Polarization-independent photon up-conversion with a single lithium niobate waveguide

Area of Science:

• Quantum Optics and Photonics
• Materials Science (Lithium Niobate)

Background:

• Single-photon detection is crucial for quantum information processing and communication.
• Existing methods often struggle with polarization dependence and efficiency at telecom wavelengths.
• Periodically poled lithium niobate (PPLN) waveguides offer potential for nonlinear optical processes.

Purpose of the Study:

• To propose a polarization-independent up-conversion protocol for single-photon detection.
• To achieve efficient up-conversion of single photons at the telecom band (1550 nm).
• To utilize a single thin-film periodically poled lithium niobate waveguide.

Main Methods:

• Design of a thin-film periodically poled lithium niobate waveguide.
• Engineering waveguide dispersion to compensate for crystal birefringence.
• Achieving simultaneous quasi-phase-matching for transverse electric (TE) and transverse magnetic (TM) modes.

Main Results:

• Demonstration of a polarization-independent up-conversion scheme.
• Simultaneous fulfillment of quasi-phase-matching conditions for both TE and TM modes using a single poling period.
• Achieved a normalized conversion efficiency of 163.8%/W cm² for randomly polarized single photons at 1550 nm.

Conclusions:

• The proposed protocol enables polarization-independent single-photon up-conversion.
• The engineered PPLN waveguide effectively compensates for birefringence, simplifying the setup.
• This method offers a promising solution for efficient single-photon detection in the telecom band.