Prof. Xiangping Zhu Profile

Prof. Xiangping Zhu

at XIOPM CAS

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Author

Publications (6)

Proceedings Article | 4 April 2023 Paper

Stand-off detection of explosive hazards based on time-gated Raman spectroscopy

Pu Zhang, Xiangping Zhu, Wenzhen Ren, Bo Wang, Junhong Yang

Proceedings Volume 12617, 126174J (2023) https://doi.org/10.1117/12.2666356

KEYWORDS: Raman spectroscopy, Explosives, Explosives detection, Signal detection, Fluorescence, Light scattering

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There are currently lots of research activities concerning explosive hazards detection, and stand-off detection of explosives is in main focus. The reason for this interest is the occurrence of terrorist attacks on the civilian society involving Improvised Explosives Devices (IED). Laser-based spectroscopies are the only currently viable techniques that can be utilized to detect trace amounts of explosives at stand-off distances. In particular, Raman Spectroscopy (RS) has been shown to be effective for stand-off detection and has the ability to both detect and identify explosive materials. Raman spectroscopy is virtually instantaneous, non-destructive in nature and provides high selectivity. The traditional Raman spectrometer utilizes continuous lasers and CCDs to detection the scattering signal, which greatly limits the application of Raman spectroscopy in the stand-off detection of explosive hazards due to the weak signal, strong background fluorescence, ambient light interference, and long analysis time. Time-gated Raman spectroscopies are based on ultrafast pulsed lasers and time-resolved single-photon detection techniques. Through the time-gated method, the Raman signal intensity can be greatly improved, and the influence of fluorescence and environmental light can be effectively suppressed. In this work, the time-gated Raman system utilizing frequency-doubled Nd:YAG lasers at 532 nm excitation was developed. The Cassegrain telescope was coupled to the Raman spectrometer using a fiber optics cable, and notch filter was used to reject Rayleigh scattering light. The Raman scattered light was collected by a telescope and then transferred via fiber optic to spectrometer and finally directed into Intensified CMOS (ICMOS) detector. The applications of time-gated Raman spectroscopy in stand-off detection of hazardous explosives have been performed. The Raman spectra of DNT, TNT, RDX and NaNO₃ at a stand-off distance of 50 m have been identified with a detection limit of 1 mg/cm².

Proceedings Article | 4 April 2023 Paper

Photoelectric characteristics of different micro structures of black silicon etched by femtosecond laser

Xiaomo Zhang, Xiangping Zhu, Yang Liu, Wei Zhao, Chuan Jin, Pu Zhang

Proceedings Volume 12617, 126170S (2023) https://doi.org/10.1117/12.2663330

KEYWORDS: Silicon, Semiconductor lasers, Absorption, Etching, Femtosecond phenomena, Optoelectronic devices, Annealing, Photodetectors, Aluminum, Sensors

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Black silicon, which is characterized as numerous nanospikes induced on bulk silicon, has recently attracted great attention due to its fascinating photoelectric property. Compared with the traditional silicon-based photoelectric sensor, photoelectric sensors based on the black silicon doped with supersaturated chalcogens have shown both excellent photoelectric corresponding efficiency in the visible range and considerable optical absorption efficiency in the near infrared band due to the impurity energy-level introduced by the chalcogens element supersaturated doping. Nonetheless, the differences of surface morphology greatly affect the photoelectric efficiency of black silicon photoelectric sensors, which is quite difficult to control in practice. As one of the mainstream methods in black silicon fabrication, femtosecond laser etching exhibits the ability in manipulate different dimensionality and configurations and provide a clear and flexible research platform. Black silicon can be etched on traditional silicon-based photoelectric sensor with different size of surface morphology according to the size of surface thickness. In this work, by varying the etching energy density of the femtosecond laser, three kinds of black silicon samples with different surface morphology were obtained. At the same time, the surface morphology, size, visible-infrared absorptivity and photoelectric conversion efficiency of black silicon were characterized by scanning electron microscope, spectrophotometer and confocal Raman spectroscopy, etc. We got three sample characterization data, the minimum morphology depth of black silicon can be controlled at 2μm, the maximum visible light absorption efficiency can reach 90%, and the near-infrared absorption efficiency can reach 60% before annealing. Naturally, the photoelectric conversion efficiency has been proven to be significantly improved. Based on the observation of experimental results, it is an important step to understand the photoelectric characteristic of black silicon with different morphologies, which is the application of black silicon in different fields.

Proceedings Article | 27 December 2022 Poster + Paper

A compact killowatt-level QCW high-power semiconductor laser array based on dual-chip integration

Pu Zhang, Wenzhen Ren, Bo Wang, Xiangping Zhu, Junhong Yang

Proceedings Volume 12311, 123110W (2022) https://doi.org/10.1117/12.2643908

KEYWORDS: Semiconductor lasers, High power lasers, Packaging

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Proceedings Article | 24 November 2021 Paper

Standoff detection of explosive materials using time-gated UV-Raman spectroscopy

Bo Wang, Pu Zhang, Shuyao Zhang, Xiangping Zhu, Wei Zhao

Proceedings Volume 12064, 120640Q (2021) https://doi.org/10.1117/12.2606981

KEYWORDS: Raman spectroscopy, Potassium, Standoff detection, Explosives, Explosives detection, Spectroscopy, Raman scattering, Light scattering, Laser energy

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Proceedings Article | 19 February 2015 Paper

Decoding algorithms and spatial resolution Monte Carlo simulation of cross strip anode for UV astronomy

Guobao Deng, Xiangping Zhu

Proceedings Volume 9449, 94490E (2015) https://doi.org/10.1117/12.2075999

KEYWORDS: Microchannel plates, Sensors, Monte Carlo methods, Spatial resolution, Electrodes, Detection and tracking algorithms, Algorithm development, Clouds, Ultraviolet astronomy, Image sensors

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Proceedings Article | 10 February 2009 Paper

A new photon counting imaging detector for the Chinese ChangE-2 EUV explorer mission

Xiangping Zhu, Baosheng Zhao, Yongan Liu, Xinghua Zhang, Zhenhua Miao, Yonglin Wei

Proceedings Volume 7126, 712617 (2009) https://doi.org/10.1117/12.821888

KEYWORDS: Sensors, Microchannel plates, Photomasks, Image sensors, Extreme ultraviolet, Prototyping, Photon counting, Spatial resolution, Mercury, Lamps

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