Photochromic Rhodamines Provide Nanoscopy with Optical Sectioning

Exciting developments: Switching individual photochromic and fluorescent rhodamine amides enables 3D far‐field optical microscopy with nanoscale resolution, excellent signal-to-noise ratio, and fast acquisition times. The rhodamine amides can be switched on using two photons, which enables 3D detailed imaging of thick and densely stained samples (such as 5-μm silica beads (see image) and living cells) to be constructed.