1 April 1992 Improvement of spatial resolution in reflectance near-infrared imaging by laser-beam interference
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Abstract
The authors studied the use of destructive interference of two diffusive photon-density waves for localization of an absorbing body and a fluorescent probe embedded in a scattering medium. The effect of the position of the embedded objects on the magnitude and phase of the light re-emitted from the medium was evaluated theoretically and experimentally. The objectives, accomplished with an asymmetrical laser-beam arrangement, were to reduce sensitivity to absorbing bodies located in superficial layers, while maintaining sensitivity to those lying deeper; and to establish a confined region of maximum sensitivity in which the distance of an absorbing body could be determined via phase measurement. Intensity and phase data were acquired with a modified frequency-domain spectrometer at modulation frequencies up to 600 MHz. Fluorescent probes were spatially localized with a symmetrical laser-beam arrangement. Magnitude and phase images acquired with a gated intensified CCD camera further defined the probe location. Simulations and experiments show potential applications to imaging.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Alexander R. Knuettel, Joseph M. Schmitt, Jay R. Knutson, "Improvement of spatial resolution in reflectance near-infrared imaging by laser-beam interference", Proc. SPIE 1640, Time-Resolved Laser Spectroscopy in Biochemistry III, (1 April 1992); doi: 10.1117/12.58232; https://doi.org/10.1117/12.58232
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