Presentation Information
[11p-B11-7]Self-aligned heterogeneous quantum photonic integration
Kinfung Ngan1, Yeeun Choi2, Chun-Chieh Chang3, 〇DONGYEON KANG2, Shuo Sun1 (1.University of Colorado Boulder, USA, 2.KIST, Korea, 3.Los Alamos National Laboratory, USA)
Keywords:
Quantum memory,Photonic crystal,Hybrid Integration
Introduction
Scaling quantum communication, quantum networks, and photonic quantum information processing requires low-loss circuits that generate, control, and detect single photons on chip. Group-IV color centers in diamond are promising spin-photon interfaces, but large-scale diamond photonic circuits remain difficult to fabricate. Heterogeneous integration with mature thin-film materials such as Si, SiN, LiNbO3, and TiO2 is therefore essential. Conventional methods suffer from scattering, dB-level insertion loss, alignment errors, and material restrictions.Method
We propose a self-aligned heterogeneous integration method. An inverse photonic circuit pattern is formed in electron-beam resist on SiO2, and a single-crystal diamond nanobeam is inserted into a funnel-shaped slot. The slot geometry constrains lateral and angular motion, enabling self-aligned positioning. TiO2 is then conformally deposited, etched back, and the resist is removed, embedding the nanobeam in the TiO2 circuit.Results
Nanobeam insertion succeeded for 31 device slots, and crack-protected devices survived later processing. The diamond and TiO2 interface showed well-matched modes near 737 nm, with calculated insertion loss below 0.8 percent and measured free-space scattering loss below 1.3 percent. A diamond and TiO2 fishbone photonic crystal cavity reached Q = 4600. When tuned to a SiV zero-phonon line, emission increased by 6.1 times and lifetime shortened from 1.78 ns to 1.08 ns, indicating Purcell enhancement with FP = 3.7. Optical linewidths remained comparable to bulk diamond, with spin initialization fidelity of 0.72 and T1 of 130 ns. An inverse-designed extractor was predicted to reach 84 percent collection efficiency.Conclusion
This approach enables low-loss integration of solid-state quantum emitters with thin-film photonics, supporting scalable quantum networks and integrated quantum light sources.
Scaling quantum communication, quantum networks, and photonic quantum information processing requires low-loss circuits that generate, control, and detect single photons on chip. Group-IV color centers in diamond are promising spin-photon interfaces, but large-scale diamond photonic circuits remain difficult to fabricate. Heterogeneous integration with mature thin-film materials such as Si, SiN, LiNbO3, and TiO2 is therefore essential. Conventional methods suffer from scattering, dB-level insertion loss, alignment errors, and material restrictions.Method
We propose a self-aligned heterogeneous integration method. An inverse photonic circuit pattern is formed in electron-beam resist on SiO2, and a single-crystal diamond nanobeam is inserted into a funnel-shaped slot. The slot geometry constrains lateral and angular motion, enabling self-aligned positioning. TiO2 is then conformally deposited, etched back, and the resist is removed, embedding the nanobeam in the TiO2 circuit.Results
Nanobeam insertion succeeded for 31 device slots, and crack-protected devices survived later processing. The diamond and TiO2 interface showed well-matched modes near 737 nm, with calculated insertion loss below 0.8 percent and measured free-space scattering loss below 1.3 percent. A diamond and TiO2 fishbone photonic crystal cavity reached Q = 4600. When tuned to a SiV zero-phonon line, emission increased by 6.1 times and lifetime shortened from 1.78 ns to 1.08 ns, indicating Purcell enhancement with FP = 3.7. Optical linewidths remained comparable to bulk diamond, with spin initialization fidelity of 0.72 and T1 of 130 ns. An inverse-designed extractor was predicted to reach 84 percent collection efficiency.Conclusion
This approach enables low-loss integration of solid-state quantum emitters with thin-film photonics, supporting scalable quantum networks and integrated quantum light sources.