An intense, few-cycle source in the long-wave infrared

Abstract

For the last several decades, the wavelength range accessible for strong-field, few-cycle studies has remained limited to the visible, near infrared and mid-wave infrared regimes. In particular, sources in the long-wave infrared have been lacking. We report the development of a 1 kHz, few-cycle laser source with up to a 9 μ m central wavelength and gigawatt peak powers. When focused, this source can ionize gas targets, which we demonstrate here through the ionization of atomic xenon at wavelengths ranging from 5 μ m to 9 μ m. This opens up new opportunities for fundamental atomic and molecular physics, enabling experimental tests of strong-field ionization theories in the extreme long-wavelength, few-cycle limit and the direct excitation of vibrational transitions in organic molecules.

Decadal bandwidth phase matching for frequency resolved optical gating from the near to the long wavelength infrared

“…Considering the broad use of the SHG-FROG and X-FROG techniques and the limitation of the crystals they rely on, it would be beneficial to have access to a crystal which has an extremely broad transparency window, can phase match all of the required processes in this window, and which has phase matching bandwidth that spans this window. For this reason, as far as we are aware, there has been only three reports on the use of X-FROG for the chracterization of LWIR femtosecond pulses [8,9,10]. Here we report on results which show poly-crystalline Zinc Selenide (pc-ZnSe) meets all these requirements due to its large transmission window and random quasi-phase-matching properties [11,12].…”

“…Often X-FROG is used to characterize a pulse whose second-harmonic isn't measurable with commonly used silicon based spectrometers. For example in [8] we demonstrated an X-FROG measurement of a femtosecond long-wavelength infrared (LWIR, 7-14 µm) pulse using a gate pulse that was ten times shorter in wavelength. In both FROG and X-FROG, the nonlinear crystal being used needs to be transmissive for all wavelengths involved, have a phase-matching orientation to allow for generation of the second-harmonic or sum-frequency, and be thin enough to provide for sufficient phase-matching bandwidth of the nonlinear process.…”

Ultrashort-pulse, terawatt, long-wave infrared lasers based on high-pressure CO2amplifiers

“…Extending the wavelength range covered by high-peakpower laser systems into the mid-wave-and long-wave infrared (MWIR and LWIR respectively) promises many advantages for high-energy physics and material research [1]. Some examples of applications that can benefit from increasing the laser wavelength are the laser wakefield acceleration of electrons, the laser acceleration of ions from gas targets, and the generation of highenergy, supercontinuum, attosecond pulses.…”

Asymmetric high energy dual optical parametric amplifier for parametric processes and waveform synthesis

“…As an example, interest in ultrafast laser sources in the mid infrarad (MIR) to long wavelength infrared (LWIR) has grown substantially due to the applications these wavelengths provide in the molecular fingerprint region, including studies on vibrationally mediated photochemistry [1], infrared chemical nano-imaging [2], coherent control of vibrational dynamics [3], and femtochemistry [4]. Producing ultrafast infrared pulses capable of strong field studies is still an ongoing endeavor [5][6][7], with one of the first examples of strong field ionization of a noble gas in the LWIR being shown only recently [5]. Furthermore, the need for ultra-fast pulses beyond 20 𝜇m has grown in recent decades for strong interactions with quantum materials [8][9][10].…”