High harmonic generation in solids driven by sub-cycle mid-infrared pulses from laser filamentation

Fumitoshi Kumaki,Takao Fuji,Hideto Shirai,Yutaka Nomura,G Cerullo,R Li,F Kärtner,J Ogilvie,M Khalil

doi:10.1051/epjconf/201920502023

Abstract

Carrier-envelope phase (CEP) controlled subcycle mid-infrared pulses from two-color laser filamentation have been applied for high harmonic (HH) generation in a crystalline silicon membrane. The HH spectrum reaches the ultraviolet region (<300 nm), beyond the direct band gap of the silicon. The shape of the HH spectrum shows the strong dependency on the CEP of the input pulse. The complete waveform characterization of the sub-cycle driver pulse with frequency-resolved optical gating capable of CEP determination is the effective method for the studies of the sub-cycle dynamics.

Highlights

In the last few years, high harmonic generation (HHG) in solids has been actively researched in the field of ultrafast science and solid-state physics
We report the HHG in the silicon membrane driven by CEP-controlled sub-cycle MIR pulses generated through filamentation
To investigate the complex structure and CEP dependence of the HH spectrum, we numerically simulated the CEP dependence of the HH spectrum based on the optical Bloch equations generalized to the case of a two-band semiconductor [4]

Summary

Introduction

In the last few years, high harmonic generation (HHG) in solids has been actively researched in the field of ultrafast science and solid-state physics. One of the most straightforward approaches to investigate the single-cycle ultrafast phenomena like HHG is the experimental study with well-characterized single-cycle or sub-cycle pulses [1]. In the MIR experiment, the waveform dependence, namely carrier-envelope-phase (CEP) dependence, of the high-harmonic (HH) spectra has not been studied. In this contribution, we report the HHG in the silicon membrane driven by CEP-controlled sub-cycle MIR pulses generated through filamentation. CEP stable sub-cycle MIR pulses (4 μm, 8.5 fs, 360 nJ) were generated from two-color filamentation [2]. The spectrum of the HH generated from the back surface of the membrane was introduced into a spectrograph with an electron-multiplying CCD camera (SP-2358 and ProEM1600, Princeton Instruments)

Result

Conclusion