LOA (Palaiseau, France)
Laboratoire d' Optique Appliquée, CNRS
LOA has played a pioneering role in the development of ultrafast laser-matter science at high intensities and related new concept of ultrafast lasers and secondary sources (electrons, protons, EUV, X-ray and gamma-rays, THz). LOA was one of the founders of the Laserlab-Europe community. LOA develops cutting-edge advanced programs to answer scientific and societal challenges.
Website: loa.ensta.fr

Research highlights
Electron acceleration
LOA is now able to produce routinely kHz electron beams in the 5-10 MeV range, see latest results in Monzac et al. Phys. Rev. Research 6 043099 (2024). In addition, cutting-edge experiments have shown the effect of the CEP in electron acceleration driven by near-single cycle pulses: Huijts et al., PRX 12, 01136 (2022).
Relativistic X-ray emission
We demonstrated a simple method to enhance the energy and the flux of Betatron sources without increasing the laser energy. The orbits of the relativistic electrons emitting the radiation were controlled using density tailored plasmas. [Phys. Rev. X 10, 011061 (2020)]
Soft X-ray laser
Using a ptychographic approach, we were able to reconstruct the complex wavefront of the seeded soft X-ray laser wave. Its shows an excellent agreement with extensive 3D Maxwell-Bloch calculations. The soft X-ray laser was strongly focused on a Ti foil and generated its second harmonic. [Arxiv physics.optics, arXiv:2009.05151]
Lasing in air
A cavity-free laser in the sky could lead to revolutionary improvements in optical remote sensing for atmospheric science. Intense forward emission around 391 or 428 nm with energy up to several microjoules was observed during filamentation of femtosecond laser pulses in atmosphere. [Phys. Rev. Lett. 123, 243203 (2019)]
High NA EUV wavefront sensing
A new EUV wavefront sensor with numerical aperture up to 0.19 has been developed at LOA [Optics Letters, 45, 1, 4248, (2020)]. It has been successfully tested at FLASH free-electron laser with the alignment of a Schwarzschild microscope as well as internally for measuring the wavefront of harmonics from solid. This is an important step towards EUV sensors dedicated to EUV lithography. [sensors 2020, 20, 6426; doi:10.3390/s20226426]
Expertise
The LOA develops ultra-short and intense laser aiming at developing ultrafast laser-matter science at high intensities and related new concepts of secondary sources (electrons, protons, EUV, X-ray and gamma-rays, THz).
The laboratory covers 7 research areas.
- Production of the shortest duration laser pulses to provide the highest laser intensity with table-top, high repetition-rate laser systems to drive relativistic-intensity laser-plasma and attosecond science.
- Study of fundamental aspects of laser-plasma interaction in the relativistic regime to develop compact particle accelerators.
- Generation of ultrafast X-ray sources from laser-produced plasma or laser-driven electron beams.
- Pulsed radiolysis using ultrafast laser-driven electron or X-ray beams.
- Non-linear propagation of ultra-short lasers in transparent media like in air.
- High-resolution imaging taking advantages of the compactness, small source size and short pulse duration of the secondary sources (electron, EUV, X-rays and gamma-rays)
- Ultrafast solid-state physics and femto-magnetism.
Services for industry
Lasers
Ultrashort laser pulse amplification, compression and metrology: Expertise inthe development of few-cycle lasers
Medicine
Cancer diagnostic and treatment: Expertise in X-ray imaging and electron therapy
lnteraction laser-matter
Laser guiding: Expertise in applications based on laser guiding (e.g. lightning guiding)
Equipment offered to external users
Our research infrastructures lie in one site located at the ENSTA-Yvette research centre where experimental sites and offices are spread over a total surface of 5200 m2. LOA provides uniqueness instrumentations in the field of ultrafast laser-plasmas with laser duration down to an optical cycle & high repetition-rate, multi-beams synchronized at the femtosecond time-scale (up to 5 in Salle Jaune for example), dedicated topics and fixed experimental set-up.
Name | Energy | Duration (fs) |
Peak intensity (Wcm-2) |
Repetition rate (Hz) |
Experimental area | Topics |
Salle Jaune | 2x2J + probe beams + 0.5J / 500 ps beam |
30 | ≥ 5×1020 | 10 | 3 fully equipped beamlines in radioprotected environment | • Electron acceleration • Ultrafast relativistic X-rays • Soft X-ray laser • Application of secondary sources |
Salle Corail / Argent | 3 mJ | 40 | 5×1017 | 5,000 | 5 fully equipped beamlines | • High harmonic generation • EUV metrology • Femtosecond electron spectroscopy • Ultrafast solid-state physics • THz • Femtomagnetism |
Salle Noire 2.0 |
4 mJ | ≤ 4 | 5×1018 | 1,000 | 1 versatile experimental chamber | • High harmonics from solid • Electron acceleration • Non-linear physics |
Salle Violette | 200 mJ | 50 | 1.5×1018 | 100 | 1 versatile site | • Lasing in air • Laser-driven acoustic wave • Electrical discharge triggered by laser |