Long-lived refractive index changes induced by femtosecond ionization in gas-filled single-ring photonic crystal fibers

Abstract

We investigate refractive index changes caused by femtosecond photoionization in a gas-filled hollow-core photonic crystal fiber. Using spatially-resolved interferometric side-probing, we find that these changes live for tens of microseconds after the photoionization event - eight orders of magnitude longer than the pulse duration. Oscillations in the megahertz frequency range are simultaneously observed, caused by mechanical vibrations of the thin-walled capillaries surrounding the hollow core. These two non-local effects can affect the propagation of a second pulse that arrives within their lifetime, which works out to repetition rates of tens of kilohertz. Filling the fiber with an atomically lighter gas significantly reduces ionization, lessening the strength of the refractive index changes. The results will be important for understanding the dynamics of gas-based fiber systems operating at high intensities and high repetition rates, when temporally non-local interactions between successive laser pulses become relevant.

arXiv comment5 pages with four figures and one table

References in corpus (4)

• Generation of micro-J pulses in the deep UV at MHz repetition rates
• Extreme Nonlinear Optics in a Femtosecond Enhancement Cavity
• Novel mid-infrared dispersive wave generation in gas-filled PCF by transient ionization-driven changes in dispersion
• Direct measurement of the acoustic waves generated by femtosecond filaments in air

Cited by in corpus (8)

• Efficient single-cycle pulse compression of an ytterbium fiber laser at 10 MHz repetition rate
• Efficient and compact source of tuneable ultrafast deep ultraviolet laser pulses at 50 kHz repetition rate
• Generation and characterization of frequency tuneable sub-15 fs pulses in a gas-filled hollow-core fiber pumped by a Yb:KGW laser
• Dispersion-tuning of nonlinear optical pulse dynamics in gas-filled hollow capillary fibers
• Pump-probe study of plasma dynamics in gas-filled photonic crystal fiber using counter-propagating solitons
• Temporal self-compression and self-frequency shift of sub-microjoule pulses at 8 MHz repetition rate
• Spatio-temporal measurement of ionization-induced modal index changes in gas-filled PCF by prism-assisted side-coupling
• Investigation of spatiotemporal output beam profile instabilities from differentially pumped capillaries