A technique for optically accessing ultra-high vacuum environments, via a photonic-crystal fiber with a long small hollow core, is described. The small core and the long bore enable a pressure ratio of over 10(8) to be maintained between two environments, while permitting efficient and unimpeded delivery of light, including ultrashort optical pulses. This delivery can be either passive or can encompass nonlinear optical processes such as optical pulse compression, deep UV generation, supercontinuum generation, or other useful phenomena. (C) 2013 AIP Publishing LLC.
PHz-wide Supercontinua of Nondispersing Subcycle Pulses Generated by
Extreme Modulational Instability
Modulational instability (MI) of 500 fs, 5 mu J pulses, propagating in gas-filled hollow-core kagome photonic crystal fiber, is studied numerically and experimentally. By tuning the pressure and launched energy, we control the duration of the pulses emerging as a consequence of MI and hence are able to study two regimes: the classical MI case leading to few-cycle solitons of the nonlinear Schrodinger equation; and an extreme case leading to the formation of nondispersing subcycle pulses (0.5 to 2 fs) with peak intensities of order 10(14) Wcm(-2). Insight into the two regimes is obtained using a novel statistical analysis of the soliton parameters. Numerical simulations and experimental measurements show that, when a train of these pulses is generated, strong ionization of the gas occurs. This extreme MI is used to experimentally generate a high energy (> 1 mu J) and spectrally broad supercontinuum extending from the deep ultraviolet (320 nm) to the infrared (1300 nm).
Contact
Research Group Francesco Tani
Max Planck Institute for the Science of Light Staudtstr. 2 91058 Erlangen, Germany
