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.
Highlights
Ultrafast light fields enable studies of ultrafast processes in physics, chemistry and biology at the femtosecond scale[1]
A precise characterization of thermal parameters for LGN crystal, e.g., temperature-dependent Sellmeier equations, is the precondition to evaluate the influence of thermal effect on the power scalability of the mid-IR optical parametric chirped-pulse amplification (OPCPA)
We have proposed a design of a 0.13 TW, seven-cycle, 5.2 μm OPCPA system based on the oxide LGN crystal
Summary
Ultrafast light fields enable studies of ultrafast processes in physics, chemistry and biology at the femtosecond scale[1]. The peak power of the 1 μm pumped OPCPA based on the semiconductor LiGaS2 crystal is significantly limited by the low damage threshold (lower than those of the langasite oxides by almost one order of magnitude) and the small available size (currently limited to 7 mm × 7 mm[43]) of LiGaS2 crystal. We design a 5.2 μm OPCPA system with LGN crystals and a commercially available 200 W, 1030 nm Yb:YAG thindisk pump laser Such a mid-IR laser source combines a 0.13 TW peak power, a seven-cycle pulse duration, a 1 kHz repetition rate and a stable carrier–envelope phase (CEP) and can find widespread applications in strong-field physics and attosecond science[50]
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