A Power-Efficient Coplanar Waveguide Design for Enhanced Optical Readout in h-BN Quantum Sensors

Area of Science:

• Quantum Sensing
• Materials Science
• Nanotechnology

Background:

• Growing interest in spin-active boron vacancy (VB-) defects in hexagonal boron nitride (hBN) for quantum sensing.
• Current hBN quantum sensors face limitations in optical readout and signal noise due to inefficient waveguide designs.
• Existing waveguides hinder microwave absorption, leading to reduced optically detected magnetic resonance (ODMR) contrast.

Purpose of the Study:

• To advance hBN-integrated quantum sensors by developing an improved waveguide design.
• To overcome limitations of conventional two-port waveguides in hBN quantum sensing devices.
• To enhance optical readout efficiency and signal-to-noise ratio for magnetic field detection.

Main Methods:

• Development of a compact, single-port coplanar waveguide (CPW) for hBN quantum sensors over three generations.
• Integration of on-chip optical and microwave excitation capabilities within the CPW design.
• Characterization of the sensor's performance, including ODMR contrast and radio frequency (RF) magnetic field concentration.

Main Results:

• Achieved a high ODMR contrast of approximately 28% at low microwave power (400 mW).
• Demonstrated improved impedance stability and high RF magnetic field concentration without affecting spin properties.
• Enhanced sensor efficiency by three times and reduced RF power usage by five times.

Conclusions:

• The developed single-port CPW is a significant advancement for hBN-integrated quantum sensors.
• The miniaturized sensor design offers robust performance at lower microwave power, ideal for scalable applications.
• This technology enables more efficient and sensitive magnetic field detection using quantum sensing.