one of the main research and application areas of digital holography. Direct access to the phase as well as amplitude profiles makes quantitative phase microscopy by digital holography (DH-QPM) particularly powerful and versatile. A number of techniques of DH are developed especially for microscopy imaging and these are made possible because of the particular imaging characteristics of DH. Digital holographic and interferometric principles are the basis of many other techniques of QPM with novel capabilities. A survey is given of the wide and very active field of research in DHM techniques and applications. We begin with a brief background on optical microscopy.
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