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Matteo Venturi

Publications and source records attributed to Matteo Venturi.

3 recordsLinked to original sources

Chirally-sensitive optical rectification by isotropic chiral media

Chiroptical sensing is central to gain fundamental insight into electronic, vibrational and rotational degrees of freedom of chiral molecules, and is a cornerstone for nanomedicine and drug discovery platforms. Current chiral sensing technologies to assess the enantiomeric imbalance of chiral pharmaceutical compounds are sensitive to ml volumes but are time-consuming and cannot be integrated on a chip, thus creating a major bottleneck for drug discovery and nanomedicine. Here, we propose a novel chiroptical sensing approach based on optical rectification in a photonic micro-cavity filled by a drug solution with nl volume. We theoretically demonstrate that, upon optical excitation by intense pulsed laser light, such a nonlinear effect produces a chirally-sensitive nV voltage burst at the electrically-gated micro-cavity boundaries, with sign depending solely on the drug enantiomeric imbalance. Our results shed light on the potential of optical rectification as a robust platform for innovative lab-on-a-chip devices enabling chiral sensing with nl sensitivity.

physics.optics

Enhanced vibrational optical activity by near-zero index chiral effective media

The enhancement of the inherently weak optical activity of solvated molecules by superchiral fields, crucial for detecting their chirality, is a research frontier of photonics and the basis of novel chiroptical detection schemes. Here, we show that an effective medium consisting of randomly dispersed metal-based nanoparticles embedded within an optically active solvated drug (aqueous reparixin) can enhance vibrational optical rotation and circular dichroism thanks to superchirality produced by slow light in near-zero index conditions. We evaluate from first principles the effective bianisotropic response of the bulk chiral effective medium, showing that, by adjusting the nanoparticles filling fraction, vibrational optical activity is greatly enhanced by a factor $\simeq 10^2-10^3$ at the near-zero index resonance. Our results are relevant for the development of innovative devices capable of detecting the chirality of low-volume samples, with applications in quantum chemistry and nanomedicine.

physics.optics

Plasmon-enhanced circular dichroism spectroscopy of chiral drug solutions

We investigate the potential of surface plasmon polaritons at noble metal interfaces for surface-enhanced chiroptical sensing of dilute chiral drug solutions. The high quality factor of surface plasmon resonances in both Otto and Kretschmann configurations enables the enhancement of circular dichroism differenatial absorption thanks to the large near-field intensity of such plasmonic excitations. Furthermore, the subwavelength confinement of surface plasmon polaritons is key to attain chiroptical sensitivity to small amounts of drug volumes placed around $\simeq 100$ nm by the metal surface. Our calculations focus on reparixin, a pharmaceutical molecule currently used in clinical studies for patients with community-acquired pneumonia, including COVID-19 and acute respiratory distress syndrome. Considering realistic dilute solutions of reparixin dissolved in water with concentration $\leq 5$ mg$/$ml, we find a circular-dichroism differential absorption enhancement factor of the order $\simeq 20$ and chirality-induced polarization distortion upon surface plasmon polariton excitation.

physics.optics