Origins of subdiffractional contrast in optical coherence tomography.

We demonstrate that OCT images quantify subdiffractional tissue structure. Optical coherence tomography (OCT) measures stratified tissue morphology with spatial resolution limited by the temporal coherence length. Spectroscopic OCT processing, on the other hand, has enabled nanoscale sensitive analysis, presenting an unexplored question: how does subdiffractional information get folded into the OCT image and how does one best analyze to allow for unambiguous quantification of ultrastructure? We first develop an FDTD simulation to model spectral domain OCT with nanometer resolution.

Characterizing chromatin packing scaling in whole nuclei using interferometric microscopy.

Chromatin is the macromolecular assembly containing the cell's genetic information, and its architectural conformation facilitates accessibility to activation sites and thus gene expression. We have developed an analytical framework to quantify chromatin structure with spectral microscopy. Chromatin structure can be described as a mass fractal, with packing scaling up to specific genomic length scales.

Cascaded spintronic logic with low-dimensional carbon.

Remarkable breakthroughs have established the functionality of graphene and carbon nanotube transistors as replacements to silicon in conventional computing structures, and numerous spintronic logic gates have been presented. However, an efficient cascaded logic structure that exploits electron spin has not yet been demonstrated. In this work, we introduce and analyse a cascaded spintronic computing system composed solely of low-dimensional carbon materials.

Review of interferometric spectroscopy of scattered light for the quantification of subdiffractional structure of biomaterials.

Optical microscopy is the staple technique in the examination of microscale material structure in basic science and applied research. Of particular importance to biology and medical research is the visualization and analysis of the weakly scattering biological cells and tissues. However, the resolution of optical microscopy is limited to ? 200 ?? nm due to the fundamental diffraction limit of light.

Finite-difference time-domain-based optical microscopy simulation of dispersive media facilitates the development of optical imaging techniques.

Combining finite-difference time-domain (FDTD) methods and modeling of optical microscopy modalities, we previously developed an open-source software package called Angora, which is essentially a “microscope in a computer.” However, the samples being simulated were limited to nondispersive media. Since media dispersions are common in biological samples (such as cells with staining and metallic biomarkers), we have further developed a module in Angora to simulate samples having complicated dispersion properties, thereby allowing the synthesis of microscope images of most biological samples.