Single-shot linear dichroism optical-resolution photoacoustic microscopy

Yingying Zhou; Jiangbo Chen; Chao Liu; Chengbo Liu; Puxiang Lai; Lidai Wang

doi:10.1016/j.pacs.2019.100148

Single-shot linear dichroism optical-resolution photoacoustic microscopy

Photoacoustics. 2019 Nov 19:16:100148. doi: 10.1016/j.pacs.2019.100148. eCollection 2019 Dec.

Authors

Yingying Zhou^{1

2

3}, Jiangbo Chen^{2

4}, Chao Liu^{2

4}, Chengbo Liu⁵, Puxiang Lai^{1

3}, Lidai Wang^{2

4}

Affiliations

¹ Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong.
² Department of Biomedical Engineering, City University of Hong Kong, Hong Kong.
³ The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.
⁴ City University of Hong Kong Shenzhen Research Institute, Shenzhen, China.
⁵ Research Laboratory for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.

Abstract

Dichroism is a material property that causes anisotropic light-matter interactions for different optical polarizations. Dichroism relates to molecular types and material morphology and thus can be used to distinguish different dichroic tissues. In this paper, we present single-shot dichroism photoacoustic microscopy that can image tissue structure, linear dichroism, and polarization angle with a single raster scanning. We develop a fiber-based laser system to split one laser pulse into three with different polarization angles, sub-microseconds time delay, and identical pulse energy. A dual-fiber optical-resolution photoacoustic microscopy system is developed to acquire three A-lines per scanning step. In such a way, dichroism imaging can achieve the same speed as single-wavelength photoacoustic microscopy. Moreover, the three polarized pulses originate from one laser pulse, which decreases pulse energy fluctuations and reduces dichroism measurement noise by ∼35 %. The new dichroism photoacoustic imaging technique can be used to image endogenous or exogenous polarization-dependent absorption contrasts, such as dichroic tumor or molecule-labeled tissue.

Keywords: Linear dichroism; Photoacoustic microscopy; Polarization.