Tunable quantum dots in monolithic Fabry-Perot microcavities for high-performance single-photon sources

Cavity-enhanced single quantum dots(QDs)are the main approach towards ultra-high-performance solid-state quantum light sources for scalable photonic quantum technologies.Nevertheless,harnessing the Purcell effect requires precise spectral and spatial alignment of the QDs’emission with the cavity mode,which is challenging for most cavities.Here we have successfully integrated miniaturized Fabry-Perot microcavities with a piezoelectric actuator,and demonstrated a bright single-photon source derived from a deterministically coupled QD within this microcavity.Leveraging the cavity-membrane structures,we have achieved large spectral tunability via strain tuning.On resonance,a high Purcell factor of~9 is attained.The source delivers single photons with simultaneous high extraction efficiency of 0.58,high purity of 0.956(2)and high indistinguishability of 0.922(4).Together with its compact footprint,our scheme facilitates the scalable integration of indistinguishable quantum light sources on-chip,therefore removing a major barrier to the development of solid-state quantum information platforms based on QDs.

Ultra-low threshold continuous-wave quantum dot mini-BIC lasers

Highly compact lasers with ultra-low threshold and single-mode continuous wave(CW)operation have been a long sought-after component for photonic integrated circuits(PICs).Photonic bound states in the continuum(BICs),due to their excellent ability of trapping light and enhancing light-matter interaction,have been investigated in lasing configurations combining various BIC cavities and optical gain materials.However,the realization of BIC laser with a highly compact size and an ultra-low CW threshold has remained elusive.We demonstrate room temperature CW BIC lasers in the 1310 nm O-band wavelength range,by fabricating a miniaturized BIC cavity in an InAs/GaAs epitaxial quantum dot(QD)gain membrane.By enabling effective trapping of both light and carriers in all three dimensions,ultra-low threshold of 12μW(0.052 kW cm^(-2))is achieved at room temperature.Single-mode lasing is also realized in cavities as small as only 5×5 unit cells(~2.5×2.5μm^(2) cavity size)with a mode volume of 1.16(λ/n)^(3).The maximum operation temperature reaches 70℃ with a characteristic temperature of T_(0)~93.9 K.With its advantages in terms of a small footprint,ultra-low power consumption,and adaptability for integration,the mini-BIC lasers offer a perspective light source for future PICs aimed at high-capacity optical communications,sensing and quantum information.

Filter-free high-performance single-photon emission from a quantum dot in a Fabry–Perot microcavity

Combining resonant excitation with Purcell-enhanced single quantum dots(QDs)stands out as a prominent strategy for realizing high-performance solid-state single-photon sources.However,optimizing photon extraction efficiency requires addressing the challenge of effectively separating the excitation laser from the QDs’emission.Traditionally,this involves polarization filtering,limiting the achievable polarization directions and the scalability of polarized photonic states.In this study,we have successfully tackled this challenge by employing spatially orthogonal resonant excitation of QDs,deterministically coupled to monolithic Fabry–Perot microcavities.Leveraging the planar microcavity structure,we have achieved spectral filter-free single-photon resonant fluorescence.The resulting source produces single photons with a high extraction efficiency of 0.87 and an indistinguishability of 0.963(4).

Rapunzel综合征一例

患者,女性,16岁,主因“间断腹胀、腹痛不适4月余,加重2天”于2017年3月23日入院。患者于4月前因进食自己的头发、指甲后开始逐渐出现上腹胀痛不适,进食后症状加重,可自行缓解,无发热、恶心、呕吐等不适,就诊于当地医院给予对症治疗后症状好转。2天前患者腹胀、腹痛症状加重,并出现恶心、呕吐,在当地医院行电子胃镜检查,提示胃内可见巨大发丝团块,充满胃腔。为求手术治疗收住空军特色医学中心普通外科。