Tag Archives: FUW

Super resolution optical microscope built by Polish student

It’s been a while since I’ve had a microscopy story here and this Jan. 2, 2012 news item on Nanowerk gives me an opportunity to revisit the subject,

Optical microscopes are still second to none when it comes to analyzing biological samples. However, their low resolution, improved only in recent years in STED (Stimulated Emission Depletion) microscopes, continues to be a problem. …

Due to diffraction limit, optical microscopes will never be able to discern details smaller than 200 nanometres –[or so] it was believed only a dozen or so years ago. In recent years, scientists have managed to overcome this limit and build super-resolution devices, including, for example, STED confocal microscopes. A prototype device of this type has recently been built at the Faculty of Physics, University of Warsaw (FUW), as part of Joanna Oracz’s MA thesis. As of next year, the new microscope will be used not only for research in the field of optics but also to analyze biological samples.

I’ve been quite fascinated by the fact that the microscopes used in nanoscale research are haptic (touch) rather than optical. From the news item,

There are many imaging techniques with a resolution of the order of nanometres (billionths of a metre) known to science, for example, electron or atomic force microscopy [emphasis mine – this microscopy is haptic]. These techniques require special preparation of samples and make it possible to observe only the surface itself. When it comes to samples of biological origin, not infrequently living ones, optical microscopy is still second to none. One of its advantages is the possibility of observing the spatial structure of the sample. A major disadvantage, however, is a low resolution.

An optical microscope makes it possible to discern details no smaller than half the wavelength of the light illuminating the sample. This limit is due to diffraction, which makes it impossible to focus the beam of light onto a point. As a result, if we use a red light source with a wavelength of 635 nanometres, we can, at best, see details around 300 nanometres in size.

Here are some details about the new microscope,

The prototype microscope at FUW has a resolution of about 100 nm, over two times higher than that of a standard confocal microscope. [Work is] still underway to increase the resolution. “The advantage of our microscope is the possibility of controlling all parameters and studying the physics of the optical phenomena occurring,” stresses Oracz, currently a PhD student at the Ultrafast Phenomena Lab of the Institute of Experimental Physics FUW. The aim is to reach a resolution of about 60 nm. It would make it possible to observe details as minute as dendritic spines of neurons.

There’s more detail about the microscope at Nanwerk.