Politecnico di Milano develops device for CARS spectroscopy with single beam and high sensitivity

Researchers at Politecnico di Milano have developed a device for CARS spectroscopy with single beam and high sensitivity. CARS spectroscopy is a powerful tool for fingerprinting of molecules based on their vibrational frequencies. The invention consists of an apparatus for CARS (Coherent Antistokes Raman Scattering) spectroscopy/microscopy with two main characteristics: the use of a single laser source and the high sensitivity, by exploiting interferometric techniques to amplify the CARS signal.

The device allows the simultaneous generation of two/three trains of tunable narrowband (1-20 cm-1) light pulses starting from a single broadband pulse generated by a femtosecond laser. The instrument is based on a technique called “spectral compression”, that allows to convert with high efficiency a broadband femtosecond pulse into a narrowband picosecond pulse, using the nonlinear optical process of second harmonic generation in periodically poled crystals.

This patented technique can be used in two different fields: label-free microscopy for in vivo imaging of biological tissues and live cell and  high sensitivity spectroscopy for the detection of molecules with environmental impact (e.g. carbon and nitrogen compounds) or in biomedicine (NH3, EtOH, NO3 contained, for example, in breath).

The research was conducted by Giulio Cerullo and Marco Marangoni at Politecnico di Milano, and Fabio Baronio, Matteo Conforti and Costantino De Angelis at Università di Brescia.

The patent is available, fur further information contact the Technology Transfer Office at Politecnico di Milano.