To realize STED in two dimensions, the diffraction-limited point spread function (PSF) is reduced to a subdiffraction-sized PSF by overlaying a donut-shaped laser beam (“STED beam”) onto the ...

A second laser, called the STED laser, is used to create a donut-shaped intensity profile that overlaps with the excitation laser. The STED laser has a wavelength that matches the emission spectrum of ...

STED microscopy uses small fluorescent particles—fluorophores—in the sample that glow (fluorescence) with the help of an excitation laser. A second laser beam with a donut-shaped cross-section ...