Abstract

The general behavior of two-photon absorption-enhanced refractive-index change in a third-order nonlinear optical medium is briefly described. The nonlinear medium was the solution of a new dye, trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl]-N-methyl pyridinium iodide (ASPI) in dimethyl sulfoxide as the solvent, that was poured into a 20-cm-long quartz hollow fiber of 100-µm internal diameter. This dye solution has a strong two-photon absorption and subsequent upconversion fluorescence emission when excited with 1064-nm laser radiation. When the input peak intensity reached 500–1500-MW/cm² levels, obvious changes in beam profiles of the output IR laser beam were observed due to a self-focusing or self-trapping process occurring inside the fiber system. As a result of this process, highly directional frequency-upconverted superradiant lasing output was obtained with a beam size ∼5 times smaller than that of a linearly transmitted He–Ne probe laser beam. The demonstrated mechanism can be useful for fiber laser–amplifier and fiber–integrated optics devices.

© 1997 Optical Society of America

Optical limiting, pulse reshaping, and stabilization with a nonlinear absorptive fiber system

Guang S. He, Lixiang Yuan, Jayant D. Bhawalkar, and Paras N. Prasad
Appl. Opt. 36(15) 3387-3392 (1997)

Two-photon-pumped cavity lasing in a dye-solution-filled hollow-fiber system

Guang S. He, Jayant D. Bhawalkar, Chan F. Zhao, Chi-Kyun Park, and Paras N. Prasad
Opt. Lett. 20(23) 2393-2395 (1995)

Studies on the two-photon pumped upconverted fluorescence and superradiance of a new organic dye material in solutions

Guangyong Zhou, Dong Wang, Shengjun Yang, Xinguang Xu, Yan Ren, Zongshu Shao, Minhua Jiang, Yupeng Tian, Fuying Hao, Shengli Li, and Pengfei Shi
Appl. Opt. 41(30) 6371-6374 (2002)

Optical properties of a new two-photon absorbing chromophore

Chun Wang, Xiaomei Wang, Zongshu Shao, Xian Zhao, Guangyong Zhou, Dong Wang, Qi Fang, and Minhua Jiang
Appl. Opt. 40(15) 2475-2478 (2001)

Phase-conjugate backward stimulated emission from a two-photon-pumped lasing medium

Guang S. He, Yiping Cui, Makoto Yoshida, and Paras N. Prasad
Opt. Lett. 22(1) 10-12 (1997)