Efficient and broadband Cherenkov radiations in the multi-knots of a hollow-core photonic crystal fiber cladding

Abstract: The Cherenkov radiations (CRs) at visible wavelengths are efficiently generated based on the soliton self-frequency shift (SSFS) by coupling the 120fs pulses into the fundamental mode propagated in the multi-knots of a hollow-core photonic crystal fiber cladding (HC-PCFC). When the pump operates at 830nm with the average power of 300mW at the knots 1–4 , the central wavelengths of generated CRs λ CR are 476nm, 454nm, 554nm, and 580nm, the conversion efficiencies η CR are 33%, 35%, 30%, and 29%, and the corresponding bandwidths B CR are 57nm, 74nm, 25nm, and 50nm, respectively. To the best of our knowledge, η CR of 35% and B CR of 74nm are the best experimental results reported with >100fs pump pulse. The efficient and broadband CRs can be wavelength-tunable over the whole visible wavelength by adjusting the wavelengths of pump pulses coupled into different knots. The result can be used as the multi-channel ultrashort pulse source for many important applications in the multiphoton microscope and ultrafast photonics. [Copyright &y& Elsevier]