Sub-wavelength position measurements with running wave driving fields

Free-running InGaAs/InP Avalanche Photodiode with Active Quenching for Single Photon Counting at Telecom Wavelengths

We present an InGaAs/InP avalanche photodiode with an active quenching circuit on an ASIC (application specific integrated circuit) that is capable of operating in both gated and free-running modes. The 1.6mm2 ASIC chip is fabricated using CMOS (complementary metal oxide semiconductor) technology guaranteeing long-term stability, reliability and compactness. In the free-running mode we find a single photon detection efficiency of 10% with <2kHz of noise.

Liquid-nitrogen cooled, free-running single-photon sensitive detector at telecommunication wavelengths

The measurement of light characteristics at the single- and few photon level plays a key role in many quantum optics applications. Often photodetection is preceded with the transmission of quantum light over long distances in optical fibers with their low loss window near 1550nm. Nonetheless, the detection of the photonic states at telecommunication wavelengths via avalanche photodetectors has long been facing severe restrictions. Only recently, demonstrations of the first free-running detector techniques in the telecommunication band have lifted the demand of synchronizing the signal with the…

An Ultra-Low Noise Telecom Wavelength Free Running Single Photon Detector Using Negative Feedback Avalanche Diode

It is challenging to implement genuine free running single photon detectors for the 1550 nm wavelength range with simultaneously high detection efficiency (DE), low dark noise, and good time resolution. We report a novel read out system for the signals from a negative feedback avalanche diode (NFAD) which allows useful operation of these devices at a temperature of 193 K and results in very low dark counts (~100 CPS), good time jitter (~30 ps), and good DE (~10%). We characterized two NFADs with a time correlation method using photons generated from weak coherent pulses (WCP) and photon pairs …

中红外光驱动的高次谐波相位匹配

Phase-Matching of High-Order Harmonics Driven by Mid- Infrared Light

本文证明使用更长波长的中红外驱动激光可将高次谐波相位匹配截止能量从45 eV提升至100 eV，并缓解高气压下的单原子响应标度问题，为极紫外光源拓展提供新途径。

Detection of ultra-weak laser pulses by free-running single-photon detectors: modeling dead time and dark counts effects

In quantum communication systems, the precise estimation of the detector's response to the incoming light is necessary to avoid security breaches. The typical working regime uses a free-running single-photon avalanche diode in combination with attenuated laser pulses at telecom wavelength for encoding information. We demonstrate the validity of an analytical model for this regime which considers the effects of dark counts and dead time on the measured count rate. For the purpose of gaining a better understanding of these effects, the photon detections were separated from the dark counts via a …

用于电信波长的基于和频的光子数分辨探测器

Sum-frequency-based photon-number-resolving detector for telecom wavelengths

针对量子通信中C波段低强度光的探测需求，提出结合低成本光子数分辨探测器与非线性光学的接收器，实现电信波长灵敏度，验证了1.5μm飞秒光源的泊松特性，为复杂量子方案提供探测支持。