We demonstrate significant differences in the propagation of polarized ligh
t through biological tissue compared with two common tissue phantoms. Depol
arization of linearly and circularly polarized light was measured versus pr
opagation distance by use of two independent measurement techniques. The me
asurements were performed on adipose and myocardial tissues and on tissue p
hantoms that consisted of polystyrene microsphere suspensions and Intralipi
d. The results indicate that, in contrast with results obtained in tissue p
hantoms, linearly polarized light survives through longer propagation dista
nces than circularly polarized light in biological tissue. (C) 1999 Optical
Society of America.