[17a-A22-1~12] KS.2 Quantum Information Engineering Group

9:00 AM - 9:15 AM JST(12:00 AM - 12:15 AM UTC)

[17a-A22-1] Dielectric Microwave-Optical Hybrid Resonator at millikelvin Temperatures

Tatsuki Hamamoto¹, Amit Bhunia¹, Rupak Bhattacharya¹, Hiroki Takahashi¹, 〇Yuimaru Kubo¹ (1.OIST)

Keywords:

Hybrid Quantum Systems,Optical Cavity,Electron Spin Resonance

Spins in solids are promising candidates for hybrid quantum systems. Some of these spins have optical transitions, expanding their applications to optically pumped maser amplifiers [1], spin-based quantum memory for optical photons [2], and spin ensemble-based quantum transducers [3], which can bi-directionally convert microwave photons and optical photons. We are developing a spin ensemble-based quantum transducer, essential for establishing a room-temperature quantum network based on superconducting qubits. We present a hybrid resonator using a dielectric material to confine the microwave mode and achieve a high internal quality factor (Qint ~ 10^4) with minimal influence from large apertures (8 mm in diameter) on the resonator housing for an optical access. Furthermore, we measured the resonator with a diamond crystal containing substitutional nitrogen impurities called P1 centers and observed strong coupling between the spin ensemble and the resonator at 10 mK [4].We used the Fabry–Pérot cavity as an optical cavity and made it as rigid as possible. The optical cavity length fluctuation can be suppressed to 18 pm in root-mean-square (r.m.s.) at 13 mK under the mechanical vibration from a dry dilution refrigerator and pulse-tube cooler [Fig. 2(b)]. This value is almost comparable to other reported values at around 4 K (Table 1). We inserted a diamond crystal into the optical cavity for hybrid quantum devices and confirmed that the cavity length fluctuation remains in the same order of magnitude (38 pm in r.m.s.).
[1] Breeze et al., Nature 555, 493–496 (2018).
[2] Khabat et al., Phys. Rev. A 89, 040301(R) (2014).
[3] Gavin et al., Phys. Rev. B 103, 214305 (2021).
[4] Hamamoto et al., Appl. Phys. Lett. [Accepted] / arXiv:2403.08458.