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#depletion laser

2 public questions tagged with this topic.

Microscopy

Which microscopy achieves lateral resolution of ~20-70 nm using a depletion laser?

STED achieves 20-70 nm lateral resolution through targeted depletion. Excitation spot is narrowed by overlaying doughnut-shaped STED laser that quenches peripheral fluorophores via stimulated emission, leaving emission from nanometer-scale center. Resolution scales inversely with STED beam intensity, breaking diffraction barrier without requiring stochastic blinking or molecular reconstruction. Originally developed by Stefan Hell, it uses organic dyes compatible with high-intensity depletion. STORM relies on photo-switching rather than depletion, while SIM uses Moiré and TEM uses electrons. ST

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

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Microscopy

Which super-resolution microscopy technique uses a depletion laser to confine excitation to a nanometer scale region?

STED microscopy breaks diffraction by superimposing two synchronized lasers. A diffraction-limited excitation beam is overlapped by a doughnut-shaped depletion beam that drives stimulated emission at periphery, quenching fluorescence everywhere except central zero-intensity spot. This confined emissive region shrinks to 20-70 nm laterally, enabling super-resolution imaging of living cells. Unlike stochastic localization methods requiring extensive computational reconstruction, STED achieves resolution through targeted deterministic de-excitation, providing rapid scanning without heavy post-pro

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

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