title: Fiber-optic Cherenkov radiation in the few-cycle regime.
abstract: Fiber-optic Cherenkov radiation has emerged as a wavelength conversion technique to achieve isolated spectrum in the visible wavelength range. Most published results have reinforced the impression that CR forms a narrowband spectrum with poor efficiency. We both theoretically and experimentally investigate fiber-optic Cherenkov radiation excited by few-cycle pulses. We introduce the coherence length to quantify the Cherenkov-radiation bandwidth and its dependence on propagation distance. Detailed numerical simulations verified by experimental results reveal three unique features that are absent when pumped with often-used, long pulses; that is, continuum generation (may span one octave in connection with the pump spectrum), high conversion efficiency (up to 40%), and broad bandwidth (70 nm experimentally obtained) for the isolated Cherenkov radiation spectrum. These merits allow achieving broadband visible-wavelength spectra from low-energy ultrafast sources which opens up new applications (e.g. precision calibration of astronomical spectrographs).
authors: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. guoqing@mit.edu
authors: Guoqing
authors: G
authors: Chang
authors: Li-Jin
authors: LJ
authors: Chen
authors: Franz X
authors: FX
authors: Kärtner
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004574:Electromagnetic Fields; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D008027:Light; D008029:Lighting / Q000295:instrumentation*; D008962:Models, Theoretical; D055096:Optical Devices; D012542:Scattering, Radiation