Taking Two-Photon Excitation to Exceptional Path-Lengths in Photonic Crystal Fiber
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- 作者：Gareth O. S. Williams ; Tijmen G. Euser ; Jochen Arlt ; Philip St.J. Russell ; Anita C. Jones
- 刊名：ACS Photonics
- 出版年：2014
- 出版时间：September 17, 2014
- 年：2014
- 卷：1
- 期：9
- 页码：790-793
- 全文大小：394K
- ISSN：2330-4022
文摘
The well-known, defining feature of two-photon excitation (TPE) is the tight, three-dimensional confinement of excitation at the intense focus of a laser beam. The extremely small excitation volume, on the order of 1 渭m3 (1 femtoliter), is the basis of far-reaching applications of TPE in fluorescence imaging, photodynamic therapy, nanofabrication, and three-dimensional optical memory. Paradoxically, the difficulty of detecting photochemical events in such a small volume is a barrier to the development of the two-photon-activated molecular systems that are essential to the realization of such applications. We show, using two-photon-excited fluorescence to directly visualize the excitation path, that confinement of both laser beam and sample solution within the 20 渭m hollow core of a photonic crystal fiber permits TPE to be sustained over an extraordinary path-length of more than 10 cm, presenting a new experimental paradigm for ultrasensitive studies of two-photon-induced processes in solution.