New approaches to light control: From nonlinear quasi-waveguides to gas-phase sono-photonics

Ultrafast optical laser pulses play a crucial role in many fields: they enable precise measurements on the nanometre length and on femtosecond to attosecond time scales, and are essential for many industrial applications such as semiconductor manufacturing and healthcare.
Although ultrafast lasers have been available for more than half a century, our ability to generate and control ultrashort pulses is still advancing rapidly. This talk will focus on two new laser pulse control schemes.
The first scheme relies on optical multi-pass cells (MPCs), powerful tools for nonlinear optics with quasi-waveguiding properties that hybridise free-space and guided-wave nonlinear optics [1]. MPCs have enabled large-factor post-compression of ultrashort pulses approaching the few-cycle regime [2]. Complementing fibre-based nonlinear optical approaches, they offer exciting possibilities for advanced frequency conversion that go well beyond post-compression [3].
The second scheme uses intense ultrasound (sono) waves for contactless laser pulse (photon) control directly in ambient air, opening a new field of research: gas-phase sono-photonics [4]. Recently, gas-phase sono-photonic light control has made it possible to push the peak power limit of acousto-optic modulators by about three orders of magnitude, while opening up new degrees of freedom for programmable laser pulse control at exotic wavelengths.

1. A.-L. Viotti, M. Seidel, E. Escoto, [...], C.M. Heyl, “Multi-pass cells for post-compression of ultrashort laser pulses”, Optica 9, 197-216 (2022).
2. S. Rajhans […], C.M.Heyl, “Post-compression of multi-millijoule picosecond pulses to few-cycles approaching the terawatt regime”, Opt. Lett. 48, 18 (2023).
3. P. Balla, H. Tünnermann, S.H. Salman, [...], C.M. Heyl, “Ultrafast serrodyne optical frequency translator”, Nature Photonics 17, 187–192 (2023).
4. Y. Schrödel, C. Hartmann, C. Zheng, [...], Heyl, C.M., “Acousto-optic modulation of gigawatt-scale laser pulses in ambient air”, Nature Photonics 18, 54–59 (2024).