Wednesday, October 15, 2014


Dr. Stefan Hell and Leica Microsystems are pioneers in the discovery of smallness,
things less than two hundredths of a hair's breadth. A normal light microscope can no longer make these visible, it is a physical limit.  That it is possible to exceed these limits and show processes at the nanoscale in high resolution was shown by physicist Stefan Hell.  For this achievement he is receiving the Nobel Prize.  These achievements also contains quite a bit of Leica and Wetzlar.

Stefan W Hell.jpg
Stefan Walter Hell

For 141 years the law of microscopy by pioneer Ernst Abbe (1840-1905) is in effect. It defines that the resolution limit of a microscope depends on the wavelength of light: Anything smaller than 200 nanometers can no longer be optically visualized in a recognizable resolution, it is totally out of focus.

Nobel Prize winner Stefan Hell has found a way to circumvent the law. He employed fluorescence: A laser pulse can illuminate "colored" molecules under a microscope, a second annular laser pulse cuts off the fluorescence in the outer region of the first light spot, so that the inner light spot is smaller than 200 nanometers.  The process is called STED (Stimulated Emission Depletion) microscopy.  It enables monitoring of processes in the nanometer range in living cells. With the Leica STED microscope resolutions of up to 50 nm are possible.

Wetzlar is the German city of optics.  Already in the mid-19th century a lot of pioneering work had been done here, and today is no different.  The Nobel Prize in Chemistry awarded to Stefan Hell is in honor of the technology developed by him, which makes it possible to do basic biological research at the nanoscale.  The STED microscopes were developed by Leica Microsystems in Wetzlar.  "We were the pioneers in the commercial super-resolution microscopy," says Dr. Tanjef Szellas, Head of light microscopy.

When it was announced that Hell is receiving the Nobel Prize for his discovery, the employees of Leica Microsystems and the professor in Göttingen were elated. Many know him personally.  Employees of Leica Microsystems and Hells research group worked together for a long time, some even switched over to Leica Microsystems.

Hell’s discovery isn’t totally new. Already in the 90s he filed for a patent for the STED microscopy.  Leica Microsystems acquired the exclusive license for the use of the STED-patent in the 90s and worked with Hell on implementing the technology.

Already in 2004 Leica Microsystems introduced the first super-resolution microscope, a predecessor technology of the STED method.  Two years later they received the Innovationspreis (Innovation Award) of the German industry.  2007 followed the first STED microscope. The term "microscope" no longer corresponds to what many know from their biology classes.  Rather, it is a complex high-tech system, as Szellas explained. A STED system could fill a small room, there are laser units, and the microscope is remotely controlled via software and requires a vibration-damped table.  Instead of the eyepiece, the scientists look at monitors; the microscope is connected to a computer.  Scientists can thus see, for example, exactly how a virus enters a cell in the body; the basis for the study of the emergence and treatment of diseases.


150 STED systems have been sold and delivered by Leica Microsystems since 2007, each costing an average 600,000 euros. These high-tech microscopes are used, for example, at the Freie Universität Berlin (Free University Berlin) and the University in Göttingen, where research is done to discover which processes occur in nerve cells.  The findings help to understand how learning and memory functions in the brain.


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  1. What does this have to do with photography?

  2. Well, the Leica STED microscope could be considered to be a special lens which makes it possible to photograph extremely small items, like living cells.
    Since Leica is the first part in the name of this blog, and since Leica Microsystems are part of the four companies carrying the Leica name, I thought this might be an interesting contribution to this blog. Leica Microsystems also owns the rights to the Leica name. Leica Camera AG is using via a licensing agreement.