Nonlinear Spectroscopy

Nonlinear Spectroscopy research head is Prof. Aleksander Rebane and current projects are as follows:

1. Femtosecond multiphotonics: From quantitative spectroscopy to quantum optics, PRG611

Project duration: 01.01.20 – 31.12.24

Principal Investigator: Prof. Aleksander Rebane

Nonlinear-optical phenomena, where two or more photons are absorbed or emitted simultaneously, is the basis for emerging multiphoton technology that has revolutionized biological microscopy and has numerous uses from nanofabrication to quantum information. We carry out comprehensive experimental and quantum-chemical modelling study of femtosecond multiphoton absorption (MPA) properties subjected to spontaneous breaking of molecular symmetry and specific solute-solvent interactions in organic compounds including synthetic dyes, organometallic complexes, as well as DNA bases and amino acids, with the goal of quantitative prediction of the efficiency and wavelength dependence of MPA, which will allow, for the first time, rational quantitative design of MPA chromophores for various applications. We will study MPA excitation with quantum-mechanically correlated pairs of photons, for which we will develop a new wavelength-tunable source of biphotons.

Link to ETIS here.


2. Quantitative sensing of intramolecular electric fields by DNA-intercalating organometallic two-photon probes, PSG317

Project duration: 01.03.19 – 31.12.22

Principal Investigator: Dr. Charlie Stark

Deoxyribonucleic acid (DNA) is an essential biomolecule because it carries genetic information coded in the famous double helix built of smaller molecules called nucleotides. But different forms of DNA also encompass far more complex, multi-tier organization that is much less studied because electrostatic forces responsible for tertiary- and quaternary features are notoriously difficult to measure and quantify. Our experiments aim at developing new tool for probing of electric field strength acting inside- and in close vicinity to DNA structures. We will use femtosecond light pulses produced by state-of-the-art ultrafast laser to measure 2-photon absorption spectra of organometallic ruthenium complexes that spontaneously insert themselves (intercalate) between DNA strands. Because 2-photon spectra are exclusively sensitive to electrostatics, we will use these luminescent species as tiny nanometer-scale “molecular voltmeters” to probe forces responsible for important properties of DNA.

Link to ETIS here.

Our high quality work is presented also in Multihoton Spectra database.

Finished projects here.

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