[Paper Review] Electrically-Pumped Wavelength-Tunable GaAs Quantum Dots Interfaced with Rubidium Atoms

Huiying Huang, Rinaldo Trotta+10 more|arXiv (Cornell University)|Feb 5, 2016

Quantum optics and atomic interactions34 references3 citations

TL;DR

This paper demonstrates the first electrically-pumped, wavelength-tunable GaAs quantum dot LED that emits photons resonant with the D2 transition of 87Rb atoms. By integrating the quantum dot LED with a piezoelectric actuator and coupling it to a 75-mm-long Rb vapor cell, the system achieves a temporal delay of up to 3.4 ns, enabling slow-light effects and advancing hybrid quantum systems for quantum networks.

ABSTRACT

We demonstrate the first wavelength-tunable electrically-pumped source of non-classical light that can emit photons with wavelength in resonance with the D2 transitions of 87Rb atoms. The device is fabricated by integrating a novel GaAs single-quantum-dot light-emitting-diode (LED) onto a piezoelectric actuator. By feeding the emitted photons into a 75-mm-long cell containing warm 87Rb atom vapor, we observe slow-light with a temporal delay of up to 3.4 ns. In view of the possibility of using 87Rb atomic vapors as quantum memories, this work makes an important step towards the realization of hybrid-quantum systems for future quantum networks.

Motivation & Objective

• To develop a tunable, electrically-pumped source of non-classical light compatible with atomic quantum systems.
• To enable resonant coupling between semiconductor quantum dots and Rb atom vapors for quantum interface applications.
• To demonstrate slow-light effects via photon-atom interaction in a hybrid system.
• To advance the integration of solid-state quantum emitters with atomic quantum memories for scalable quantum networks.

Proposed method

• A GaAs single-quantum-dot light-emitting diode (LED) is fabricated with a tunable emission wavelength via strain engineering.
• The LED is monolithically integrated onto a piezoelectric actuator to enable dynamic wavelength tuning through mechanical strain.
• Electroluminescence from the quantum dot is coupled into a 75-mm-long cell containing warm 87Rb atomic vapor.
• The system is operated in a configuration where emitted photons are resonant with the 87Rb D2 transition (790 nm), enabling strong light-matter interaction.
• Photon delay is measured via cross-correlation techniques to observe slow-light effects.
• The device operates under electrical injection, enabling practical, on-chip operation of a tunable quantum light source.

Experimental results

Research questions

• RQ1 Can an electrically-pumped GaAs quantum dot LED be tuned to emit photons resonant with the 87Rb D2 transition?
• RQ2 Can such a source enable observable slow-light effects when coupled to Rb atomic vapor?
• RQ3 Is it feasible to achieve dynamic wavelength tuning in a solid-state quantum emitter for resonant coupling with atomic systems?
• RQ4 Can this hybrid system serve as a building block for scalable quantum networks with integrated quantum memories?

Key findings

• The GaAs quantum dot LED was successfully tuned electrically to emit photons at 790 nm, matching the 87Rb D2 transition.
• A temporal delay of up to 3.4 ns was observed when photons propagated through the Rb vapor cell, demonstrating slow-light effects.
• The system achieved resonant coupling between the electrically driven quantum dot and the atomic vapor, enabling strong light-matter interaction.
• The integration of the LED with a piezoelectric actuator enabled dynamic wavelength tuning, crucial for practical quantum interface applications.
• The device operates under electrical injection, marking a key step toward on-chip, scalable quantum photonic systems.