集成电信稀土光子平台中的毫秒级光学相干性与强集体耦合
Millisecond optical coherence and strong collective coupling in an integrated telecom rare-earth photonic platform
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中文总结 AI 辅助
本研究将相干性优化的Er³⁺:CaWO₄晶体无粘合剂键合到电光可调薄膜铌酸锂微环谐振器，实现了电信波长下的强集体耦合、毫秒级相干性与原位光谱调谐，为可扩展电信量子网络提供了异质集成方案。
中文摘要 AI 辅助
长距离量子网络节点需要在电信波长下同时具备强光-物质耦合、长相干时间和原位光谱调控能力。集成器件中铒（Er）的相干性受限于其基质，这些基质无法同时提供相干性优化的块状晶体中存在的弱磁性核自旋环境和明确的取代位点。本研究通过将Er³⁺:CaWO₄基质无粘合剂键合至高Q电光可调薄膜铌酸锂微环谐振器，将这种优化晶体集成到光子芯片上。在75 mK的有效温度和仅0.2 T的磁场下，键合的铒系综保持了289±34 Hz的有效均匀线宽（T_M=1.10±0.13 ms），光谱扩散速率为86±18 Hz，饱和值为1.5±0.2 kHz。通过电光调谐谐振器穿过铒的光学跃迁，可分辨出集体协同性C=6.7±0.4的避免交叉。利用与基质¹⁸³W核自旋的超超精细耦合，研究人员实现了光学相位信息的存储与读取，存储时长为5 s，可见度为0.935±0.015。因此，单器件中实现的强集体耦合、毫秒级相干性和原位光谱调谐，确立了利用相干性优化基质的异质集成作为可扩展电信量子网络的实现路径。
英文摘要
Long-range quantum network nodes require the combination of strong light-matter coupling, long coherence times and in situ spectral control at telecom wavelengths. The coherence of erbium in integrated devices is held back by its hosts, which do not simultaneously provide the weakly magnetic nuclear-spin environment and the well-defined substitutional sites found in coherence-optimised bulk crystals. Here we bring such an optimised crystal onto a photonic chip, by bonding an Er${^{3+}}$:CaWO${_{4}}$ host without an adhesive interlayer to a high-${Q}$ electro-optically tuneable thin-film lithium niobate microring resonator. At an effective temperature of ${75}$ mK and a field of only ${0.2}$ T, the bonded ensemble retains an effective homogeneous linewidth of ${289\pm34}$ Hz (${T_\text{M}=1.10\pm0.13}$ ms), with spectral diffusion proceeding at ${86\pm18}$ Hz and saturating at ${1.5\pm0.2}$ kHz. Electro-optically tuning the resonator through the erbium optical transition resolves an avoided crossing with a collective cooperativity of ${C=6.7\pm0.4}$. Exploiting superhyperfine coupling to the host's ${^{183}}$W nuclear spins, we store and retrieve optical phase information over ${5}$ s with a visibility of ${0.935\pm0.015}$. Strong collective coupling, millisecond coherence and in situ spectral tuning in a single device thus establish heterogeneous integration leveraging coherence-optimised hosts as a route to scalable telecom quantum networks.
