Ultrahigh-sensitivity high-linearity photodetection system using a low-gain avalanche photodiode with an ultralow-noise readout circuit.
A highly sensitive photodetection system with a detection limit of 1 photon/s was developed. This system uses a commercially available 200-microm-diameter silicon avalanche photodiode (APD) and an in-house-developed ultralow-noise readout circuit, which are both cooled to 77 K. When the APD operates at a low gain of approximately 10, it has a high-linearity response to the number of incident photons and a low excess noise factor. The APD also has a high quantum efficiency and a dark current of less than 1 e/s at 77 K. This photodetection system will shorten measurement time and permit higher spatial and wavelength resolution for near-field scanning optical microscopes.
Akiba
Makoto
M
Basic and Advanced Research Department, National Institute of Information and Communications Technology, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan. akiba@nict.go.jp
Fujiwara
Mikio
M
Sasaki
Masahide
M