A better way to do infrared microspectroscopy

Abstract

A promising microspectroscopy technique has just become even more promising thanks to an improvement that increases the technique’s sensitivity and spatial resolution. The advance, which combines fluorescence microscopy and infrared (IR) spectroscopy, enables scientists to probe chemistry inside living cells and within tiny domains of heterogeneous materials. Barely 5 years old, mid-IR photothermal microscopy provides molecular information from a microscopic region of a specimen by monitoring the temperature changes that result from IR-induced sample heating. The sample absorbs select bands of IR light, which triggers specific molecular vibrations that can be detected as temperature changes and used for chemical fingerprinting and sample mapping. Researchers typically probe the temperature change by monitoring how a beam of visible light scatters from the sample. But scattering depends weakly on temperature, so imaging can be slow and the image quality poor. Working independently, two research teams have come up with a way to sidestep