Second-harmonic optical coherence tomography, which uses coherence gating of second-order nonlinear optical responses of biological tissues for imaging, is described and demonstrated. Femtosecond laser pulses were used to excite second-harmonic waves from collagen harvested from rat tail tendon and a reference nonlinear crystal. Second-harmonic interference fringe signals were detected and used for image construction. Because of the strong dependence of second-harmonic generation on molecular and tissue structures, this technique imparts contrast and resolution enhancement to conventional optical coherence tomography.
© 2004 Optical Society of America
(170.3880) Medical optics and biotechnology : Medical and biological imaging
(170.4500) Medical optics and biotechnology : Optical coherence tomography
(190.4160) Nonlinear optics : Multiharmonic generation
Yi Jiang, Ivan Tomov, Yimin Wang, and Zhongping Chen, "Second-harmonic optical coherence tomography," Opt. Lett. 29, 1090-1092 (2004)