Deep-ultraviolet second harmonic generation by combined degenerate four-wave mixing and surface nonlinearity polarization on photonic crystal fiber

Yuan Jinhui, Zhe Kang, Feng Li, Guiyao Zhou, Xianting Zhang, Chao Mei, Xinzhu Sang, Qiang Wu, Binbin Yan, Xian Zhou, Kangping Zhong, Kuiru Wang, Chongxiu Yu, Lu Chao, Hwayaw Tam, Ping Kong Alexander Wai

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Deep-ultraviolet (UV) second-harmonics (SHs) have important applications in basic physics and applied sciences. However, it still remains challenging to generate deep-UV SHs especially in optical fibers. Here, for the first time, we experimentally demonstrate the deep-UV SH generations (SHGs) by combined degenerate four-wave mixing (FWM) and surface nonlinearity polarization in an in-house designed and fabricated air-silica photonic crystal fiber (PCF). When femtosecond pump pulses with average input power P av of 650 mW and center wavelength λ p of 810, 820, 830, and 840 nm are coupled into the normal dispersion region close to the zero-dispersion wavelength of the fundamental mode of the PCF, the anti-Stokes waves induced by degenerate FWM process are tunable from 669 to 612 nm. Then, they serve as the secondary pump, and deep-UV SHs are generated within the wavelength range of 334.5 to 306 nm as a result of surface nonlinearity polarization at the core-cladding interface of the PCF. The physical mechanism of the SHGs is confirmed by studying the dependences of the output power P SH of the SHs on the PCF length and time. Finally, we also establish a theoretical model to analyze the SHGs.
Original languageEnglish
Article number9224
JournalScientific Reports
Volume7
DOIs
Publication statusPublished - 2 Aug 2017

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