Fakultät für Physik und Astronomie

Physikalisches Kolloquium am 23.01.2023: Challenges Towards High Efficiency Low Noise Quantum Dot Single Photon Sources

20.01.23 | Physikalisches Kolloquium, Veranstaltung

Am Montag (23.01.2023) um 12.00 Uhr c.t. findet der nächste Termin unseres Physikalischen Kolloquiums statt.

Referent ist Dr. Arne Ludwig (RUB) zum Thema: „Challenges Towards High Efficiency Low Noise Quantum Dot Single Photon Sources“.

A key component for photonic quantum devices is a source of high-fidelity photonic qubits, a single photon source (SPS) [1]. A promising route to create such a device employs semiconductor quantum dots (QDs) in photonic cavities. These QDs behave like artificial atoms displaying fully quantized electronic states. Moreover, the exquisite toolbox of semiconductors, in particular scalable manufacturing is at hand. However, noise processes hampering solid state emitters [2]. A main contributor to decoherence and low efficiency is random charge rearrangements in the semiconductor environment or the QD itself. A random change of the QD’s charge state from e.g. Auger processes [3] or photoionization [4] can switch the emitter temporarily off [3,5]. Noise from a fluctuating electrostatic environment is called charge noise. One way to efficiently suppress this, is to embed the QDs in the high purity material undoped region of a p-i-n-diode tunnel-coupled to a charge reservoir [6,7]. Following this approach, a highly efficient fiber-coupled SPS with an end-to-end efficiency of 57% has been developed [8].

We found a method to periodically modulate the density of QDs [9]. This recent progress in understanding epitaxial growth finalizes the presentation.


[1] P. Senellart et al., Nat Nano 12, 1026 (2017).

[2] A.V. Kuhlmann et al., Nat Phys 9, 570 (2013).

[3] A. Kurzmann et al., Nano Lett 16, 3367 (2016).

[4] P. Lochner et al., Phys. Rev. B 103, 075426 (2021).

[5] G. Gillard et al., npj Quantum Inf 7, 43 (2021).

[6] D. Najer et al., Nature 575, 622 (2019).

[7] L. Zhai et al., Nat Commun 11, 4745 (2020).

[8] N. Tomm et al., Nat Nano 16, 399 (2021).

[9] N. Bart et al., Nat Commun 13, 1633 (2022).

Abstract Vortrag Dr. Arne Ludwig

Die Einführung erfolgt durch Prof. Dr. Ilya Eremin.

Die Fakultät lädt alle Interessierten herzlich ein. Die Veranstaltung findet im Hörsaal HNC 10 und hybrid via Zoom statt. Vor dem Kolloquium bieten wir Ihnen Kaffee und Kekse an. Über diesen Link gelangen Sie zur Zoom-Veranstaltung (MeetingID: 632 5520 9938, Passwort: 526977). Alle Termine des Physikalischen Kolloquiums finden Sie hier.

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