Advancements in Filtering Technology for Large Aperture Cryogenic Detector Arrays 8 views

Next-generation cosmic microwave background (CMB) experiments, such as the Simons Observatory and the proposed CMB-S4 experiment, require large-format far-infrared metal mesh filters with aperture diameters of 500–600 mm to manage the thermal loading on cryogenic detector arrays operating at 0.1 K. The standard fabrication technique of UV photolithography presents a significant production ob- struction at these scales, motivating the development of Direct Write Laser Ablation (DWA) as a mask-free, cost-effective alternative. This thesis investigates the use of a consumer-grade xTool S1 2W 1064 nm infrared laser to fabricate complementary inductive (high-pass) and capacitive (low-pass) metal mesh filters on aluminized My- lar substrates of 0.002 inch (50.8 μm) and 0.005 inch (127 μm) thickness, targeting a 170–260 GHz band-pass filter for CMB observations. Inductive (high-pass) filters were successfully fabricated on both substrate thicknesses, while capacitive (low-pass) grid fabrication was not achieved. Three technical pathways to resolving this problem were identified as including design pre-processing, relaxed grid geometry, and higher- resolution laser platforms. These results demonstrate that consumer-grade DWA on aluminized Mylar is a viable fabrication route for inductive metal mesh filters, with clear potential for scale-up to the production requirements of large-aperture cryogenic CMB surveys.

MS (Master of Science)

English

2026-05-02