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team — Molecules are the smallest entities that mediate specific biological functions. They can therefore be regarded as the building blocks of life. Understanding how they behave is therefore of fundamental significance for fields ranging from basic research to medical diagnostics. However, the ability of current technologies such as optical spectroscopy, microscopy and mass spectrometry to quantitatively monitor the motions of molecules during biological processes is quite limited.
In the Laboratory of Attosecond Physics, which is jointly run by the Max Planck Institute for Quantum Optics and LMU Munich, Dr. Ioachim Pupeza’s research group is developing novel and extremely sensitive spectroscopic methods specifically for use in the investigation of complex mixtures of biomolecules. Pupeza and his colleagues exploit the outstanding coherence properties of laser light to repeatedly generate rapid sequences of ultrashort pulses of infrared radiation as probes of molecular dynamics. A typical sequence consists of several million light pulses, with each pulse lasting for a few femtoseconds (1 fs = 10-15 seconds). The pulse trains cause every single molecule in the irradiated sample to vibrate at characteristic resonance frequencies that are determined by, and characteristic of their particular atomic structures.
Since the microscopic oscillations excited in each molecular species are perfectly synchronized, they give rise to measurable variations in the electric field. Together, these constitute a unique ‘optical fingerprint’ that contains information about the chemical composition of each biological sample. Moreover, the unprecedented degree of control over the excitation of the molecules, and the precision with which the resulting electric fields can be measured, maximize the amount of structural information obtainable from the signal. Indeed, this new method of field-resolved spectroscopy reaches the maximum resolution theoretically attainable with optical spectroscopy.
Now Pupeza and his team have been able, for the first time, to measure directly the field oscillations generated by molecules in the liquid phase – the medium in which biomolecules naturally function. Furthermore, these measurements break all existing records for detection sensitivity in the context of molecular infrared vibrational spectroscopy. In his lecture, Pupeza will describe the developments that have led to the new method and provide a preview of the applications opened up by these advances.
Speaker: Dr. Ioachim Pupeza (Max Planck Institute of Quantum Optics)
19 September 2018, at 7 PM (Tickets are available at the box office from 6 PM, Admission fee: 3 Euro)
Venue: Ehrensaal des Deutschen Museums, Museumsinsel 1, München