Abstract
Optical spectroscopy is a powerful tool to investigate the microscopic mechanisms underlying different physical, chemical and biological processes. Ultrafast spectroscopy has played a pivotal role in unveiling the early snapshots of photophysical events with femtosecond time resolution. In its standard implementations, the system under study is subjected to a series of pulses, whose frequencies and time delays are the control knobs. Such setups follow a semiclassical description of light–matter interaction, in which light pulses are treated as electromagnetic waves neglecting their quantum nature. Many current research actions, including the Italian PNRR, are focussing on the possible exploitation of properties of single quantum objects, like state superposition and entanglement, to achieve the so called “quantum advantage”, like the capability to perform computations with quantum-bits which cannot be done with classical computers. Recently, a growing body of theoretical studies has proposed to use quantum states of light, such as squeezed states or entangled photon pairs (EPPs), to enhance also ultrafast optical spectroscopy. Quantum light offers several advantages for spectroscopy, such as enhancing signal-to-noise ratio, providing novel control knobs (such as energy, time and polarization entanglement of the EPPs) for designing experiments or even generating completely new signals with respect to classical light. Despite the plethora of theoretical proposals, experimental demonstrations of nonlinear spectroscopy with quantum light are very limited. CRESCENDO aims to replace the classical probes in ultrafast spectroscopy with EPPs and experimentally demonstrate the "quantum advantage" in terms of sensitivity and novel spectroscopic signals for the study of molecular systems and aggregates. As a model system we choose dimers and oligomers of Zinc-Phthalocyanine, an important category of porphyrin dyes with unique optical magnetic and electronic properties. CRESCENDO is a multidisciplinary effort combining an experimental group with world-class expertise in nonlinear optics and ultrafast spectroscopy with two world-leading theoretical groups in the fields of computational photochemistry and non-adiabatic quantum dynamics. The project has the following scientific objectives: - to generate an efficient source of EPPs using nonlinear frequency conversion, and experimentally characterize their joint spectral properties in view of their spectroscopic applications. - to develop the theoretical tools required to model ultrafast spectroscopy with quantum light for realistic molecular systems. - to use EPPs in order to probe exciton-exciton interactions in molecular dimers/oligomers, both in the presence and in the absence of a background excitonic population. - to compare experimental results with numerical simulations and finally provide the first demonstration of the quantum advantage in ultrafast spectroscopy with quantum light.
Dettagli del progetto
Responsabile scientifico: Marco Garavelli
Strutture Unibo coinvolte:
Dipartimento di Chimica Industriale "Toso Montanari"
Coordinatore:
Politecnico di MILANO(Italy)
Contributo totale Unibo: Euro (EUR) 64.072,00
Durata del progetto in mesi: 24
Data di inizio
28/09/2023
Data di fine:
28/02/2026
