• Photonics Research
  • Vol. 13, Issue 7, 1810 (2025)
Najia Sharmin1, Huajun Tang1, Chandra Jinata1,2, Ningbo Chen1..., Bingfeng Li3, Nikki Pui Yue Lee3, Yitian Tong1,4,* and Kenneth K. Y. Wong1,2,5,*|Show fewer author(s)
Author Affiliations
  • 1Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China
  • 2Advanced Biomedical Instrumentation Center, Hong Kong SAR, China
  • 3Department of Surgery, The University of Hong Kong, Hong Kong SAR, China
  • 4e-mail: tongyt89@hku.hk
  • 5e-mail: kywong@eee.hku.hk
  • show less
    DOI: 10.1364/PRJ.553103 Cite this Article Set citation alerts
    Najia Sharmin, Huajun Tang, Chandra Jinata, Ningbo Chen, Bingfeng Li, Nikki Pui Yue Lee, Yitian Tong, Kenneth K. Y. Wong, "1725-nm HOPE for segmentation-enabled quantitative photoacoustic microscopy of intrahepatic lipids," Photonics Res. 13, 1810 (2025) Copy Citation Text show less

    Abstract

    Photoacoustic microscopy (PAM) operating within the 1.7-μm absorption window holds great promise for the quantitative imaging of lipids in various biological tissues. Despite its potential, the effectiveness of lipid-based PAM has been limited by the performance of existing nanosecond laser sources at this wavelength. In this work, we introduce a 1725-nm hybrid optical parametric oscillator emitter (HOPE) characterized by a narrow bandwidth of 1.4 nm, an optical signal-to-noise ratio (OSNR) of approximately 34 dB, and a high spectral energy density of up to 480 nJ/nm. This advanced laser source significantly enhances the sensitivity of photoacoustic imaging, allowing for the detailed visualization of intrahepatic lipid distributions with an impressive maximal contrast ratio of 23.6:1. Additionally, through segmentation-based analysis of PAM images, we were able to determine steatosis levels that align with clinical assessments, thereby demonstrating the potential of our system for high-contrast, label-free lipid quantification. Our findings suggest that the proposed 1725-nm HOPE source could be a powerful tool for biomedical research and clinical diagnostics, offering a substantial improvement over current technologies in the accurate and non-invasive assessment of lipid accumulation in tissues.
    Contrast ratio=ImaxImin,

    View in Article

    RMS contrast=(1Ni=0N1(IiImean)2)12,

    View in Article

    Percentage steatosis by area=NlipidNliver×100%,

    View in Article

    Najia Sharmin, Huajun Tang, Chandra Jinata, Ningbo Chen, Bingfeng Li, Nikki Pui Yue Lee, Yitian Tong, Kenneth K. Y. Wong, "1725-nm HOPE for segmentation-enabled quantitative photoacoustic microscopy of intrahepatic lipids," Photonics Res. 13, 1810 (2025)
    Download Citation