Development of fresnel-type solid immersion lens and bulk acoustic resonators for spin-mechanical hybrid system in diamond*

Quantum defects in solids are actively studied as promising resources in research fields such as quantum information, quantum computing, quantum networks and quantum sensing. Nanostructuring is essential to efficiently manupulate and measure defect spins, and various structures including solid immersion lens and mechanical resonators have been developed. In this presentation, we demonstrate a method for milling fresnel lens using focused ion beam, which can enhance process yield by reducing milling time (1/3 compared to hemispherical structure) while retaining high photon collection efficiency (>2 compared to flat surface). Including shallow fresnel-type lens, we further discuss the development of beam-shapred bulk acoustic resonators toward mechanical manupulation of spin states. We discuss a new design of mechanical resonator system, reflection bessel beam system, which is promissing for covering wide frequency bandwidth and high photon collection efficiency.