Fresnel-type solid immersion lens for efficient light collection from quantum defects in diamond.

Area of Science:

• Quantum Science and Technology
• Materials Science
• Nanofabrication

Background:

• Quantum defects in diamonds are crucial for quantum information processing.
• Current fabrication methods for enhancing photon collection efficiency are time-consuming and affect accuracy.
• Nitrogen-vacancy (NV-) centers are a leading quantum defect for these applications.

Purpose of the Study:

• To design and fabricate a novel Fresnel-type solid immersion lens (SIL).
• To reduce fabrication time and improve accuracy for quantum defect devices.
• To maintain or enhance photon collection efficiency compared to existing structures.

Main Methods:

• Utilized focused ion beam (FIB) milling to fabricate the Fresnel-type SIL.
• Designed the SIL structure for optimal light coupling to a 5.8 µm-deep NV- center.
• Performed numerical simulations to evaluate performance across various depths.

Main Results:

• Achieved a significant reduction in milling time (1/3 of that for a hemispherical structure).
• Maintained high photon collection efficiency, exceeding 2.24 times that of a flat surface.
• Demonstrated the effectiveness of the Fresnel-type SIL for a 5.8 µm-deep NV- center.

Conclusions:

• The Fresnel-type SIL fabricated by FIB is an efficient method for quantum defect device fabrication.
• This approach offers substantial time savings and high optical performance.
• The benefits are expected to extend to a wide range of milling depths, enhancing quantum technologies.