• Advanced Photonics Nexus
  • Vol. 2, Issue 2, 026011 (2023)
Guyue Hu1, Qiao Ran2, Beth Wing Lam So3, Mingsheng Li1, Jiawei Shi1, Xin Dong1, Jiqiang Kang1、4、*, and Kenneth K. Y. Wong1、4、*
Author Affiliations
  • 1The University of Hong Kong, Faculty of Engineering, Department of Electrical and Electronic Engineering, Hong Kong, China
  • 2The University of Hong Kong, School of Biological Sciences, Hong Kong, China
  • 3The University of Hong Kong, School of Biomedical Sciences, LKS Faculty of Medicine, Pokfulam, Hong Kong, China
  • 4Hong Kong Science Park, Advanced Biomedical Instrumentation Centre, Hong Kong, China
  • show less
    DOI: 10.1117/1.APN.2.2.026011 Cite this Article Set citation alerts
    Guyue Hu, Qiao Ran, Beth Wing Lam So, Mingsheng Li, Jiawei Shi, Xin Dong, Jiqiang Kang, Kenneth K. Y. Wong. Noncontact photoacoustic lipid imaging by remote sensing on first overtone of the C-H bond[J]. Advanced Photonics Nexus, 2023, 2(2): 026011 Copy Citation Text show less

    Abstract

    Lipid imaging by conventional photoacoustic microscopy subjects to direct contact sensing with relatively low detection bandwidth and sensitivity, which induces superficial imaging depth and low signal-to-noise ratio (SNR) in practical imaging scenarios. Herein, we present a photoacoustic remote sensing microscopy for lipid distribution mapping in bio-tissue, featuring noncontact implementation, broad detection bandwidth, deep penetration depth, and high SNR. A tailored high-energy pulsed laser source with a spectrum centered at 1750 nm is used as the excitation beam, while a cofocused 1550 nm continuous-wave beam is used as the probe signal. The pump wavelength is selected to overlap the first overtone of the C-H bond in response to the intensive absorption of lipid molecules, which introduces a much-enhanced SNR (55 dB) onto photoacoustic remote sensing (PARS) signals. Meanwhile, the optical sensing scheme of the photoacoustic signals provides broadband detection compared to the acoustic transducer and refrains the bio-samples from direct contact operations by eliminating the ultrasonic coupling medium. Taking merits of the high detection sensitivity, deep penetration depth, broadband detection, and high resolution of the PARS system, high-quality tissue scale lipid imaging is demonstrated in a model organism and brain slice.
    δn(x,t)=ηn0(x)3p(x,t)2ρv2,

    View in Article

    ΔR=|n1+δnn2n1+δn+n2|2R,

    View in Article

    ΔR1=|n1+δn(x,t)1n2n1+δn(x,t)1+n2|2R,

    View in Article

    ΔR2=|n1+δn(x,t)2n2n1+δn(x,t)2+n2|2R.

    View in Article

    ΔR12=ΔR1ΔR2|δn(x,t)1δn(x,t)2|2=k2,

    View in Article

    Guyue Hu, Qiao Ran, Beth Wing Lam So, Mingsheng Li, Jiawei Shi, Xin Dong, Jiqiang Kang, Kenneth K. Y. Wong. Noncontact photoacoustic lipid imaging by remote sensing on first overtone of the C-H bond[J]. Advanced Photonics Nexus, 2023, 2(2): 026011
    Download Citation