Purification of Single Photons by Temporal Heralding of Quantum Dot Sources

Abstract

Efficient, high rate photon sources with high single photon purity are essential ingredients for quantum technologies. Single photon sources based on solid state emitters such as quantum dots are very advantageous for integrated photonic circuits, but they can suffer from a high two-photon emission probability, which in cases of non-cryogenic environment cannot be spectrally filtered. Here we propose two temporal purificationby-heralding methods for using a two photon emission process to yield highly pure and efficient single photon emission, bypassing the inherent problem of spectrally overlapping bi-photon emission at elevated temperatures. We experimentally emulate their feasibility on the emission from a single nanocrystal quantum dot at room temperature, 1 arXiv:1805.00201v4 [quant-ph]

Single Photon Sources with Near Unity Collection Efficiencies by Deterministic Placement of Quantum Dots in Nanoantennas

“…This high value of g (2) (0) is a result of the measurements being mainly done near saturation where both biexciton and plasmonic emission play a role (see Supplementary Information form more details). Using the time-filtered gating technique 38,41,42 we confirm that the emitter is indeed a single QD by measuring the second order coherence starting from various times (T F ) after the excitation pulse. This helps in differentiating between the emission of bi-excitons (which have shorter lifetime) and the emission of multiple QDs.…”

“…3f). Furthermore we recently proposed a new heralded scheme to overcome this limitation 42 where we propose two methods(in addition to the time gated method used here) which utilize the difference in lifetime between the biexciton and exciton states and/or the cascaded nature of the emission to separate the resulting two photon emission in time. Critically we have shown that the use of these methods lead to better efficiencies depending on the original biexciton and exciton quantum efficiencies.…”

Modelling Markovian light-matter interactions for quantum optical devices in the solid state

“…The methods and results presented in sections 3.2 and 3.3 provide a detailed picture of the time dynamics and quantum properties of imperfect photonic states. This can be used to optimize post-processing methods such as temporal filtering [254] to minimize the effect of pure dephasing and unwanted multi-photon noise on the desired state. The content of section 3.3 also provides a basis to study the effect of emitter imperfections on more complicated processes, such as photonic graph state generation for all-optical quantum repeaters [255].…”

Fabrication of Efficient Single‐Emitter Plasmonic Patch Antennas by Deterministic In Situ Optical Lithography using Spatially Modulated Light

“…The distinct rapidity of multiexciton emission allows for temporal filtering via post processing as shown in Figure 3d, e. The possibility of temporal filtering can be exploited to make such antennas better single photon sources [34]. As long as the exciton quantum yield of the QD is stable, the ant-enna emission can be switched very rapidly between single photon and multiphoton emission by varying the excitation intensity-this effect can find application in optoelectronic technologies [35].…”