Presentation + Paper
27 August 2022 Broadband spectral characterization of lossy dielectrics for mm/submm optical applications
Fabio Columbro, Andrea Occhiuzzi, Luca Lamagna, Lorenzo Mele, Paolo de Bernardis, Silvia Masi, Francesco Piacentini, Giampaolo Pisano
Author Affiliations +
Abstract
In many astrophysical instruments, optical elements and absorbers are extensively used and can alter the status of input polarized light. In particular in mm-wave experiments the lack of knowledge of material properties is becoming the most critical issue in controlling systematic effects. We developed a pipeline of test and analysis to characterize absorbing materials through the measurement of reflectance and transmittance spectra over a broad range of frequencies (from 200 GHz to 800 GHz) and incident angles (up to 70°). Spectra were acquired with a Martin-Puplett interferometer, coupled with a cryogenic bolometer detector. The setup is characterized by using a Neoprene sample (1 mm thick). The aliasing, the reproducibility and the incidence angle error are analyzed to evaluate the impact on the measurements. Individual one-day sessions ensure the capability to characterize transmittance/reflectance with high signal-to-noise: error < 0.5% in the 300-800 GHz band and ∼ 2% in the 200-300 GHz. A Monte Carlo-based fitting method is used to retrieve the physical properties of the sample. The thickness 1.005±0.016 mm is compatible with the one measured with calipers. The measured refractive index at 200 GHz is n=2.416±0.032.
Conference Presentation
© (2022) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Fabio Columbro, Andrea Occhiuzzi, Luca Lamagna, Lorenzo Mele, Paolo de Bernardis, Silvia Masi, Francesco Piacentini, and Giampaolo Pisano "Broadband spectral characterization of lossy dielectrics for mm/submm optical applications", Proc. SPIE 12180, Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave, 121802H (27 August 2022); https://doi.org/10.1117/12.2628131
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KEYWORDS
Reflectivity

Transmittance

Mirrors

Monte Carlo methods

Fourier transforms

Refractive index

Error analysis

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