Terahertz single-photon detectors based on quantum wells

Abstract

Semiconductor charge-sensitive infrared phototransistors (CSIPs) based on quantum wells are described. They are the only detectors that are able to count single photons in the terahertz region at present. In terms of the noise equivalent power (NEP), the detectors show experimental values of 7 × 10−20 W/Hz1/2, while theoretically expected values are even much lower. These NEP values are by several orders of magnitude lower than any other state-of-the-art highly sensitive detectors. In addition to the outstanding sensitivity, the detectors are featured by strong advantage of huge current responsivity (>1 × 105 A/W) and low output impedance (<10 kΩ). This excellent performance in the above has been obtained for λ = 12–28 μm. By introducing a modified scheme of detection (called “lateral-escape”) along with an improved coupler structure (bowtie antenna), we have achieved similar excellent performance for 45 μm. The CSIP provides extremely promising detectors for a variety of applications covering a wide spectral range of 12–100 μm.

THz Pulse Detection by Multilayered GeTe/Sb2Te3

“…On the one hand, a 2D-arrayed bolometer cameras have already been commercialized; on the other hand, the sensitivity is relatively low. Recent noticeable developments of semiconductor and superconductor quantum wells and quantum dots − as well as nanocarbon-based detectors − have realized very high sensitivity. However, fabrication of such detector devices is problematic from the industrial point of view, and some of them require low temperatures, high magnetic fields, or both.…”

Subcycle measurement of intensity correlations in the terahertz frequency range

“…One possibility to circumvent the absence of materials with bandgaps in the Terahertz is the use of detectors based on intersubband transitions such as Quantum Cascade Detectors or Quantum Well Infrared Photoconductors [17] and on single charge sensing in confined heterostructures [18,19]. However, these detectors have limited use for quantum statistics measurements due to their high dark count rate (QWIP) or a relatively long dwell time.…”

Terahertz single photon detectors

“…"垂直逃逸"结构CSIP的结构如图6(a)所示 [41] , 这 "垂直逃逸"结构在长波长段灵敏度较差. 为了克 服这一问题, 2012年, Wang等人 [58] 提出如图7所示的 "横向逃逸"结构CSIP探测器.…”

“…量子密钥分发 [81] (QKD)技术是量子通信技术 的基础. 在QKD系统中, 传输的量子态信号极其微弱, [22]~1 % [22] 0.001 [22] 30 dB [29] 70-400 mK [29] 双量子点探测器~10 −21 [27]~0 .1% [27] 0.01 [27] 10 5 -10 6 [29] 70-400 mK [29] "垂直逃逸"CSIP 7×10 −20 [41]~7 % [41] ->10 6[33] 4.2 K [33] "横向逃逸"CSIP -~10% [41] ->10 6[58] 4.2 K [58] QCD <10 −20 [50] ≥90% [50] --≤100 mK [44] Nanobolometer 9×10 −21 [70] ---65 mK [70] a) 根据文献推算结果…”