Conference Agenda

Nonlinear optics lies at the heart of classical and quantum light generation. The invention of periodic poling revolutionized nonlinear optics and its commercial applications by enabling robust quasi-phase-matching in crystals such as lithium niobate. However, reaching useful frequency conversion efficiencies requires macroscopic dimensions, effectively limiting on-chip integration with ultracompact footprints.

Here we realize a periodically poled van der Waals semiconductor (3R-MoS2). Due to its exceptional nonlinearity, we achieve macroscopic frequency conversion efficiency (0.01%-0.1%) over a microscopic thickness of only 3μm, 10−100× thinner than current systems with similar performances.

Further, we report the generation of photon pairs at telecom wavelengths via quasi-phase-matched spontaneous parametric down-conversion. This work opens the new and unexplored field of phase-matched nonlinear optics with microscopic van der Waals crystals, unlocking new applications that require simple, ultracompact technologies such as on-chip entangled photon-pair sources for integrated quantum circuitry and sensing.

Multi-pass cells, known for their efficient spectral broadening, currently face a challenge in their peak power scalability. To address this, we implemented a strategy where the input pulse was split into 8 replicas, resulting in an increased pulse energy following nonlinear compression. The used laser delivered 208 fs pulses at 1030 nm, with pulse energies reaching up to 140uJ. Using 3 calcite crystals, the input pulse was divided and passed through the MPC, achieving a spectral broadening down to a 40 fs bandwidth limit. Subsequently, the replicas were recombined using an identical set of crystals and compressed via chirped mirrors. FROG measurements revealed a duration of 43 fs. The recombination losses amounted to less than 5 % of the output energy. This method is particularly attractive and cost-effective for spectral broadening of ultrafast lasers with adjustable repetition rate.

We present a single-stage nonlinear compression of a high power, high repetition rate Yb-doped amplifier based on a gas-filled multi-pass cell (MPC). The amplifiers delivers 100 W, 570 fs pulses at 1030 nm.

At the output of the 6.15 bar Ar-filled MPC, we measure 91 W, 22.4 fs corresponding to a transmission higher than 90 % and a compression factor of 26.

In the last years, differentmethods of laser pulse post-compression have proven their efficiency. Nonlinear spectral broadening achieved when coupling an ultrafast pulse in a gas-filled multi-pass-cell (MPC) provides common pulse compression factors of 10 to 20, depending on the initial pulse duration. We report here on the compression of up to 2 mJ, 330 fs pulses of an Ytterbium (Yb) laser down to sub-20 fs (compression factor of 17), using gas-filled MPCs, at the limit of temporal pulse breakup. Numerical calculations reproducing the experiment data, and demonstrating the importance of the driver pulse profile on the shape of the broadened spectra, are discussed.