The Max Planck Society has awarded Ioachim Pupeza and his team a technology transfer grant, aiming at validating interferometry-based differential molecular fingerprinting of biofluids. The team has pioneered the femtosecond-laser-based technologies underlying high-sensitivity infrared field-resolved spectroscopy (IR-FRS) for liquid-phase molecular fingerprinting [1]. Thereby, molecular vibrations in the sample are resonantly excited by few-cycle, waveform-stable IR pulses. The electric field coherently re-emitted in the wake of the excitation carries most of the sample-specific spectroscopic information.
The new project aims at the demonstration of the potential of spectroscopically detecting minute differences in the composition of two different samples by means of interferometry, cf. schematic above: Two copies of the same excitation are propagated along the arms of an interferometer, each containing a reference and a test probe. Broadband destructive interference [2] spatially separates the electric field making up the difference between the molecular composition of the two liquids. This difference can then be detected free of technical noise carried by the excitation or the vibrations of the molecules equally contained in the two probes. The project builds a bridge connecting basic research on electric-field-resolved spectroscopy and broadband interferometers to analytical application. In particular, the successful implementation will benefit biomedical applications pursued at attoworld by the BIRD (Broadband Infrared Diagnostics) research group.
[1] I. Pupeza, M. Huber, M. Trubetskov, W. Schweinberger, S.A. Hussain, C. Hofer, K. Fritsch, M. Poetzlberger, L. Vamos, E. Fill, T. Amotchkina, K.V. Kepesidis, A. Apolonski, N. Karpowicz, V. Pervak, O. Pronin, F. Fleischmann, A. Azzeer, M. Zigman, F. Krausz, “Field-resolved infrared spectroscopy of biological systems,” Nature 577, 52-59 (2020)
[2] T. Buberl, P. Sulzer, A. Leitenstorfer, F. Krausz, I. Pupeza, “Broadband interferometric subtraction of optical fields,” Optics Express 27, 2432 (2019)