Quasi-phase-matched concurrent nonlinearities in periodically poled KTiOPO(4) for quantum computing over the optical...

Area of Science:

• Nonlinear optics
• Quantum computing
• Crystal engineering

Background:

• Second-harmonic generation (SHG) is crucial for frequency conversion in optics.
• Periodically poled crystals offer enhanced nonlinear optical effects.
• Scalable quantum computing requires efficient light sources and frequency conversion methods.

Purpose of the Study:

• To experimentally implement three types of coincident nonlinear interactions for second-harmonic generation.
• To demonstrate a multigrating, periodically poled potassium titanyl phosphate (KTiOPO4) crystal as a key component for quantum computing.
• To achieve efficient 780 nm light generation from a 1560 nm pump beam.

Main Methods:

• Design and fabrication of a single multigrating, periodically poled KTiOPO4 crystal.
• Experimental setup for coincident nonlinear interactions: ZZZ (type 0), ZYY (type I), and YYZ/YZY (type II).
• Utilizing a 1560 nm pump beam to generate 780 nm light via second-harmonic generation.

Main Results:

• Successful experimental implementation of ZZZ, ZYY, and YYZ/YZY second-harmonic generation.
• Demonstration of efficient 780 nm light generation from a 1560 nm pump beam.
• Validation of the multigrating crystal as a viable nonlinear medium.

Conclusions:

• The developed multigrating KTiOPO4 crystal enables efficient, coincident nonlinear interactions for second-harmonic generation.
• This nonlinear medium is a critical component for building scalable quantum computers.
• The technology facilitates quantum information processing using optical frequency combs from optical parametric oscillators.