A scientific internship in AMOLF's Photonic Forces group studying hypersonic phonon waveguides. Phonons—quasi-particles describing sound propagation in materials—can act as carriers of quantum information, and developing nanoscale phonon waveguides that guide phonons on a chip with low loss at hypersound frequencies (~10 GHz) is highly desirable. The intern will design and fabricate nanoscale phononic crystals supporting topological edge states (inspired by the quantum spin Hall effect) and characterize them through optical experiments; achieving topological protection could enable defect-insensitive acoustic links between spin qubits for silicon quantum computing.