Optics

Quantum Dots as Single-Photon Sources

Quantum Dots as Single-Photon Sources

Our team has worked on leveraging quantum dots (QDs) as high-performance single-photon sources for advanced quantum technologies, with particular emphasis on indistinguishability, tunability, and telecom-wavelength emission. These systems represent a robust platform for scalable quantum communication, computation, and photonic networking.

Key Contributions:

1. Strain-Tunable Single-Photon Sources
   We developed elastically tunable single QDs embedded in nanowire waveguides. These structures demonstrated high brightness and transform-limited spectral linewidths, essential for scalable quantum networks. The nanowire design facilitated up to 1.2 meV spectral tuning, enabling indistinguishability among QDs for quantum networking.

2. Telecom-Wavelength Quantum Dots
   Quantum dots emitting at telecom wavelengths (O- and C-bands) were demonstrated to produce high-quality, indistinguishable single photons. Through resonance fluorescence, we achieved coherent photon generation with minimal dephasing. These results are critical for long-distance quantum communication and compatibility with existing optical fiber networks.

3. Mitigation of Dephasing Mechanisms
   Our studies addressed intrinsic semiconductor dephasing mechanisms, such as nuclear spin bath fluctuations, using novel resonance fluorescence techniques. Screening nuclear field fluctuations allowed for the generation of indistinguishable photons with high visibility in two-photon interference.

4. Flexible and On-Demand Photon Emission
   We implemented a flexible triggering system for single-photon generation, enabling real-time control over photon emission timing. This approach ensures compatibility with dynamic quantum circuits and scalable quantum communication systems.

Practical Applications:

• Quantum Networks: These single-photon sources are pivotal for quantum key distribution and quantum repeaters.
• Quantum Computing: High indistinguishability and tunability facilitate linear optical quantum computing.
• Photon-Based Sensors: Potential use in metrology and quantum-enhanced imaging.

 

Selected Publications

1. Kremer, P.E., Dada, A.C., et al. Strain-tunable quantum dot embedded in a nanowire antenna. Physical Review B, 90, 201408(R) (2014).
2. Al-Khuzheyri, R., Dada, A.C., et al. Resonance fluorescence from a telecom-wavelength quantum dot. Applied Physics Letters, 109, 163104 (2016).
3. Malein, R.N.E., Dada, A.C., et al. Screening nuclear field fluctuations in quantum dots for indistinguishable photon generation. Physical Review Letters, 116, 257401 (2016).
4. Dada, A.C., et al. Indistinguishable single photons with flexible electronic triggering. Optica, 3(5), 493–499 (2016).
5. Sapienza, L., Dada, A.C., et al. Magneto-optical spectroscopy of single charge-tunable InAs/GaAs quantum dots emitting at telecom wavelengths. Physical Review B, 93, 155301 (2016).