Development of Flat Silicon-Based Mesh Lens Arrays for Millimeter and Sub-millimeter Wave Astronomy

Area of Science:

• Astrophysics
• Optical Engineering
• Materials Science

Background:

• Future cosmic microwave background (CMB) instruments demand highly sensitive focal plane arrays with thousands of detectors.
• Coupling detectors to telescope optics presents significant challenges for current technologies.
• Existing solutions like phased-array antenna-coupled detectors and lenslet-coupled planar antennas face limitations in electromagnetic performance, manufacturing, and scalability.

Purpose of the Study:

• To present a novel approach for fabricating flat metal-mesh lenslet arrays.
• To adapt existing mesh-filter technology for silicon substrates, improving mechanical compatibility with detector arrays.
• To evaluate the performance of these novel lenslets for millimeter-wavelength applications.

Main Methods:

• Utilizing established mesh-filter technology to create flat metal-mesh lenslet arrays.
• Adapting a polypropylene-based mesh lens design to silicon substrates.
• Fabricating and testing prototype pixels operating at millimeter wavelengths.

Main Results:

• Demonstrated a novel method for producing flat metal-mesh lenslet arrays on silicon.
• Achieved good mechanical integration with silicon-based detector arrays.
• Presented measured performance data for prototype pixels at millimeter wavelengths.

Conclusions:

• The novel metal-mesh lenslet arrays offer a promising solution for detector-optic coupling in CMB instruments.
• The silicon-based design addresses mechanical compatibility and manufacturability challenges.
• The technology shows potential for meeting the stringent requirements of next-generation CMB observatories.