Polarisation-controlled single photon emission at high temperatures from InGaN quantum dots

Area of Science:

• Quantum Optics
• Materials Science
• Solid-State Physics

Background:

• Solid-state single photon sources are crucial for quantum technology applications.
• Operating these sources above the Peltier cooling limit (200 K) is highly desirable for practical applications.
• Existing sources often require cryogenic temperatures, limiting their widespread use.

Purpose of the Study:

• To realize solid-state single photon sources with polarization control operating above 200 K.
• To investigate the performance of these sources in terms of photon indistinguishability, polarization degree, and repetition rate.
• To assess the temperature stability of these quantum dot-based sources.

Main Methods:

• Utilized a non-polar Indium Gallium Nitride (InGaN) material system.
• Fabricated semiconductor quantum dots using a simple planar epitaxial growth method.
• Characterized single photon emission properties, including second-order coherence (g(2)(0)), polarization degree, and radiative lifetime.

Main Results:

• Achieved single photon emission with g(2)(0) = 0.21, indicating high purity.
• Demonstrated a high polarization degree of 0.80 with a fixed polarization axis.
• Observed GHz repetition rates and a radiative lifetime of 357 ps at an operating temperature of 220 K.
• Showcased temperature-insensitive performance of these properties.

Conclusions:

• Fast, polarization-controlled single photon emission is achievable in solid-state quantum dots above the Peltier temperature threshold.
• The developed InGaN quantum dot system offers a promising platform for on-chip quantum applications.
• The simple fabrication and robust performance make these sources suitable for integrated quantum systems.