Ultrafast chemical imaging by widefield photothermal sensing of infrared absorption
Abstract
Infrared (IR) imaging has become a viable tool for visualizing various chemical bonds in a specimen. The performance, however, is limited in terms of spatial resolution and imaging speed. Here, instead of measuring the loss of the IR beam, we utilize a pulsed visible light for a high-throughput, widefield sensing of the transient photothermal effect induced by absorption of single mid-IR pulses. To extract such transient signals, we built a virtual lock-in camera synchronized to the visible probe and IR light pulses with precisely-controlled delays, allowing sub-microsecond temporal resolution determined by the probe pulse width. Our widefield photothermal sensing (WPS) microscope enabled chemical imaging at a speed up to 1250 frames per second, with high spectral fidelity, and offering sub-micron spatial resolution. With the capability of imaging living cells and nanometer-scale polymer films, WPS microscopy opens a new way for high-throughput characterization of biological and material specimens.
- Publication:
-
Science Advances
- Pub Date:
- July 2019
- DOI:
- 10.1126/sciadv.aav7127
- arXiv:
- arXiv:1811.07405
- Bibcode:
- 2019SciA....5.7127B
- Keywords:
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- Physics - Optics;
- Physics - Applied Physics
- E-Print:
- 24 pages, 6 figures