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There is a motivation to reduce the thickness of photodetectors to improve the efficiency of extracting executed carrier. However, reducing the thickness of thin film also reduces the amount of light absorbed. To alleviate this problem we can use light trapping. Ag Nanoparticles with specific diameters are exposed to improve optical characteristics of TiO2-based photodetectors. Optical properties...
We present a SWIR detector, which combines resonant structures with injection photodetectors. Room temperature dark current of 8nA at 1V and internal quantum efficiency of 72% were measured. 320-by-256 element arrays were fabricated towards focal plane array integration.
Free space QKD over an atmospheric channel was demonstrated in 1996 for the first time. Since then, several prepare-and-measure and entanglement-based schemes have been implemented (for a detailed overview, see). All of these systems use single-photon detectors, and therefore have to employ spatial, spectral and/or temporal filtering in order to reduce background light. In our system, we use an alternative...
The second-order coherence properties of highly-incoherent cw sources (true blackbody and amplified spontaneous emission) are directly evidenced at femtosecond timescales by use of an interferometric autocorrelator based on a two-photon absorption in a GaAs phototube.
Detection at optical communication wavelength is achieved, for the first time, in GaAs phototube by non degenerate two-photon absorption. Signal photon is supported by a pump field, producing a quantum ldquoleg uprdquo effect.
We employ quantum trajectory theory to model temporally resolved photodetection of collective emission from a pair of atoms to investigate the performance of a conditional quantum teleportation protocol. We include effects of imperfect photodetection.
With photon-number resolving detectors, we show compression of interference fringes with increasing photon numbers for both Michelson and Fabry-Perot interferometers. We also theoretically show supersensitivity for nonclassical light.
The reported experiment observed a nontrivial third-order temporal correlation of chaotic-thermal light in the joint-detection of three individual photodetectors. It seems that the thermal photons are always ldquobunchedrdquo in triples. In the view of quantum mechanics, ldquothree-photon bunchingrdquo is a three-photon interference effect.
In this paper, we design a photonic-based true random number generator (True RNG) which is targeted for cryptographic application .Since all security protocols rely on unpredictability, RNGs for crypto applications must meet stringent requirements. The design employs a single-photon detection to generate a random signal which is useful in producing random output. In contrast with traditionally used...
We present the first quantum tomography of a detector, using as examples an avalanche photodiode and a photon-number resolving detector. The resulting POVM set agrees well with one derived from a model of the detector.
We report a differential phase shift quantum key distribution experiment using up-conversion detectors. Though the detectors had polarization dependency, we were able to make the system polarization-independent by using polarization modulation.
A detection-time-bin-shift scheme for polarization encoding QKD is proposed. This scheme reduces cost and overcomes the security loss caused by dead-time and unbalanced characteristics of detectors. This scheme is experimentally demonstrated with the B92 protocol.
In this study, a "dual detectors" method is proposed to overcome the limitation imposed by the speed-noise trade-off and improve the performance of a practical quantum key distribution (QKD) system based on realistic detectors. The "dual detectors" scheme can be employed to improve the performance of a Gaussian-modulated coherent states (GMCS) QKD system based on realistic homodyne...
We propose a technique to obtain sub-wavelength resolution in imaging with 100% visibility using incoherent light. We can in principle obtain a resolution of lambda/N using coincidence detection of N photons emitted from N excited atoms.
A novel type of quantum key distribution (QKD) protocol called differential-phase-shift QKD is described. It uses a weak coherent pulse train, and features simple configuration and efficient use of the time domain.
The author, Xuechu Shen in Stuttgart and worked with Prof. L.Genzel where we developed double beam and optically Fourier transform spectroscopy, investigated the impurity vibration in crystalline and amorphous semiconductors, as well as vibration spectroscopy of bio-molecules by use of self-developed techniques. In Shanghai the author worked fortunately with many outstanding students where we developed...
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