Simultaneous three-photon excited stimulated emission at (cavityless lasing) ~610nm has been achieved in an organic chromophore solution pumped by ~1.5-μm ultrashort coherent radiation. The stimulated emission can be observed only in the forward and backward directions and is characterized by its high directionality and spectral narrowing. The divergence angle for the backward stimulated emission is considerably smaller than that for the forward stimulated emission, which resembles optical phase conjugation.
© 2003 Optical Society of America
(100.3010) Image processing : Image reconstruction techniques
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(190.4180) Nonlinear optics : Multiphoton processes
(190.5040) Nonlinear optics : Phase conjugation
Guang S. He, Jianming Dai, Tzu-Chau Lin, Przemyslaw P. Markowicz, and Paras N. Prasad, "Ultrashort 1.5-μm laser excited upconverted stimulated emission based on simultaneous three-photon absorption," Opt. Lett. 28, 719-721 (2003)