Toward terawatt few-cycle pulses via optical parametric chirped-pulse amplification with oxide crystals

Abstract

High-power femtosecond lasers beyond $5~\unicode[STIX]{x03BC}\text{m}$ are attractive for strong-field physics with mid-infrared (IR) fields but are difficult to scale up. In optical parametric chirped-pulse amplification (OPCPA) at mid-IR wavelengths, a nonlinear crystal is vital, and its transmittance, dispersion, nonlinear coefficient and size determine the achievable power and wavelength. OPCPA beyond $5~\unicode[STIX]{x03BC}\text{m}$ routinely relies on semiconductor crystals because common oxide crystals are not transparent in this spectral range. However, the small size and low damage threshold of semiconductor crystals fundamentally limit the peak power to gigawatts. In this paper, we design a terawatt-class OPCPA system at $5.2~\unicode[STIX]{x03BC}\text{m}$ based on a new kind of oxide crystal of $\text{La}_{3}\text{Ga}_{5.5}\text{Nb}_{0.5}\text{O}_{14}$ (LGN). The extended transparent range, high damage threshold, superior phase-matching characteristics and large size of LGN enable the generation of 0.13 TW seven-cycle pulses at $5.2~\unicode[STIX]{x03BC}\text{m}$ . This design fully relies on the state-of-the-art OPCPA technology of an octave-spanning ultrafast Ti:sapphire laser and a thin-disk Yb:YAG laser, offering the performance characteristics of high power, a high repetition rate and a stable carrier–envelope phase.

Birefringence Dispersion Management of Langasite Nonlinear Crystals for the Improvement of Mid-Infrared Amplification

“…OPA is the primary quadratic nonlinear process in the OPCPA system . For evaluating the OPCPA performance of the LGNT x solid-solution crystals, the relationships between the PM angles and the idler wavelengths corresponding to the Type I (1/λ 3 e = 1/λ 1 o + 1/λ 2 e ) and Type II (1/λ 3 o = 1/λ 1 o + 1/λ 2 e ) , OPA are determined and presented in Figure .…”

“…Mid-infrared (mid-IR) ultrashort and ultra-intense coherent light sources hold the advantages of long wavelength and high-peak power and are fundamental for the development of various fields of high-power physics, including particle acceleration, attosecond pulses, and ultrafast coherent X-rays . To date, the optical parametric chirped-pulse amplification (OPCPA) is one of the few highly effective ways to realize the mid-IR ultrashort and ultra-intense lasers, wherein the suitable mid-IR nonlinear optical (NLO) crystal with high damage thresholds and transmission spectral ranges is critical but few, besides the favorable effective nonlinear coefficients. , Recently, langasite crystals were identified as the candidate for the mid-IR OPCPA because of their reduced second-order phonon absorption by 2-fold rotation symmetry of (DO 4 ) tetrahedron, and among them, the La 3 Nb 0.5 Ga 5.5 O 14 (LGN) crystal was proposed to be the favorable nonlinear material , that possesses a wider transmission range (0.28–7.4 μm) than traditional oxide NLO crystals (such as the commonly applied LiNbO 3 and KTiOAsO 4 ) , due to the relatively low phonon frequency and high laser damage threshold (LDT) (1.41 GW@1.064 μm@10 ns) resulting from its large bandgap. , Meanwhile, the LGN crystal is also feasible to be directly pumped by the commercial and well-developed near-infrared lasers to achieve the mid-IR laser output . An OPCPA system based on the LGN crystal with favorable characteristics of 5.2 μm, 130 GW, and 120 fs pulses has been theoretically designed, and a tunable seed pulse ranging from 3 to 7 μm has been achieved .…”

“…10,11 Meanwhile, the LGN crystal is also feasible to be directly pumped by the commercial and well-developed near-infrared lasers to achieve the mid-IR laser output. 6 An OPCPA system based on the LGN crystal with favorable characteristics of 5.2 μm, 130 GW, and 120 fs pulses has been theoretically designed, 7 and a tunable seed pulse ranging from 3 to 7 μm has been achieved. 12 However, despite the ability to grow a large bulk, the practical application of the LGN crystal still suffers from the relatively small effective NLO coefficient d eff 12 due to the birefringence dispersion determined phase-matching conditions, which is crucial in determining the overall OPCPA performance due to the basic laser intensity dependences I ∝ d eff 2 .…”

“…To date, the optical parametric chirped-pulse amplification (OPCPA) is one of the few highly effective ways to realize the mid-IR ultrashort and ultra-intense lasers, wherein the suitable mid-IR nonlinear optical (NLO) crystal with high damage thresholds and transmission spectral ranges is critical but few, besides the favorable effective nonlinear coefficients. , Recently, langasite crystals were identified as the candidate for the mid-IR OPCPA because of their reduced second-order phonon absorption by 2-fold rotation symmetry of (DO 4 ) tetrahedron, and among them, the La 3 Nb 0.5 Ga 5.5 O 14 (LGN) crystal was proposed to be the favorable nonlinear material , that possesses a wider transmission range (0.28–7.4 μm) than traditional oxide NLO crystals (such as the commonly applied LiNbO 3 and KTiOAsO 4 ) , due to the relatively low phonon frequency and high laser damage threshold (LDT) (1.41 GW@1.064 μm@10 ns) resulting from its large bandgap. , Meanwhile, the LGN crystal is also feasible to be directly pumped by the commercial and well-developed near-infrared lasers to achieve the mid-IR laser output . An OPCPA system based on the LGN crystal with favorable characteristics of 5.2 μm, 130 GW, and 120 fs pulses has been theoretically designed, and a tunable seed pulse ranging from 3 to 7 μm has been achieved . However, despite the ability to grow a large bulk, the practical application of the LGN crystal still suffers from the relatively small effective NLO coefficient d eff due to the birefringence dispersion determined phase-matching conditions, which is crucial in determining the overall OPCPA performance due to the basic laser intensity dependences I ∝ d eff 2 …”

Table-top optical parametric chirped pulse amplifiers: past and present

“…ZnGeP 2 , ZGP) show excellent performance in the MIR with ~2 μm pumping from Ho lasers62,63 . Novel langasite oxide crystals, e.g.…”