The opening CLEO/Europe-IQEC plenary talk (on May 13, 2013), at the World of Photonics Congress in Munich, discussed far-field optical microscopy and its “particular relevance to life sciences.”
Professor Stefan Hell of the Max Planck Institute for Biophysical Chemistry (Goettingen, Germany), well known for the development of stimulated emission depletion (STED) microscopy, discussed efforts to overcome the diffraction limit (which prevents light from being concentrated at less than 200 nm) that serves as a speed bump to optical imaging at high resolution—and thus has gated scientific discovery.
Hell stated that “nonlinearity is not the best line of thinking” to this end (nonlinear, e.g., multiphoton microscopy, has provided a solution to the problem) and said that a better way to conceptualize the challenge is in terms of on-off switching of various states. He discussed the RESOLFT (REversible Saturable OpticaL Fluorescence Transitions) photo-switching approach, which he said enables imaging at molecular and even atomic scales. An advanced implementation of this approach involves parallelization (that is, the use of arrays) to speed scanning.
This will be an interesting area to watch over time, especially as the first commercial instrument based on RESOLFT, by Abberior Instruments, was on display in the exhibit hall at LASER World of Photonics.