Communication Dans Un Congrès Année : 2025

Extreme ultraviolet source based on high harmonic generation in solids with a high-energy fiber-based 1550 nm driving laser

Angela Vella

Résumé

High harmonic generation (HHG) is a well-established process used to produce light in the extreme ultraviolet (EUV) range. EUV sources hold significant potential for applications in ultrafast spectroscopy, lithography, and atom probe tomography. High harmonics of the driving laser frequency can be generated by tightly focusing a high-energy laser into a nonlinear medium, such as a gas, solid, or plasma. Historically, HHG has been primarily driven by lasers with wavelengths around 800 nm. However, mid-infrared (mid- IR) lasers have gained increasing interest due to their ability to extend the harmonic cutoff, enabled by the quadratic wavelength scaling of the ponderomotive energy [1]. Additionally, mid-IR drivers offer improved damage thresholds, making them attractive for high-intensity applications. Optical Parametric Chirped-Pulse Amplification (OPCPA) and Optical Parametric Amplifier (OPA) systems have proven effective in achieving these results, but their inherent complexity highlights the need for more compact, efficient, and scalable EUV generation techniques [1, 2, 3]. In this context, ultrafast mid- IR fiber lasers have emerged as a promising alternative for HHG. However, their pulse energies remain limited to the nanojoule range, posing a challenge for generating high-flux EUV radiation [4]. In this work, we demonstrate high-order harmonic generation in bulk crystals using a high-energy fiber laser system operating near 1550 nm. The system delivers few-cycle pulses with durations below 50 fs, microjoule- level pulse energies, and a repetition rate of 660 kHz. This is achieved by combining a high-energy chirped- pulse amplifier featuring erbium-doped fibers, initially producing 600 fs pulses, with a post-compression stage based on an Argon-filled hollow-core photonic crystal fiber (HC-PCF) [5, 6]. The interplay between anomalous dispersion and Kerr nonlinearity along the HC-PCF enables the generation of fundamental solitons with more than 18 Megawatts peak power and sub-50 fs duration. The compressed pulses are then focused into an MgO crystal to generate EUV high-order harmonics. The EUV spectra were measured using a home-built spectrometer and analyzed as a function of the crystal orientation relative to the laser polarization, and the driving laser intensity. As a result, harmonic orders up to the 31st were detected, with a total photon flux reaching 5 × 10⁶ photons per second. To conclude, we demonstrated the successful use of the high-energy fiber laser platform with a HC-PCF- based post compression stage as a driving laser for efficient HHG-based EUV source.

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Dates et versions

hal-05162062 , version 1 (15-07-2025)

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Identifiants

  • HAL Id : hal-05162062 , version 1

Citer

Anastasiia Mikhneva, Djamila Boukhaoui, Saïd Idlahcen, Jonathan Houard, Ivan Blum, et al.. Extreme ultraviolet source based on high harmonic generation in solids with a high-energy fiber-based 1550 nm driving laser. Réunion Plénière du GDR UP, GDR UP, Mar 2025, Paris, France. ⟨hal-05162062⟩
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