Title: Gallium Phosphide for Integrated Nonlinear Photonics
When: Friday, May 17, 2024, 11:00
Place: Department of Condensed Matter Physics, Faculty of Sciences, Module 3, Seminar Room (5th Floor)
Speaker: Konstantinos Pantzas, Centre de Nanosciences et de Nanostructures, CNRS Université Paris Saclay, France.
Gallium Phosphide is a semiconductor that is transparent above 500nm, displays strong second and third-order nonlinearities, a higher piezoelectric coefficient than other phosphides and arsenides, and is well-suited to silicon photonic integration owing to negligible lattice and thermal mismatch with silicon. The Polymétis group develops this semiconductor and its alloys to bring new functionalities to Si-photonic platforms, including optomechanic transducers [1], [2] and nonlinear photonic circuits [3].
The convergence of nonlinear optics and Silicon Photonics is of particular interest our team, as it constitutes the next step in integration, bringing the capacity NLO to convert light while preserving its quantum properties and offering a slew of new applications. Building on a unique material property of the inversion domains in GaP, the team developed a cleanroom process that allow one to periodically invert the orientation of the crystal in the plane and, thus, by design meet phase match the crystal to a target nonlinear process, and processed this orientation patterned GaP (OP-GaP) into suspended waveguides to maximize efficiency in the smallest possible footprint. Early benchmarks in collaboration with Thales RT in second harmonic generation at telecom wavelengths using this OP-GaP waveguides showed record efficiencies of 200%/Wcm2 [3], orders of magnitude higher than competing semiconductors, and showing promise to surpass even mature technologies such as LiNbO3. The talk will go over the principles and fabrication of OP-GaP and describe applications we are currently pursuing.
References
- R. Stockill et al., “Gallium Phosphide as a Piezoelectric Platform for Quantum Optomechanics,” Phys. Rev. Lett., vol. 123, no. 16, p. 163602, Oct. 2019, doi: 10.1103/PhysRevLett.123.163602.
- R. Stockill et al., “Ultra-low-noise microwave to optics conversion in gallium phosphide,” Physical Review X, 2021.
- K. Pantzas et al., “Continuous-Wave Second-Harmonic Generation in Orientation-Patterned Gallium Phosphide Waveguides at Telecom Wavelengths,” ACS Photonics, vol. 9, no. 6, pp. 2032–2039, Jun. 2022, doi: 10.1021/acsphotonics.2c00156.
