Search

Your search keyword '"Zhang, Weijun"' showing total 24 results
Start Over Author "Zhang, Weijun" Journal optics express
24 results on '"Zhang, Weijun"'

8. Polarization resolving and imaging with a single-photon sensitive superconducting nanowire array

Author

Jia Huang, Zhang Weijun, Xing-Qu Sun, Lixing You, Xiaoming Xie, Chengjun Zhang, Zhen Wang, Hao Li, Guang-Zhao Xu, and Hui Zhou

Subjects
Physics, Photon, Extinction ratio, Physics::Instrumentation and Detectors, Linear polarization, business.industry, Detector, Nanowire, Polarimeter, 02 engineering and technology, 021001 nanoscience & nanotechnology, Polarization (waves), 01 natural sciences, Atomic and Molecular Physics, and Optics, 010309 optics, Optics, Temporal resolution, 0103 physical sciences, 0210 nano-technology, business
Abstract

Superconducting nanowire single-photon detectors (SNSPDs) have attracted remarkable interest for visible and near-infrared single-photon detection due to their outstanding performance. However, conventional SNSPDs are generally used as binary photon-counting detectors. Another important characteristic of light, i.e., polarization, which can provide additional information of the object, has not been resolved using the standalone SNSPD. In this work, we present a first prototype of the polarimeter based on a four-pixel superconducting nanowire array, capable of resolving the polarization state of linearly-polarized light at the single-photon level. The detector array design is based on a division of focal plane configuration in which the orientation of each nanowire division (pixel) is offset by 45°. Each single nanowire pixel operates as a combination of a photon detector and almost linear polarization filter, with an average polarization extinction ratio of ∼10. The total system detection efficiency of the array is ∼1% at a total dark count rate of 680 cps, with a timing jitter of 126 ps, when the detector array is free-space coupled and illuminated with 1550-nm photons. The mean errors of the measured angle of polarization and degree of linear polarization were about -3° and 0.12, respectively. Furthermore, we successfully demonstrated polarization imaging at low-light level using the proposed detector. Our results pave the way for the development of a single-photon sensitive, fast, and large-scale integrated polarization polarimeter or imager. Such detector may find promising application in photon-starved polarization resolving and imaging with high spatial and temporal resolution.

Published
2021

9. Waveguide-coupled superconducting nanowire single-photon detectors based on femtosecond laser direct writing

Author

Lixing You, Xiao-Yun Xu, Zhang Weijun, Hou Xintong, Xian-Min Jin, Guang-Zhao Xu, Hao Li, Xuan-Lun Huang, Zhen Wang, and Ruo-Jing Ren

Subjects
Materials science, business.industry, Detector, Nanowire, Physics::Optics, 02 engineering and technology, Quantum channel, 021001 nanoscience & nanotechnology, 01 natural sciences, Atomic and Molecular Physics, and Optics, law.invention, 010309 optics, Optics, law, 0103 physical sciences, Femtosecond, Photonics, Quantum information, 0210 nano-technology, business, Waveguide, Electronic circuit
Abstract

The implementation of quantum information technologies requires the development of integrated quantum chips. Femtosecond laser direct writing (FLDW) waveguides and superconducting nanowire single-photon detectors (SNSPDs) have been widely applied in integrated quantum photonic circuits. In this work, a novel FLDW waveguide-coupled SNSPD was designed and realized by integrating FLDW waveguides and conventional SNSPDs together. Through a COMSOL simulation, a waveguide end face-nanowire optical coupling structure was designed and verified. The simulation results showed that the FLDW waveguide-coupled SNSPD device, which had a target wavelength of 780 nm, can achieve 87% optical absorption. Then the preparation process of the FLDW waveguide-coupled SNSPD device was developed, and the fabricated device achieved a system detection efficiency of 1.7% at 10 Hz dark count rate. Overall, this method provides a feasible single-photon detector solution for future on-chip integrated quantum photonic experiments and applications.

Published
2021

23. Unmanned-aerial-vehicle-borne cavity enhanced albedometer: a powerful tool for simultaneous in-situ measurement of aerosol light scattering and absorption vertical profiles.

Author

Zhou J, Zhao W, Fang B, Xu X, Wang S, Liu Q, Zhang W, and Chen W

Abstract

Vertical profiles of aerosol light scattering (b scat ), absorption (b abs ), as well as the single scattering albedo (SSA, ω), play an important role in the effects of aerosols on climate, air quality, and local photochemistry. High-precision in-situ measurements of the vertical profiles of these properties are challenging and therefore uncommon. We report here the development of a portable cavity-enhanced albedometer operating at λ = 532 nm for use aboard an unmanned aerial vehicle (UAV). Multi-optical parameters, b scat , b abs , extinction coefficient b ext , and ω, can be measured simultaneously in the same sample volume. The achieved detection precisions in laboratory were 0.38, 0.21, and 0.43 Mm -1 for b ext , b scat , and b abs , respectively, for a 1 s data acquisition time. The albedometer was installed on an hexacopter UAV and simultaneous in-situ measurements of the vertical distributions of b ext , b scat , b abs , and ω were realized for the first time. Here we report a representative vertical profile up to a maximum height of 702 m with a vertical resolution of better than 2 m. The UAV platform and the albedometer demonstrate good performance and will be a valuable and powerful tool for atmospheric boundary layer research.

Published
2023
Full Text
View/download PDF

24. Portable cavity ring-down spectrometer for an HO 2 radical measurement: instrument's performance and potential improvement using a narrow linewidth laser.

Author

Wang C, Zhao W, Fang B, Yang N, Cheng F, Hu X, Chen Y, Zhang W, Fittschen C, and Chen W

Abstract

We report the development of a portable cavity ring-down spectrometer (CRDS) for direct and absolute measurement of HO 2 radical concentration using a distributed feedback (DFB) diode laser operating at 1506 nm. The spectrometer has a compact design with all optics in a 1000 × 400 × 140 mm 3 box. At a pressure of 100 mbar and a ring-down time (τ 0 ) of 136 µs, the detection limit of the CRDS spectrometer was ∼ 7.3 × 10 7 molecule/cm 3 (1σ, 10s). The corresponding detection sensitivity was 1.5 × 10 -11 cm -1 , which was close to the state-of-the-art performance. By replacing the DFB diode laser with a narrow linewidth erbium-doped fiber (EDF) laser, the amplitude fluctuation caused by the laser phase noise was reduced and the cavity mode injection efficiency was improved. The sensitivity was improved to 3.9 × 10 -12 cm -1 with a short data-acquisition time of 0.2 s. Compared with the DFB laser, the improvement was nearly an order of magnitude. The use of the narrow linewidth laser is attractive. The instrument can achieve very high sensitivity without the need for a complex locking technique, ensuring simple and ease of use in future field applications.

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results