Elastic light scattering measurements collected in a transmission imaging configuration. Similar data may be collected in a reflectance configuration.

LEBS recorded from human colonic mucosa as a function of angle and wavelength.

Bax/Bak expressing (W2) and Bax/Bak null (D3) cells. A: Differential interference contrast, B: Dark field. C: Object orientation showing more highly oriented objects (red areas) in the W2 compared with the D3 cell. D & E: W2 and D3 orientation images after block-processing the initial Gabor filtered images to simulate a 4× demagnification. Data were collected using an orientation-sensitive Fourier filter bank consisting of nine Gabor-like filters with period S=0.95μm, Gaussian envelope standard deviation s=S/2=0.45 μm, and orientations φ=0° to φ=160° in 20° increments (See also (7)). The color intensity in panels C, D, and E represents the overall response (sum of all responses) of the pixel to the filter bank; the color hue encodes degree of orientation or “Aspect Ratio”. The ratio of maximum intensity to the average of all the responses collected as a function of filter orientation was taken as a measure of aspect ratio. F&G: Pixel histograms of all W2 and D3 cells before (F) and after (G) pixel binning. In F, the mean aspect ratio parameter per cell was 1.58 for W2; 1.38 for D3 (p<0.04 by student t-test), and in G, 1.54 for W2; 1.35 for D3 (p<0.05 by student t-test).

Optical scatter spectroscopy. A. Energy diagram illustration of light-matter interaction based on elastic light scattering. B&C: Elastically scatterd light may be analyzed as a function of wavelength and scattering angle to extract information about particle size and refractive index. The blue scattergram corresponds to a numerical simulation of light scattering by the small blue sphere in panel B; the red scattergram to the larger red sphere in panel B. A plane wave with wavelength λ=λ_o/n_m is incident on the spheres which have refractive index n_p=1.38 and are located in a medium with refractive index n_m=1.33.

A: Phase sensitive light scattering measurements collected in an interferometer. B: Low coherence interferometry utilizing a broad band source can be used to collect depth resolved reflectance data I(z) which can be processed to obtain three-dimensional images of the sample (optical coherence tomorgraphy). C: Holograms of the sample object, I(x,y), may be collected and digitally processed to obtain quantitative phase images.

Spectroscopic OCT imaging using time-domain and frequency-domain interferometry. Short-time and short-frequency Fourier transforms are performed on the acquired OCT interferograms to create 2-D SOCT signals that are indexed by wavelength and depth in the sample or specimen. Top Right Set: Spectroscopic spectral-domain OCM. A) OCM of rat tissue containing regions of adipose cells (middle) and muscle fibers (upper right, lower left). B) Corresponding histology. C) SOCM image using metameric spectral analysis. D) SOCM image using LSS spectral analysis. The scale bar is representative of all images. Bottom Right Set: Single-cell imaging with SOCM. A) Spectral-domain OCM of GFP-vinculin transfected fibroblasts in culture. B) Corresponding SOCM image showing localized regions of strong spectral scattering (yellow-green). C) Multiphoton microscopy of GFP fibroblasts co-labeled with DNA-nuclear dye. D) Overlay of multiphoton DNA-dye fluorescence and OCM images. Comparisons between (C) and (D) show validation of SOCM spectral analysis for identifying dominant scatterers. Figures adapted from (37 and 78).

Interferometric Synthetic Aperture Microscopy (ISAM). Top: Three-dimensional images of a tissue phantom composed of micron-sized point-scatterers of titanium dioxide suspended in a gel. OCT (top left) shows blurred out-of-focus scatterers near the upper surface, which are corrected to the appropriate point-like objects using ISAM (top right). Bottom: Human breast tissue. En face OCT images (labeled unprocessed data) and corresponding ISAM image reconstructions from two different slices/depths within a three-dimensional block of tissue. ISAM images enable fine cellular membranes and features to be resolved. Histology sections taken from approximate locations are also shown for comparison. Figure adapted from (120).