Title:
OPTICAL DIFFERENCE DETECTOR AND INSPECTION DEVICE
Document Type and Number:
WIPO Patent Application WO/2019/230147
Kind Code:
A1
Abstract:
This optical difference detector 21A is provided with: a first APD 22A and a second APD 22B; a first voltage application unit 23A which applies a first bias voltage to the first APD 22A and a second voltage application unit 23B which applies a second bias voltage to the second APD 22B; a differential amplifier 25 in which the first APD 22A and the second APD 22B are connected in parallel, and which amplifies the difference between a first signal current from the first APD 22A and a second signal current from the second APD 22B; and a feedback control unit 26 which controls the second bias voltage so that a low frequency component of a first monitoring current from the first APD 22A is equal to a low frequency component of a second monitoring current from the second APD 22B.
Inventors:
YAMADA TOSHIKI (JP)
Application Number:
PCT/JP2019/011522
Publication Date:
December 05, 2019
Filing Date:
March 19, 2019
Export Citation:
Assignee:
HAMAMATSU PHOTONICS KK (JP)
International Classes:
H01L31/10; H01L31/107
Domestic Patent References:
| WO2017094495A1 | 2017-06-08 | |||
| WO2014132609A1 | 2014-09-04 |
Foreign References:
| JP2000200922A | 2000-07-18 | |||
| JPS6187440A | 1986-05-02 | |||
| JPH065888A | 1994-01-14 | |||
| US20130334434A1 | 2013-12-19 | |||
| US20110133058A1 | 2011-06-09 | |||
| US7659981B2 | 2010-02-09 |
Other References:
TOMITA, A. ET AL.: "Balanced, gated-mode photon detector for quantum-bit discrimination at 1550 nm", OPTICS LETTERS, vol. 27, no. 20, 2002, pages 1827 - 1829, XP003017634, DOI: 10.1364/OL.27.001827
See also references of EP 3806166A4
See also references of EP 3806166A4
Attorney, Agent or Firm:
HASEGAWA Yoshiki et al. (JP)
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