Mass-producible and efficient optical antennas with CMOS-fabricated nanometer-scale gap

Area of Science:

• Photonics and Nanotechnology
• Optical Engineering
• Materials Science

Background:

• Optical antennas enable sub-diffraction limit light manipulation for applications like sensing and imaging.
• Current limitations include fabrication challenges and achieving small mode volumes essential for high performance.
• Existing methods struggle with uniform large-area fabrication and efficient designs below 10 nm gap spacing.

Purpose of the Study:

• To introduce a novel arch-dipole optical antenna design.
• To achieve optimal radiation efficiency and a small mode volume (<10 nm gap).
• To demonstrate mass-producible, high-performance optical antennas using CMOS-compatible techniques.

Main Methods:

• Fabrication of arch-dipole antennas using CMOS-compatible deep-UV spacer lithography.
• Characterization of antenna performance, focusing on gap spacing and radiation efficiency.
• Demonstration of surface-enhanced Raman spectroscopy (SERS) using the fabricated antenna arrays.

Main Results:

• The arch-dipole antenna achieved a 5 nm gap spacing, enabling a small mode volume.
• Surface-enhanced Raman spectroscopy (SERS) signal enhancement factor exceeded 10^8.
• The SERS signal was two orders of magnitude stronger than standard dipole antennas fabricated by e-beam lithography.

Conclusions:

• The novel arch-dipole antenna design offers optimal radiation efficiency and small mode volume.
• Deep-UV lithography enables mass production of efficient optical antenna arrays with nanometer-scale gaps.
• This technology advances sensitive photodetection, light emission, and biochemical sensing applications.