Abstract
High-energy phase-stable sub-cycle mid-infrared pulses can provide unique opportunities to explore phase-sensitive strong-field light–matter interactions in atoms, molecules and solids. At the mid-infrared wavelength, the Keldysh parameter could be much smaller than unity even at relatively modest laser intensities, enabling the study of the strong-field sub-cycle electron dynamics in solids without damage. Here we report a high-energy sub-cycle pulse synthesiser based on a mid-infrared optical parametric amplifier and its application to high-harmonic generation in solids. The signal and idler combined spectrum spans from 2.5 to 9.0 µm. We coherently synthesise the passively carrier-envelope phase-stable signal and idler pulses to generate 33 μJ, 0.88-cycle, multi-gigawatt pulses centred at ~4.2 μm, which is further energy scalable. The mid-infrared sub-cycle pulse is used for driving high-harmonic generation in thin silicon samples, producing harmonics up to ~19th order with a continuous spectral coverage due to the isolated emission by the sub-cycle driver.
Highlights
The Massachusetts Institute of Technology (MIT) Faculty has made this article openly available
The carrier-envelope phase (CEP) of the idler pulse is passively stabilised by a difference-frequency generation (DFG)-like parametric process between the white-light generation (WLG) signal and the pump pulses, regardless of the CEP stability of the pump
The output pulse from the mid-IR optical parametric amplifier (OPA) together with an ~10 μJ, 2.1-μm pulse split from the pump that serves as the reference beam are sent into the XFROG for the temporal characterisation
Summary
The MIT Faculty has made this article openly available. Please share how this access benefits you. Regarding to the generation of mid-IR sub-cycle pulses, four-wave mixing through filamentation in a gas[30] and a technique that cascades DFG, spectral broadening, and chirp-compensation[31] have been demonstrated The former gives low pulse energy (~0.5 μJ)[32] and limited energy scalability as well as conical emission, while the latter has unknown CEP stability due to the complex nonlinear processes involved besides the low energy (~1 μJ). In the scheme described below, the 2.1-μm pump laser itself is a passively CEP-stabilised, optical parametric chirpedpulse amplifier (OPCPA), and its pulse width is short enough to pump a white-light generation (WLG) stage and generate an octave-spanning CEP-stable signal pulse for a mid-IR OPA
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
