Coherent backscattering spectroscopy.
Coherent backscattering (CBS) of light in random media has been previously investigated by use of coherent light sources. Here we report a novel method of CBS measurement that combines low spatial coherence, broadband illumination, and spectrally resolved detection. We show that low spatial coherence illumination leads to an anomalously broad CBS peak and a dramatic speckle reduction; the latter is further facilitated by low temporal coherence detection. Thus CBS can be observed in biological tissue and other media that previously were beyond the reach of conventional CBS measurements. We also demonstrate, for the first time to our knowledge, spectroscopic analysis of CBS. CBS spectroscopy may find important applications in probing random media such as biological tissue in which depth-selective measurements are crucial.
Kim
Young L
YL
Department of Biomedical Engineering, Department of Gastroenterology, Northwestern University, Evanston, Illinois 60208, USA. younglae@northwestern.edu
Liu
Yang
Y
Turzhitsky
Vladimir M
VM
Roy
Hemant K
HK
Wali
Ramesh K
RK
Backman
Vadim
V
D000818:Animals; D004867:Equipment Design; D008029:Lighting; D051381:Rats; D012542:Scattering, Radiation; D013057:Spectrum Analysis / Q000295:instrumentation / Q000379:methods*