Deep ultraviolet supercontinuum generation in optical nanofibers by femtosecond-pulses at 400 nm wavelength
Date
2010
Authors
Heidt A.M.
Hartung A.
Bartelt H.
Journal Title
Journal ISSN
Volume Title
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Abstract
Freestanding nanofibers with submicron diameter exhibit a strong waveguide dispersion and field localization caused by both the extreme small core diameter compared to common optical standard fibers and the large refractive index difference of Δn = 0.45 between the silica core and air cladding. These are promising characteristics for nonlinear applications like e.g. supercontinuum generation that require waveguides with large nonlinear coefficients and specific dispersion behavior in dependence on the pump wavelength. Optical nanofibers allow a shift of the zero dispersion wavelength and in addition anomalous dispersion down to a wavelength of about 460 nm. We report on deep ultraviolet broadband supercontinuum generation in optical nanofibers pumped with femtosecond pulses from a frequency doubled titan-sapphire oscillator at 400nm wavelength. Numerical simulations of the generated spectra show a remarkable broadening in the deep ultraviolet wavelength range below 250 nm after only a few millimeter of propagation distance, while a single recompressible pulse is maintained in the time domain. The spectrum can be influenced by nanofiber diameter, pulse duration, and pulse energy. In experiment these nanofibers are situated in an optical fiber taper configuration where a waist of constant submicron diameter is located between two taper transitions with varying diameter. For this reason the generated supercontinuum is not only influenced by the nanofiber diameter but by the taper transitions. © 2010 SPIE.
Description
Keywords
Air cladding, Anomalous dispersion, Core diameters, Deep ultraviolet, Dispersion behavior, Femtosecond pulse, Femtosecond pulses, Femtoseconds, Field localization, Nonlinear applications, Nonlinear coefficient, Numerical simulation, Optical fiber tapers, Optical standards, Propagation distances, Pulse durations, Pulse energies, Pump wavelength, Sapphire oscillators, Silica cores, Submicron diameters, Supercontinuum, Supercontinuum generations, Time domain, Waveguide dispersions, Zero-dispersion wavelength, Computer simulation, Crystal whiskers, Dispersion (waves), Dispersions, Electromagnetic pulse, Fibers, Nanofibers, Optical fibers, Optical pumping, Photonic crystal fibers, Photonic crystals, Refractive index, Silica, Ultrashort pulses, Waveguides, Wavelength, Pulse generators
Citation
Proceedings of SPIE - The International Society for Optical Engineering
7714
7714