Fig. 4: Discrete frequency MIR images of water.
From: High-speed scanless entire bandwidth mid-infrared chemical imaging

Water was filled into three microchannels with a wide of 200 µm and deep of 25 µm. In the middle microchannel, water starts to evaporate from the upper and the water flows due to surface tension. The water in the left and right microchannels has not yet started to evaporate, thus the MIR has been absorbed all the time and shows a dark distribution. The MIR is no longer absorbed by the water at the position after the water has flowed away, thus showing a brighter distribution. The time resolution is 0.2 ms and the exposure time is 1 µs per frame. a 6 frames shown here are images extracted every 350 frames, that is, every 70 ms. The size of the images is 1200 µm × 900 µm (640 × 480 pixels). The bit depth of the high-speed imaging of discrete wavelengths is 8 bit. b Temporal evolution of the intensity at the two marked 30 × 30 pixels. The recorded video is given in Supplementary Movie 2.