Bond-selective transient phase imaging via sensing of the infrared photothermal effect

Delong Zhang; Lu Lan; Yeran Bai; Hassaan Majeed; Mikhail E Kandel; Gabriel Popescu; Ji-Xin Cheng

doi:10.1038/s41377-019-0224-0

Bond-selective transient phase imaging via sensing of the infrared photothermal effect

Light Sci Appl. 2019 Dec 11:8:116. doi: 10.1038/s41377-019-0224-0. eCollection 2019.

Authors

Delong Zhang^#^{1

2}, Lu Lan^#¹, Yeran Bai^{1

3

4}, Hassaan Majeed⁵, Mikhail E Kandel⁶, Gabriel Popescu^{5

6}, Ji-Xin Cheng^{1

7

8}

Affiliations

¹ 1Department of Biomedical Engineering, Boston University, Boston, MA 02215 USA.
² 2Department of Physics, Zhejiang University, Hangzhou, 310028 China.
³ National Laboratory on High Power Laser and Physics, Shanghai, 201800 China.
⁴ 4Key Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800 China.
⁵ 5Department of Bioengineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801 USA.
⁶ 6Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801 USA.
⁷ 7Department of Electrical & Computer Engineering, Boston University, Boston, MA 02215 USA.
⁸ 8Photonics Center, Boston University, Boston, MA 02215 USA.

^# Contributed equally.

Abstract

Phase-contrast microscopy converts the phase shift of light passing through a transparent specimen, e.g., a biological cell, into brightness variations in an image. This ability to observe structures without destructive fixation or staining has been widely utilized for applications in materials and life sciences. Despite these advantages, phase-contrast microscopy lacks the ability to reveal molecular information. To address this gap, we developed a bond-selective transient phase (BSTP) imaging technique that excites molecular vibrations by infrared light, resulting in a transient change in phase shift that can be detected by a diffraction phase microscope. By developing a time-gated pump-probe camera system, we demonstrate BSTP imaging of live cells at a 50 Hz frame rate with high spectral fidelity, sub-microsecond temporal resolution, and sub-micron spatial resolution. Our approach paves a new way for spectroscopic imaging investigation in biology and materials science.

Keywords: Infrared spectroscopy; Phase-contrast microscopy.

Abstract

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