Highly Efficient and Broadband Cherenkov Radiation at the Visible Wavelength in the Fundamental Mode of Photonic Crystal Fiber

Highly efficient and broadband Cherenkov radiations (CRs) by soliton self-frequency shift (SSFS) are generated in the fundamental mode of photonic crystal fiber (PCF) fabricated in our laboratory. The dependences of CR on the pump wavelength and power are investigated, and the corresponding nonlinear-optical processes are discussed. When the average power of the 120-fs pump pulse increases from 100 to 300 mW, the Raman soliton shifts from 1970 to 2130 nm, the conversion efficiency of CR in the range of 580 to 545 nm increases from 8% to 31%, and the width of output optical spectrum at the visible wavelength broadens from 11 to 54 nm.