Ultrafast Quantum Optical Spectroscopies

The NOoQM lab is hosting a sub-group developing quantum optical spectroscopies led by Filippo Glerean, Raymond Davis Jr. Fellow.

Research

Our group explores nonlinear light–matter interactions from a statistical quantum-optical perspective. In analogy to how nonlinear optics examines high-order responses beyond the linear field regime, we investigate the effects emerging in higher-order statistical moments of the quantum electromagnetic field, extending the notion of nonlinearity beyond conventional mean-value observables. This approach establishes a novel spectroscopic framework for probing the quantum nature of light–matter interactions in complex materials by observing phenomena such as single photon emission, squeezing, quantum correlations, and entanglement that arise from intrinsically quantum states of matter. Our research focuses in particular on accessing the ultrafast quantum dynamics of matter, to discover and optically control nonequilibrium states in quantum materials.

Technique: Ultrafast quantum-optical tomography. We study the light-driven quantum optical response with ultrafast resolution by combining pump-probe experiments with quantum state tomography. In detail, our approach [Light. Sci. Appl. 14, 115 (2025)] utilizes an homodyne detection scheme with phase-randomized ultrashort laser pulses, overcoming the limitations of phase-stable interferometers and enabling a robust and efficient reconstruction of the full statistical distribution of the photon number of weak probes containing multiple photons per pulse.

Theme: Spectroscopy of quantum fluctuations in light-driven materials. Understanding the role of low-energy magnetic and electronic quantum fluctuations is crucial for engineering a plethora of quantum phenomena in solid-state systems. Entangled fluctuations rule quantum critical transitions, prevent magnetic order in quantum spin liquids and quantum paraelectricity and act as precursors for non-equilibrium phases, like light-induced superconductivity and ferroelectricity. We aim to reveal the dynamics of quantum fluctuations in complex materials by analyzing how the probe statistics are modified by the interaction with the sample excitations and determine methods to manipulate them on-demand with intense optical pulses.

Theme: Ultrafast control of quantum light sources. Light sources with nonclassical statistical photon distributions, in particular Fock-state emitters that produce a fixed number of photons, are building blocks of quantum technology. We explore complex materials as optically controllable platforms to generate quantum light. We focus in particular in characterizing and manipulating 2-D single-photon emitters at ultrafast timescales. We aim to employ optical pulses to tune the structural and electronic properties of the materials hosting defects and excitons, thereby stimulating the emission of photons with novel attributes.