Generation of octave-spanning mid-infrared pulses from cascaded second-order nonlinear processes in a single crystal

Yanchun Yin,Andrew Chew,Yang Wang,Fengjiang Zhuang,Jie Li,Yi Wu,Xiaoming Ren,Zenghu Chang

doi:10.1038/s41598-017-11652-9

Yanchun Yin, Andrew Chew + Show 6 more

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https://doi.org/10.1038/s41598-017-11652-9

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Journal: Scientific Reports	Publication Date: Sep 11, 2017
Citations: 30	License type: open-access

Affiliation: University of Central Florida

Abstract

We report on experimental generation of a 6.8 μJ laser pulse spanning from 1.8 to 4.2 μm from cascaded second-order nonlinear processes in a 0.4-mm BiB3O6 (BIBO) crystal. The nonlinear processes are initiated by intra-pulse difference frequency generation (DFG) using spectrally broadened Ti:Sapphire spectrum, followed by optical parametric amplification (OPA) of the DFG pulse. The highest energy, 12.6 μJ, is achieved in a 0.8-mm BIBO crystal with a spectrum spanning from 1.8 to 3.5 μm. Such cascaded nonlinear processes are enabled by the broadband pump and the coincident phase matching angle of DFG and OPA. The spectrum is initiated from the DFG process and is thus expected to have passive stable carrier-envelope phase, which can be used to seed either a chirped pulse amplifier (CPA) or an optical parametric chirped pulse amplifier (OPCPA) for achieving high-energy few-cycle mid-infrared pulses. Such cascaded second-order nonlinear processes can be found in many other crystals such as KTA, which can extend wavelengths further into mid-infrared. We achieved a 0.8 μJ laser pulse spanning from 2.2 to 5.0 μm in KTA.

Highlights

Few-cycle, mJ-level, and carrier-envelope phase (CEP) stable lasers in the short-wavelength infrared to mid-wavelength infrared are of significant interest to the ultrafast community
Most few-cycle long-wavelength lasers are centered around 2 μm or below[20,21,22,23,24,25,26,27,28], which are mainly achieved by using either optical parametric chirped pulse amplification (OPCPA) or dual-chirped optical parametric amplification (DC-OPA)[29, 30] pumped by picosecond lasers
We report on experimental generation of a 6.8 μJ pulse spanning from 1.8 to 4.2 μm by utilizing cascaded second-order nonlinear processes[43, 44], which are initiated by intra-pulse difference frequency generation (DFG) in a 0.4-mm BiB3O6 (BIBO) crystal and simultaneously amplified in the same BIBO by optical parametric amplification (OPA)

Summary

Introduction

Few-cycle, mJ-level, and carrier-envelope phase (CEP) stable lasers in the short-wavelength infrared to mid-wavelength infrared are of significant interest to the ultrafast community One of such interests is to produce isolated soft/hard X-ray attosecond pulses with shorter pulse duration and sufficient photon flux. The adiabatic DFG42 has demonstrated the capabilities of octave-spanning spectrum, arbitrary pulse shaping, and compression approaching single-cycle pulse duration, the system is complex In this Report, we experimentally generated μJ-level octave-spanning mid-IR pulses with both passive-stable CEP and high efficiency by using intra-pulse DFG in a relatively simple setup. Such mid-infrared pulse can seed a Fe2+:ZnSe CPA laser[48, 49]

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Discussion

Conclusion