Pulse combination and compression in hollow-core fiber for few-cycle intense mid-infrared laser generation

Abstract

The generation of high-peak-power, few-cycle mid-infrared (MIR) pulses using coherent beam combination and nonlinear pulse compression techniques simultaneously is demonstrated. The two pulses, with identical pulse energy of 2.8 mJ and pulse duration of 160 fs, are coherently combined at the input end of a krypton-filled hollow-core fiber (HCF), and then the bandwidth of the combined pulse is broadened to near an optical octave due to strong phase modulations, and the temporal width is compressed into a few-cycle regime. Finally, a 2.7 mJ, 22.9 fs, 20 Hz laser at 4 μm can be obtained, and the pulse peak power is greatly enhanced compared with that of conventional single-channel optical parametric chirped pulse-amplification systems. Furthermore, the peak power generated from this system has the prospect of further scaling up through use of more channels of coherent combination, which can pave a way to generate higher peak power ultra-intense MIR pulses for strong-field physics.

Intense ultraviolet–visible–infrared full-spectrum laser

“…A silver concave mirror is used to collimate the output beam for the next measurements. At this step, a high-peak-power mid-IR supercontinuum spanning from 2.8 to 4.8 μm with 1.75 mJ energy, 23 fs pulse duration (1.7 optical cycle), and 20 Hz repetition rate is delivered from the HCF setup 39 , 40 .…”

Hollow-core optical fibers: current state and development prospects

“…Among the latest achievements in using fused silica HCFs with thick walls and large hollow core diameters, it is worth mentioning the generation of pulses with several oscillation periods in the mid-IR spectrum range [102]. For this purpose, a straight HCF filled with krypton with a hollow core diameter of 1 mm and length of 2.8 m was chosen, outside which an external grating-pair compressor was placed.…”

Coherent combining of broadband pulses after free space optical parametric amplification

“…However, the inherent high levels of self-phase modulation (SPM) [4] and dispersion in long solid-state optical media limit the capabilities of broadband high energy applications. As a solution to these difficulties some clever and fruitful gas-filled hollow-core fiber post-compression CBC approaches were shown [5,6], that were able to deliver few-cycle pulses. Nevertheless, the requirement of focusing high peak power pulsed-beams into tiny glass tubes makes the energy scaling capabilities and longevity of such systems rather questionable.…”