arXiv subjects

Jan de Haan

Publications and source records attributed to Jan de Haan.

3 recordsLinked to original sources

arXiv2026

Hybrid integration of a SESAM with a silicon nitride photonic integrated circuit

The realization of high-performance femtosecond lasers on photonic integrated circuits (PICs) requires robust, low-loss coupling between a saturable absorber and a photonic waveguide. In this work, we demonstrate the hybrid integration of a semiconductor saturable absorber mirror (SESAM) with a silicon nitride (SiN) PIC by micro-assembly. This micro-assembly strategy transfers the non-linear functionality of the absorber onto the PIC. We characterize the linear and non-linear performance of an unbonded SESAM and of a SESAM bonded to inverse-tapered SiN waveguides. At 1560~nm, the bonded device shows a waveguide-coupled modulation depth of 5.2\%, a maximum reflectivity of 37.2\%, and a saturation fluence of 47~\textmu J/cm$^2$. This work demonstrates that SESAMs can be integrated directly onto silicon nitride-based PIC platforms and provides a pathway towards fully integrated, self-starting, chip-scale ultrafast lasers.

physics.optics↗

arXiv2026

Toward nanophotonic platforms for solid-state $^{229}$Th nuclear clocks

While the $^{229}$Th nuclear isomer has recently been observed and laser-excited, converting optical nuclear manipulation into a chip-scale solid-state frequency standard remains an open challenge. Here, we present a nanophotonic platform to realize an all-solid-state nuclear clock based on the low-energy isomeric transition of $^{229}$Th embedded in high-$Q$ fluoride photonic resonators. By coupling ensembles of thorium nuclei to confined optical modes, we show that resonant field build-up in the cavity can substantially enhance the nuclear excitation rate, enabling optical interrogation at practical laser intensities. We model the nuclei-photon interaction dynamics and outline a technological roadmap toward addressing this challenge, including resonator fabrication in fluoride crystals, thorium implantation, nuclear excitation with integrated lasers, and on-chip detection of vacuum-ultraviolet photons. As an initial proof of concept, we implant a crystalline fluoride whispering-gallery-mode resonator with $^{229}$Th and assess the impact of implantation-induced damage on resonator performance. Our platform leverages recent advances in materials integration and nanophotonics to chart a realistic route toward compact and scalable nuclear frequency standards.

physics.optics↗

arXiv2025

Magic running- and standing-wave optical traps for Rydberg atoms

Magic trapping of ground and Rydberg states, which equalizes the AC Stark shifts of these two levels, enables increased ground-to-Rydberg state coherence times. We measure via photon storage and retrieval how the ground-to-Rydberg state coherence depends on trap wavelength for two different traps and find different optimal wavelengths for a one-dimensional optical lattice trap and a running wave optical dipole trap. Comparison to theory reveals that this is caused by the Rydberg electron sampling different potential landscapes. The observed difference increases for higher principal quantum numbers, where the extent of the Rydberg electron wave function becomes larger than the optical lattice period. Our analysis shows that optimal magic trapping conditions depend on the trap geometry, in particular for optical lattices and tweezers.

physics.atom-ph↗