Ultrafast supercontinuum generation in gas-filled waveguides is an enabling technology for many intriguing applications ranging from attosecond metrology towards biophotonics,with the amount of spectral broadening cru...Ultrafast supercontinuum generation in gas-filled waveguides is an enabling technology for many intriguing applications ranging from attosecond metrology towards biophotonics,with the amount of spectral broadening crucially depending on the pulse dispersion of the propagating mode.In this study,we show that structural resonances in a gas-filled antiresonant hollow core optical fiber provide an additional degree of freedom in dispersion engineering,which enables the generation of more than three octaves of broadband light that ranges from deep UV wavelengths to near infrared.Our observation relies on the introduction of a geometric-induced resonance in the spectral vicinity of the ultrafast pump laser,outperforming gas dispersion and yielding a unique dispersion profile independent of core size,which is highly relevant for scaling input powers.Using a krypton-filled fiber,we observe spectral broadening from 200 nm to 1.7μm at an output energy of B 23μJ within a single optical mode across the entire spectral bandwidth.Simulations show that the frequency generation results from an accelerated fission process of solitonlike waveforms in a non-adiabatic dispersion regime associated with the emission of multiple phase-matched Cherenkov radiations on both sides of the resonance.This effect,along with the dispersion tuning and scaling capabilities of the fiber geometry,enables coherent ultra-broadband and high-energy sources,which range from the UV to the mid‐infrared spectral range.展开更多
We report on the observation of subcycle interferences of electron wave packets released during strong field ionization of H_2 with cycle-shaped two-color laser fields. With a reaction microscope we measure three-dime...We report on the observation of subcycle interferences of electron wave packets released during strong field ionization of H_2 with cycle-shaped two-color laser fields. With a reaction microscope we measure three-dimensional momentum distributions of photoelectrons correlated with either H_2^+ or protons within different energy ranges generated by dissociation of H_2^+. We refer to these different types of photoelectrons as channels. Our results show that the subcycle interference structures of electron wave packets are very sensitive to the cycle shape of the two-color laser field. We explain this behavior by the dependence of the ionization time within an optical cycle on the shape of the laser field cycle. The subcycle interference structures can be further used to obtain insight into the subcycle dynamics of molecules during strong field interaction.展开更多
基金the federal state of Thuringia(FKZ:2012FGR0013 and FKZ:2016FGR0051)support from the Humboldt Foundation.R.S.acknowledges support from German Research Foundation(DFG)for funding through International Research Training Group(IRTG)2101support from German Research Foundation(DFG)via the project SCHM2655/3-1.
文摘Ultrafast supercontinuum generation in gas-filled waveguides is an enabling technology for many intriguing applications ranging from attosecond metrology towards biophotonics,with the amount of spectral broadening crucially depending on the pulse dispersion of the propagating mode.In this study,we show that structural resonances in a gas-filled antiresonant hollow core optical fiber provide an additional degree of freedom in dispersion engineering,which enables the generation of more than three octaves of broadband light that ranges from deep UV wavelengths to near infrared.Our observation relies on the introduction of a geometric-induced resonance in the spectral vicinity of the ultrafast pump laser,outperforming gas dispersion and yielding a unique dispersion profile independent of core size,which is highly relevant for scaling input powers.Using a krypton-filled fiber,we observe spectral broadening from 200 nm to 1.7μm at an output energy of B 23μJ within a single optical mode across the entire spectral bandwidth.Simulations show that the frequency generation results from an accelerated fission process of solitonlike waveforms in a non-adiabatic dispersion regime associated with the emission of multiple phase-matched Cherenkov radiations on both sides of the resonance.This effect,along with the dispersion tuning and scaling capabilities of the fiber geometry,enables coherent ultra-broadband and high-energy sources,which range from the UV to the mid‐infrared spectral range.
基金financed by the Austrian Science Fund(FWF)under grants P25615-N27,P28475-N27,P21463N22,P27491-N27 and SFB-F49 NEXTliteby a starting grant from the European Research Council(ERC project CyFi)
文摘We report on the observation of subcycle interferences of electron wave packets released during strong field ionization of H_2 with cycle-shaped two-color laser fields. With a reaction microscope we measure three-dimensional momentum distributions of photoelectrons correlated with either H_2^+ or protons within different energy ranges generated by dissociation of H_2^+. We refer to these different types of photoelectrons as channels. Our results show that the subcycle interference structures of electron wave packets are very sensitive to the cycle shape of the two-color laser field. We explain this behavior by the dependence of the ionization time within an optical cycle on the shape of the laser field cycle. The subcycle interference structures can be further used to obtain insight into the subcycle dynamics of molecules during strong field interaction.
