Interferometric synthetic aperture microscopy,”

ABSTRACT Optical coherence tomography (OCT) is an optical ranging technique analogous to radar -detection of back-scattered light produces a signal that is temporally localized at timesof-flight corresponding to the location of scatterers in the object. However the interferometric collection technique used in OCT allows, in principle, the coherent collection of data, i.e. amplitude and phase information can be extracted. Interferometric Synthetic Aperture Microscopy (ISAM) adds phasestable data collection to OCT instrumentation and employs physics-based processing analogous to that used in Synthetic Aperture Radar (SAR). That is, the complex nature of the coherent data is exploited to give gains in image quality. Specifically, diffraction-limited resolution is achieved throughout the sample, not just within focal volume of the illuminating field. Simulated and experimental verifications of this effect are presented. ISAM's computational focusing obviates the trade-off between lateral resolution and depth-of-focus seen in traditional OCT

Interferometric Synthetic Aperture Microscopy: Computed Imaging for Scanned Coherent Microscopy

Three-dimensional image formation in microscopy is greatly enhanced by the use of computed imaging techniques. In particular, Interferometric Synthetic Aperture Microscopy (ISAM) allows the removal of out-of-focus blur in broadband, coherent microscopy. Earlier methods, such as optical coherence tomography (OCT), utilize interferometric ranging, but do not apply computed imaging methods and therefore must scan the focal depth to acquire extended volumetric images. ISAM removes the need to scan the focus by allowing volumetric image reconstruction from data collected at a single focal depth. ISAM signal processing techniques are similar to the Fourier migration methods of seismology and the Fourier reconstruction methods of Synthetic Aperture Radar (SAR). In this article ISAM is described and the close ties between ISAM and SAR are explored. ISAM and a simple strip-map SAR system are placed in a common mathematical framework and compared to OCT and radar respectively. This article is intended to serve as a review of ISAM, and will be especially useful to readers with a background in SAR

Using multi-element detectors to create optimal apertures in confocal microscopy

Abstract — A detection pinhole is used in confocal microscopy to reduce contributions from image planes outside of the focal plane. The size of this pinhole may be varied but the idea of a fixed circular aperture is ubiquitous. Here it is shown that an ideal detection aperture varies as a function of the spatial-frequency being imaged. A method for calculating such detection apertures is given, an example calculation is shown and a detector array is suggested as a means to approximate these varying detection apertures. I

Interferometric synthetic aperture microscopy (accepted),” Nature Physics,

ABSTRACT Optical coherence tomography (OCT) is an optical ranging technique analogous to radar -detection of back-scattered light produces a signal that is temporally localized at timesof-flight corresponding to the location of scatterers in the object. However the interferometric collection technique used in OCT allows, in principle, the coherent collection of data, i.e. amplitude and phase information can be extracted. Interferometric Synthetic Aperture Microscopy (ISAM) adds phasestable data collection to OCT instrumentation and employs physics-based processing analogous to that used in Synthetic Aperture Radar (SAR). That is, the complex nature of the coherent data is exploited to give gains in image quality. Specifically, diffraction-limited resolution is achieved throughout the sample, not just within focal volume of the illuminating field. Simulated and experimental verifications of this effect are presented. ISAM's computational focusing obviates the trade-off between lateral resolution and depth-of-focus seen in traditional OCT