Curved detectors for astronomical applications: characterization results on different samples

Area of Science:

• Astronomy and Astrophysics
• Optics and Photonics
• Semiconductor Device Physics

Background:

• Future astronomical surveys face challenges with increasing dimension, complexity, and cost.
• New technologies are required to develop more compact and simpler astronomical systems.
• Curved detectors offer enhanced optical system performance and system compactness.

Purpose of the Study:

• To assess the impact of the curving process on the electro-optical performance of CMOS detectors.
• To characterize curved 20 Mpix CMOS detectors (CMOSIS CMV20000) for astronomical applications.
• To compare the performance of curved detectors against their flat counterparts.

Main Methods:

• Developed and characterized five curved CMOS detectors (20 Mpix) with varying radii of curvature and spherical shapes (convex and concave).
• Performed a full electro-optical characterization, including gain, full well capacity, dynamic range, dark current, readout noise, and pixel-relative non-uniformity.
• Compared measurements from curved detectors to a flat CMOS sensor of the same type as a reference.

Main Results:

• Most electro-optical characterization values showed no significant difference between curved and flat detectors.
• Curved detectors exhibited slightly lower readout noise (10e⁻) and larger dynamic ranges compared to the flat sensor (11e⁻).
• Consistently smaller dark current values were measured for the curved detectors.

Conclusions:

• The curving process does not significantly impact the performance of these CMOS detectors.
• These results are a crucial first step toward the astronomical implementation of curved detectors.
• Curved detectors hold promise for enabling more compact and efficient future astronomical instruments.