Measurement and modeling of microlenses fabricated on single-photon avalanche diode arrays for fill factor recovery

Single-photon avalanche diode (SPAD) imagers typically have a relatively low fil factor, i.e. a low proportion of the pixel's surface is light sensitive, due to in-pixel circuitry. We present a microlens array fabricated on a 128x128 single-photon avalanche diode (SPAD) imager to enhance its sensitivity. The benefit and limitations of these light concentrators are studied for low light imaging applications. We present a new simulation software that can be used to simulate microlenses' performance under different conditions and a new non-destructive contact-less method to estimate the height of the microlenses. Results of experiments and simulations are in good agreement, indicating that a gain >10 can be achieved for this particular sensor. (C) 2014 Optical Society of America


Published in:
Optics Express, 22, 4, 4202-4213
Year:
2014
Publisher:
Washington, Optical Soc Amer
ISSN:
1094-4087
Laboratories:




 Record created 2014-04-14, last modified 2018-03-17


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