Titanium-based transition-edge photon number resolving detector with 98% detection efficiency with index-matched small-gap fiber coupling.
We have realized a high-detection-efficiency photon number resolving detector at an operating wavelength of about 850 nm. The detector consists of a titanium superconducting transition edge sensor in an optical cavity, which is directly coupled to an optical fiber using an approximately 300-nm gap. The gap reduces the sensitive area and heat capacity of the device, leading to high photon number resolution of 0.42 eV without sacrificing detection efficiency or signal response speed. Wavelength dependent efficiency in fiber-coupled devices, which is due to optical interference between the fiber and the device, is also decreased to less than 1% in this configuration. The overall system detection efficiency is 98%±1% at wavelengths of around 850 nm, which is the highest value ever reported in this wavelength range.
National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan. d.fukuda@aist.go.jp
Daiji
D
Fukuda
Go
G
Fujii
Takayuki
T
Numata
Kuniaki
K
Amemiya
Akio
A
Yoshizawa
Hidemi
H
Tsuchida
Hidetoshi
H
Fujino
Hiroyuki
H
Ishii
Taro
T
Itatani
Shuichiro
S
Inoue
Tatsuya
T
Zama
D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D010783:Photometry / Q000295:instrumentation*; D017785:Photons; D012031:Refractometry / Q000295:instrumentation*; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects; D014159:Transducers
D014025:Titanium