Work

What structural length scales can be detected by the spectral variance of a microscope image?

Year: 2014

Type: article

Abstract: A spectroscopic microscope, configured to detect interference spectra of backscattered light in the far zone, quantifies the statistics of refractive-index (RI) distribution via the spectral variance (Σ˜2) of the acquired bright-field image. Its sensitivity to subtle structural changes within weakly scattering, label-free media at subdiffraction scales shows great promise in fields from material science to medical diagnostics. We further investigate the length-scale sensitivity of Σ˜ and reveal that, in theory, it can detect RI fluctuations at any spatial frequency whatsoever. Based on a 5% noise floor, Σ˜ detects scales from ∼22 to 200–700 nm (exact values depend on sample structure and thickness). In an example involving mass-density distribution characteristic of biological cell nuclei, we suggest the level of chromatin organization, which can be quantified via Σ˜.

Source: Optics Letters

DOI: 10.1364/ol.39.004290

Authors: Lusik Cherkezyan, Hariharan Subramanian, Vadim Backman

Institution: Northwestern University

Language: English

Topic: Digital Holography and Microscopy

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, National Institutes of Health, National Cancer Institute, National Institute of Biomedical Imaging and Bioengineering