Ultrabright sources of single and entangled photon pairs

该项目的目标是在近红外光谱范围内制造不可区分的单光子和纠缠光子的光泵浦超亮光源，以及在红色光谱范围内制造光泵和电泵浦的单光子源。第一个目标将最终通过结合新设计的腔结构来实现，包括定位量子点(QD)、波导耦合和共振激发技术。因此，嵌入在高反射DBR结构中的InAs/GaAs量子点将以纳米精度精确地放置到微柱中。然后将锥形一维纳米线连接到这些柱子上，以实现共振侧面激发和高激光杂散光抑制。在这个方案下，我们希望建立一个非常明亮的高保真和低退相纠缠光子源。第二个目标是利用GaInP/AlGaInP材料体系实现可见红光波段的超亮电驱动单光子源。在这里，量子点，这次是InP量子点，将被嵌入到高反射DBR中，现在DBR被掺杂以允许电接触。然后，将形成具有上述精确精度的柱状结构或共振腔LED(RC-LED)台面。RC-LED将另外接收一个狭窄的氧化物孔径，以确保低电流仅流经设备中间的单个量子点。在完成这两种类型的结构之后，将可以获得具有高GHz重复频率、高收集效率和低本底的电驱动源。这些具有挑战性的目标只有通过目前世界领先的小组在制造和表征这类光子源方面的合作才能实现。特殊的关键资质是Pascale Senellart集团开发的原位光刻工艺，以及由斯图加特Peter Michler集团首创的用于共振激子和双激子制备的侧面激发技术。

The aim of this project is the fabrication of optically pumped ultrabright sources of indistinguishable single and entangled photons in the near infrared spectral range and optically and electrically pumped single photon sources in the red spectral range. The first goal will be ultimately achieved by the combination of a newly designed cavity structure including positioned quantum dots (QD), waveguide coupling and resonant excitation techniques. Therefore, InAs/GaAs quantum dots embedded in high reflective DBR structures will be precisely placed with nanometer accuracy into micropillars. Then tapered one-dimensional nanowires will be connected to these pillars to enable resonant side-excitation with a high laser stray-light suppression. With this schema, we expect to establish a very bright source of entangled photons with a high fidelity and low dephasing. The second goal will be the realization of an ultrabright electrically driven single photon source in the visible red spectral range with GaInP/AlGaInP material system. Here also quantum dots, this time InP QDs, will be embedded into high reflective DBRs, which are now doped to allow the electrical contacting. Then, either pillar structures or mesas for resonant cavity LEDs (RC-LEDs) with the above-mentioned precise accuracy will be formed. The RC-LEDs will additionally receive a narrow oxide aperture to ensure a low current flow only through the single QD in the middle of the device. After finalizing both types of structures, an electrically driven source with a high GHz repetition rate, high collection efficiency and low background will be available. These challenging goals can only be realized by the present cooperation of the world leading groups in the fabrication and characterization of these kind of photon sources. Special key qualifications are the in-situ lithography process developed in Pascale Senellarts group and the side-excitation technique for resonant exciton and biexciton preparation pioneered by Peter Michlers group in Stuttgart.