Related Experiment Video
Updated: Feb 24, 2026

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Deep-ultraviolet second-harmonic generation by combined degenerate four-wave mixing and surface nonlinearity
Jinhui Yuan1,2,3, Zhe Kang4, Feng Li5,6
1State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), P.O. Box 72 (BUPT), 100876, Beijing, China.
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.

