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University of Massachusetts Boston

Physics Faculty Publications

Holographic gratings

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Full-Text Articles in Physical Sciences and Mathematics

Medical Image Processing Using Transient Fourier Holography In Bacteriorhodopsin Films, Sri-Rajasekhar Kothapalli, Pengfei Wu, Chandra S. Yelleswarapu, D.V.G.L.N. Rao Dec 2004

Medical Image Processing Using Transient Fourier Holography In Bacteriorhodopsin Films, Sri-Rajasekhar Kothapalli, Pengfei Wu, Chandra S. Yelleswarapu, D.V.G.L.N. Rao

Physics Faculty Publications

Real time image processing is demonstrated by recording and reconstructing the transient photoisomerizative grating formed in the bR film using Fourier holography. Desired spatial frequencies including both high and low band in the object beam are reconstructed by controlling the reference beam intensity. The results are in agreement with a theoretical model based on photoisomerization grating. We exploit this technique to process mammograms in real-time for identification of microcalcifications buried in the soft tissue for early detection of breast cancer. A feature of the technique is the ability to transient display of selected spatial frequencies in the reconstructing process which …


Nonvolatile Grating In An Azobenzene Polymer With Optimized Molecular Reorientation, Pengfei Wu, D.V.G.L.N. Rao, B. R. Kimball, M. Nakashima, B. S. Decristofano Feb 2001

Nonvolatile Grating In An Azobenzene Polymer With Optimized Molecular Reorientation, Pengfei Wu, D.V.G.L.N. Rao, B. R. Kimball, M. Nakashima, B. S. Decristofano

Physics Faculty Publications

We demonstrated a nonvolatile grating using an azobenzene polymer film with polarized two color beams. The reorientation of azobenzene molecules can be optimized when the two color light beams are polarized perpendicularly. The stored information can be read repeatedly without volatility with the same wavelength as the writing beam.