Stimulated emission depletion (STED) microscopy is a powerful super-resolution microscopy technique that enables observation of macromolecular complexes and sub-cellular structures with spatial resolution well below the diffraction limit. However, resolution in the double-digit nanometer range can be obtained only using high intensity depletion laser, at the cost of increased photo-damage, which significantly limits STED applications in live specimens. To minimize this, we use the separation by lifetime tuning (SPLIT) technique, in which phasor analysis is used to efficiently distinguish photons emitted from the center and from the periphery of the excitation spot of a STED microscope. Thus, it can be used to improve the resolution without increasing the STED beam intensity. Our approach utilizes a combination of pulsed excitation and pulsed depletion lasers to record the time-resolved photons by FastFLIM. The photons stream are successively analyzed using the SPLIT technique, demonstrating that the resolution improves without increasing the depletion laser intensity.

Date Published: 22 February 2019
PDF: 11 pages
Proc. SPIE 10882, Multiphoton Microscopy in the Biomedical Sciences XIX, 108820I (22 February 2019); doi: 10.1117/12.2513219

Published in SPIE Proceedings Vol. 10882:
Multiphoton Microscopy in the Biomedical Sciences XIX
Ammasi Periasamy; Peter T. C. So; Karsten König, Editor(s)