Spin memory effect in charged single telecom quantum dots.

Area of Science:

• Quantum Information Science
• Optoelectronics
• Materials Science

Background:

• Quantum dots (QDs) are semiconductor nanocrystals with tunable optical and electronic properties.
• Indium Phosphide (InP)-based QDs emitting in the third telecom window (1530-1565 nm) are crucial for integrating quantum technologies with existing fiber-optic infrastructure.
• Optical spin manipulation in QDs is a fundamental requirement for developing quantum gates and memory devices.

Purpose of the Study:

• To investigate the optical spin writing of carriers in single InP-based quantum dots.
• To explore the potential of these QDs for quantum computing applications compatible with fiber-optic communication.

Main Methods:

• Quasi-resonant optical excitation of single InP-based quantum dots.
• Polarization-resolved microphotoluminescence (PL) spectroscopy.
• Analysis of circular polarization in PL spectra to identify carrier spin dynamics.

Main Results:

• Observation of negative circular polarization in charged quantum dots, confirming optical spin writing of carriers.
• Demonstration of efficient quasi-resonant excitation due to a dense ladder of excited states in the InP QDs.
• Emission at telecom wavelengths, aligning with the requirements for fiber-optic communication.

Conclusions:

• Single InP-based quantum dots exhibit efficient optical spin writing of carriers.
• These QDs are promising candidates for realizing quantum gates and memory devices compatible with fiber-optic networks.
• The findings contribute to the advancement of quantum communication technologies.