Browsing by Author "Liu, Bin"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Application of Micro Quartz Tuning Fork in Trace Gas Sensing by Use of Quartz-Enhanced Photoacoustic Spectroscopy
    (MDPI, 2019) Lin, Haoyang; Huang, Zhao; Kan, Ruifeng; Zheng, Huadan; Liu, Yihua; Liu, Bin; Dong, Linpeng; Zhu, Wenguo; Tang, Jieyuan; Yu, Jianhui; Chen, Zhe; Tittel, Frank K.
    A novel quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor based on a micro quartz tuning fork (QTF) is reported. As a photoacoustic transducer, a novel micro QTF was 3.7 times smaller than the usually used standard QTF, resulting in a gas sampling volume of ~0.1 mm3. As a proof of concept, water vapor in the air was detected by using 1.39 μm distributed feedback (DFB) laser. A detailed analysis of the performance of a QEPAS sensor based on the micro QTF was performed by detecting atmosphere H2O. The laser focus position and the laser modulation depth were optimized to improve the QEPAS excitation efficiency. A pair of acoustic micro resonators (AmRs) was assembled with the micro QTF in an on-beam configuration to enhance the photoacoustic signal. The AmRs geometry was optimized to amplify the acoustic resonance. With a 1 s integration time, a normalized noise equivalent absorption coefficient (NNEA) of 1.97 × 10−8 W·cm−1·Hz−1/2 was achieved when detecting H2O at less than 1 atm.
  • Thumbnail Image
    Item
    Sharp-peaked lanthanide nanocrystals for near-infrared photoacoustic multiplexed differential imaging
    (Springer Nature, 2024) Loh, Kang Yong; Li, Lei S.; Fan, Jingyue; Goh, Yi Yiing; Liew, Weng Heng; Davis, Samuel; Zhang, Yide; Li, Kai; Liu, Jie; Liang, Liangliang; Feng, Minjun; Yang, Ming; Zhang, Hang; Ma, Ping’an; Feng, Guangxue; Mu, Zhao; Gao, Weibo; Sum, Tze Chien; Liu, Bin; Lin, Jun; Yao, Kui; Wang, Lihong V.; Liu, Xiaogang
    Photoacoustic tomography offers a powerful tool to visualize biologically relevant molecules and understand processes within living systems at high resolution in deep tissue, facilitated by the conversion of incident photons into low-scattering acoustic waves through non-radiative relaxation. Although current endogenous and exogenous photoacoustic contrast agents effectively enable molecular imaging within deep tissues, their broad absorption spectra in the visible to near-infrared (NIR) range limit photoacoustic multiplexed imaging. Here, we exploit the distinct ultrasharp NIR absorption peaks of lanthanides to engineer a series of NIR photoacoustic nanocrystals. This engineering involves precise host and dopant material composition, yielding nanocrystals with sharply peaked photoacoustic absorption spectra (~3.2 nm width) and a ~10-fold enhancement in NIR optical absorption for efficient deep tissue imaging. By combining photoacoustic tomography with these engineered nanocrystals, we demonstrate photoacoustic multiplexed differential imaging with substantially decreased background signals and enhanced precision and contrast.