Frequency-domain STED microscopy for selective background noise suppression

Nanoscopy describes the ability to see beyond the generally accepted optical limit of 200-300 nm. Stimulated emission depletion (STED) microscopy, developed by Stefan W. Hell and Jan Wichmann in 1994, and experimentally demonstrated by Hell and Thomas Klar in 1999, is a super-resolution technique for nanoscopy. STED microscopy has made considerable progress and is widely used in practical research. But its practical use involves some undesirable background noise, which negatively affects spatial...