Virtual aperture culling of the eigenmodes of a resonator (VACER) is a technique to focus light within turbid media at arbitrary locations. A seed pulse of light is directed through a phase-conjugate mirror (PCM) into a turbid medium. Though much of the light may be lost, any light which reaches the second PCM is phase conjugated and thus returned to the first PCM where the light will be phase conjugated again. Amplification by the PCMs can prevent decay of the light cycling between the PCMs. Introducing a mechanism which filters light based on position enables attenuation of the modes not traveling through the center of the virtual aperture resulting in a focusing of light at the center of the virtual aperture. The seed pulse and the positioning of the PCMs on opposite sides of the virtual aperture ensure that modes cannot bypass the virtual aperture. Magnetic fields and ultrasound waves are potential means for implementation of a virtual aperture. Generally, only weak filtration mechanisms like magnetic fields and ultrasound waves are innocuous to turbid media. Fortunately, weak effects can strongly cull modes in VACER because the filtration mechanism affects the modes during each pass between PCMs and the modes compete. A combination of theory and computational modeling prove that sound physical principles underlie VACER. Moreover, computational modeling reveals how mode overlap, the seed pulse, and other variables impact VACER performance. Good experimental performance is predicted.
|Advisor:||Dunn, Andrew K.|
|School:||The University of Texas at Austin|
|School Location:||United States -- Texas|
|Source:||DAI-B 75/04(E), Dissertation Abstracts International|
|Subjects:||Biomedical engineering, Optics|
|Keywords:||Lasers, Mode competition, Multiple scattering, Phase conjugation, Virtual aperture culling|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be