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229 results on '"Wan, Hongdan"'

3. Label-free, ultra-low detection limit DNA biosensor using high quality optical microcavity functionalized by DNA tetrahedral nanostructure probes

Author

Wan Hongdan, Zhang Shuai, Gu Yu, Xiong Jinxin, Xu Ji, Wan Cheng, and Chao Jie

Subjects
dna tetrahedral nanostructure probes, label-free, limit of detection, single-nucleotide mismatch recognition, surface functionalization, whispering gallery mode, Physics, QC1-999
Abstract

This study proposes and demonstrates a novel label-free DNA biosensor using high quality optical microcavity functionalized by 3D DNA nanostructure probes. To achieve ultra-low limit DNA biosensing, optical sensing interface of the hollow-core, thin wall-thickness microcavity was functionalized by self-assembled DNA tetrahedral nanostructure (DTN) probes with size of 17 bp and length of ∼5.8 nm. High efficiency binding of the DTN probes with the optical sensor interface and the target ssDNA are achieved. Whispering gallery mode (WGM) spectra with high-Q factor of >107 are excited and traced for DNA detection inside the microfluidic channel of the microcavity, with a small sample volume of nL. Incorporation of nanoscale DTN probes onto surface of the optical microcavity makes it an effective way for increasing efficient probe density and eliminating entanglement between DNA probes, thus ∼1000 times lower detection limit is achieved as compared to using 1D ssDNA probes. Due to its desirable merits of label-free, ultra-low LoD, real time and compact size, the proposed DNA biosensor has broad application prospects in bioengineering and medical diagnosis.

Published
2023
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38. Label-Free, Ultralow Detection Limit DNA Biosensor Employing Tilted Fiber Bragg Grating Functionalized by 3-D Nanostructure Probes

Author

Wan, Hongdan, Chen, Yufang, Liang, Zhongwei, Xiong, Jinxing, Wan, Cheng, and Zhang, Zuxing

Abstract

A label-free, ultralow detection limit deoxyribonucleic acid (DNA) biosensor based on tilted fiber Bragg grating (TFBG) is proposed and demonstrated. The optical sensing interface of the TFBG is functioned by self-assembled 3-D tetrahedral DNA nanostructure (TDN) probes with the size of 17 base pairs to greatly enhance the sensing performance for DNA detection. DNA hybridization processes in various concentrations of target DNA solutions are monitored according to the transmission spectral evolution of the TFBG in real-time, interrogated by a narrow-linewidth laser source. Experimental results show that the detection response of the proposed DNA biosensor is ranged from 1 fM to 10 pM, with an ultralow detection limit of ~3.4 aM. Single nucleotide mismatch recognition is also achieved. As compared to the sensing performance using single-strand DNA (ssDNA) probes, the detection limit is about 1000 times lower for using the TDN probes. The proposed DNA biosensor possesses desirable merits as a label-free method, ultralow detection limit, high specificity, and fast response, making it a promising candidate for sensing applications in bioengineering, disease diagnosis, and environmental science.

Published
2023
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39. Tunable, Single-Wavelength Fiber Laser Based on Hybrid Microcavity Functionalized by Atomic Layer Deposition

Author

Wan, Hongdan, Lu, Yao, Liang, Zhongwei, Shen, Zhanyu, Gu, Ping, Hu, Taozheng, and Chen, Jing

Abstract

A tunable fiber laser based on a high-quality-factor (high-Q) hybrid microcavity (HM) is proposed and demonstrated. As far as we know, this is the first report of fabricating the HM by coating TiO2 film with varied thickness on the SiO2 microsphere surface by atomic layer deposition technique, with the Q-factor maintained to be above 107. Ultra-narrow bandwidth whispering gallery mode spectrum of the HM is used for mode-selection in a double-ring fiber cavity, achieving tunable single-wavelength fiber laser output with 3dB bandwidth of about 16.20 pm, signal-to-noise ratio of ∼40 dB and wavelength tuning range of ∼220 pm. The proposed novel tunable, single-wavelength fiber laser with wide tuning range and high compactness can be potentially used for optical communication and sensing applications. © 2022 Optica Publishing Group.

Published
2023
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46. All-Optical Tunable Fiber Filter Based on Phosphate Glass Microspheres

Author

周权 Zhou Quan, 张帅 Zhang Shuai, 沈骁 Shen Xiao, 陈彧芳 Chen Yufang, 毛静怡 Mao Jingyi, and 万洪丹 Wan Hongdan

Subjects
All optical, Materials science, business.industry, Filter (video), Optoelectronics, Fiber, Electrical and Electronic Engineering, business, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Phosphate glass, Microsphere
Published
2021
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49. A 1.0 μm Cylindrical Vector Beam Fiber Ring Laser Based on A Mode Selective Coupler

Author

Wang, Jie, Wan, Hongdan, Cao, Han, Cai, Yu, Sun, Bing, Zhang, Zuxing, and Zhang, Lin

Subjects
Physics::Optics
Abstract

We propose and demonstrate a continuous-wave all-fiber ring laser generating cylindrical vector beams (CVBs) using a MSC as transverse mode converter and mode splitter. The MSC is fabricated by a novel method free of pre-tapering, achieving LP11 mode with a high purity of > 96% near the wavelength of 1064 nm. The CVB fiber laser operates at a center wavelength of 1053.9 nm, with a 3 dB linewidth of less than 0.04 nm and a signal-to-background ratio of > 60 dB. The laser slope efficiency is > 9%. The radially and azimuthally polarized beams can be switched by adjusting the polarization controllers in the fiber ring cavity, with a high mode purity measured to be > 96%.

Published
2018

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