Near-Unity Light Collection Efficiency from Quantum Emitters in Boron Nitride by Coupling to Metallo-Dielectric Antennas
Near-Unity Light Collection Efficiency from Quantum Emitters in Boron Nitride by Coupling to Metallo-Dielectric Antennas
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DOI：
10.1021/acsnano.9b01996
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发表时间：
2019-06-01
期刊：
影响因子：
17.1
通讯作者：
Strauf, Stefan
中科院分区：
文献类型：
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作者：
Li, Xiangzhi;Scully, Robert A.;Strauf, Stefan
六方氮化硼（hBN）色心在室温条件下的明亮且稳定的单光子发射被认为是量子密码学和基于自旋的量子比特最有前途的量子光源之一，类似于金刚石中氮空位中心的最新进展。为此，需要与腔或波导模式集成以实现量子光态的理想无损转换。在这里，我们展示了一种方案，将hBN量子发射器嵌入到金属介电天线的片上阵列中，该方案提供了接近统一的光收集效率，实验值高达98%，即与裸量子发射器相比提高了7倍。在700 nm波段中的室温量子光发射的特征在于进入第一透镜的单光子发射速率在连续激发下高达44 MHz，并且在80 MHz脉冲激发（每个触发脉冲0.13个光子）下高达10 MHz，进入便于光纤对接耦合的窄输出锥（+/-15度）。我们还在此提供了在脉冲激发下的量子产率的直接测量，hBN纳米片的值为6-12%。我们所展示的方案可以在芯片上实现低损耗的自旋光子接口。
The bright and stable single-photon emission under room temperature conditions from color centers in hexagonal boron nitride (hBN) is considered as one of the most promising quantum light sources for quantum cryptography as well as spin-based qubits, similar to recent advances in nitrogen-vacancy centers in diamond. To this end, integration with cavity or waveguide modes is required to enable ideally lossless transduction of quantum light states. Here, we demonstrate a scheme to embed hBN quantum emitters into on-chip arrays of metallo-dielectric antennas that provides near unity light collection efficiencies with experimental values up to 98%, i.e. a 7-fold enhancement compared to bare quantum emitters. Room-temperature quantum light emission in the 700 nm band is characterized with single-photon emission rates into the first lens up to 44 MHz under continuous excitation and up to 10 MHz under 80 MHz pulsed excitation (0.13 photons per trigger pulse) into a narrow output cone (+/- 15 degrees) that facilitates fiber butt-coupling. We furthermore provide here a direct measurement of the quantum yield under pulsed excitation with values of 6-12% for hBN nanoflakes. Our demonstrated scheme could enable low loss spin-photon interfaces on a chip.