Deterministically fabricated spectrally-tunable quantum dot based single-photon source

Abstract

Spectrally-tunable quantum light sources are key elements for the realization of long-distance quantum communication. A deterministically fabricated single-photon source with a photon extraction efficiency of η =(20 ± 2) %, a maximum tuning range of ΔE = 2.5 meV and a minimum g(2)(τ = 0) = 0.03 ± 0.02 is presented. The device consists of a single pre-selected quantum dot (QD) monolithically integrated into a microlens that is bonded onto a piezoelectric actuator via gold thermocompression bonding. Here, a thin gold layer simultaneously provides strain transfer and acts as a backside mirror for the QD-microlens to maximize the photon extraction efficiency. The QD-microlens structure is patterned via 3D in-situ electron-beam lithography (EBL), which allows us to pre-select and integrate suitable QDs based on their emission intensity and energy with a spectral accuracy of 1 meV for the final device. Together with strain fine-tuning, this enables the scalable realization of single-photon sources with identical emission energy. Moreover, we show that the emission energy of the source can be stabilized to µeV accuracy by closed-loop optical feedback. Thus, the combination of deterministic fabrication, spectral-tunability and high broadband photon-extraction efficiency makes the QD-microlens single-photon source an interesting building block for the realization of quantum communication networks.

Deterministically fabricated quantum dot single-photon source emitting indistinguishable photons in the telecom O-band

“…Therefore, the effect of creep on the wavelength stability is an important issue to address. One can efficiently stabilize the emission wavelength, as it was reported for quantum light emitting diode 6 and later also realized for deterministically fabricated InAs/GaAs QD microlense, 12 wavelength stability are shown in the Table 1. Evaluation of the recorded µPL time trances yield that best spectral stabilization with an standard deviation of the emission wavelength (energy) of 5.6 pm (4.1 µeV) could be achieved for PG = 100 and IT = 0.01 s. Moreover, we found that by increasing PG, the stabilization time decrease.…”

“…9,10 This parameter can possibly be increased in the future by applying the present manufacturing method to sources based on circular Bragg resonators that promise broadband photon extraction efficiency up to η = 95% in the telecom O-band. 11 Noteworthy, and in contrast to previous work on piezoelectric tuning of QD-micromesas emitting in the 930 nm range, 12 To demonstrate strain-tuning and to quantify the corresponding spectral shift, the QD emission is studied in dependence of the applied voltage to the piezoelectric actuator. The applied voltage was varied from -400 V to +400 V, which corresponds to an electric field F of -13.4 kVcm -1 to +13.4 kVcm -1 , and results in a spectral tuning range of 0.5 nm for the present sample, as shown in Fig.…”

“…This behavior is similar to earlier observations in piezo-controlled QD devices. 6,12,13 In addition, we examined the relative change of the emission energies of X, XX and CX and we found that the binding energy is only slightly influenced, on a scale of 0.3 meV, by the applied strain (see SI Fig. S3).…”

Thermal effects on the resonance fluorescence of doubly dressed artificial atoms

“…Recent progress in growth and manipulation of nanometric heterostructures has indeed demonstrated the analogy between atoms and solid-state zero-dimensional systems to impressive levels, so that despite emerging in the quantum optics realm decades after natural atoms, QD-based emitters for many purposes not only match but potentially may also surpass their atomic counterpart [3,4].…”

Исследование оптических и структурных свойств трехмерных островков InGaP(As), сформированных методом замещения элементов пятой группы

“…В настоящее время большой интерес проявляется к созданию приборов для управления одиночными фотонами [1][2][3][4][5][6][7][8][9] и нейроморфных вычислений, использующих в качестве излучателей полупроводниковые гетероструктуры с пониженной размерностью [10][11][12]. Наилучшими кандидатами на роль активных областей для излучателей в таких системах являются квантовые точки (КТ).…”