By use of a highly sensitive method for measuring slight variations in birefringence it is shown here that a strong reversible correlation exists between rat tail tendon birefringence and temperature. This phenomenon is totally different from the loss of birefringence that results from a denaturation process. Below the threshold temperature leading to denaturation, an increase in temperature is systematically accompanied by a reversible increase in birefringence (0.25% °C<sup>−1</sup>). This phenomenon is observed at very fast heating rates (250,000 °C s<sup>−1</sup>), such as those induced by pulsed infrared lasers, and confirmed by experiments conducted with slow homogeneous heating of the sample medium (0.1 °C s<sup>−1</sup>). The good correlation between birefringence and temperature observed during the fast heating suggests that there are only small modifications of the tissue structure at the fibril level.
© 2000 Optical Society of America
(120.5410) Instrumentation, measurement, and metrology : Polarimetry
(170.4580) Medical optics and biotechnology : Optical diagnostics for medicine
(170.6920) Medical optics and biotechnology : Time-resolved imaging
(260.1440) Physical optics : Birefringence
(350.5340) Other areas of optics : Photothermal effects
Didier Beghuin, Klaus Schönenberger, Guy Delacrétaz, and René Paul Salathé, "Temperature-Related Reversible Birefringence Changes in Rat Tail Tendon," Appl. Opt. 39, 3388-3395 (2000)