Technique - (15) Ultrafast 2D electronic spectroscopy

Type: Experimental

Description: 2D Fourier-transform spectroscopy probing quantum coherences on femtosecond timescales.

Department(s)/lab(s): School of Physics | Curmi Molecular Biophysics Laboratory @ UNSW
Summary:

Curmi is a structural and single-molecule biophysicist whose most-cited work is on the light-harvesting antenna proteins of cryptophyte algae, where he and collaborators reported long-lived electronic coherence at ambient temperature — one of the founding results of the quantum-biology field and still one of its most argued-over. His group determines the structures of these antenna complexes and engineers them, and separately works on protein-based molecular motors and on single-molecule fluorescence and FRET measurements of conformational dynamics. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — Curmi supplies the biological systems in which quantum coherence is actually claimed to matter; a pT/sqrt(Hz)-class spin sensor capable of watching radical-pair or exciton dynamics in situ would be aimed at exactly the questions his structures raise. Preferred attribute present: genuine quantum-biology substrate rather than a quantum-flavoured metaphor.

Department(s)/lab(s): Chemistry / PME | Engel Group @ UChicago
Summary:

Research focuses on quantum dynamics and excited-state reactivity in biological and synthetic light-harvesting systems. Discovered long-lived quantum coherence in photosynthetic light-harvesting complexes (FMO, 2007). Develops 2D electronic spectroscopy techniques to probe excitonic transport, open quantum systems, and photochemical reaction dynamics on femtosecond timescales. Director NSF QuBBE; co-director Berggren Center for Quantum Biology and Medicine.

Department(s)/lab(s): Chemistry | Fayer Group @ Stanford
Summary:

Fayer's group develops and applies ultrafast 2D infrared spectroscopy to resolve structural dynamics of water, proteins, and complex fluids on femtosecond-to-picosecond timescales, pushing the temporal resolution of vibrational spectroscopy well past what linear methods can access.

Department(s)/lab(s): Chemistry | Fleming Ultrafast Spectroscopy Lab @ UCB
Summary:

Fleming pioneered two-dimensional electronic spectroscopy and used it to reveal long-lived quantum coherences in photosynthetic light-harvesting complexes, work that reframed how energy transfer efficiency in natural and artificial light-harvesting systems is understood.

Department(s)/lab(s): Chemistry | Gaynor Group (Ultrafast & Attosecond Spectroscopy) @ Northwestern
Summary:

Prof. Gaynor (Chemistry, joined summer 2023) develops cutting-edge ultrafast spectroscopy at the physics-chemistry frontier. Directions: (1) Attochemistry — new ultrafast laser spectroscopies operating on attosecond to femtosecond timescales to directly measure how electron spin and orbital motion couple to molecular geometry (spin-vibronic coupling) in chiral molecules and materials of interest for energy conversion and spintronics; (2) Multidimensional nonlinear spectroscopy (2D electronic spectroscopy, 2D vibrational) to track energy and charge transfer immediately after photoexcitation; (3) Instrumentation-first approach: building novel attosecond transient absorption and correlation spectroscopy apparatus from scratch, enabling entirely new observables (e.g., electron-nuclear and spin-orbital correlations). INQUIRE faculty affiliate. Beckman Young Investigator 2025 ($600k, 4 yrs); Packard Fellow 2025 ($875k, 5 yrs).

Department(s)/lab(s): Department of Chemistry, Institute of Inorganic and Analytical Chemistry | AK Heinze - Molecular Photophysics @ JGU
Summary:

Heinze designs earth-abundant luminescent metal complexes -- the 'molecular ruby' (Cr(III)) family and its Mo(III) NIR-II-emitting analogues -- and studies their excited-state dynamics with time-resolved luminescence, ultrafast spectroscopy and EPR, in collaboration with spin-spectroscopy groups including van Slageren at Stuttgart. Applications targeted include optical sensing (oxygen, pressure, temperature), NIR-II imaging in the tissue-transparency window, and photocatalysis. Relative to the established NV-ensemble quantum-sensing playbook (DEER, nanoscale NMR, T1 relaxometry at pT/sqrt(Hz) ensemble sensitivity), this is a dye/label-based sensing inclusion rather than a spin-defect one: the emphasis is on engineering the emitter's photophysics so that lifetime and intensity report on the local environment, which is directly comparable to nanodiamond thermometry/relaxometry but at the molecular scale.

Department(s)/lab(s): School of Chemistry | Molecular Photophysics Group (Lakhwani) @ USyd
Summary:

Lakhwani runs the Molecular Photophysics Group and is a chief investigator in ARC Exciton Science. The group works on strong light-matter coupling in organic semiconductors: forming exciton-polaritons in microcavities, driving them toward polariton lasing and condensation with electrically injected devices, and engineering host-guest energy funnelling to lower thresholds. A second thread is chiroptical spectroscopy — circular dichroism and circularly polarised luminescence of chiral organic films — which is a polarisation-resolved measurement of a very small differential signal. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — polaritonic quantum matter is a distinct route to non-classical states of light at room temperature, in contrast to the cryogenic or spin-based platforms that dominate pT/sqrt(Hz)-class sensing; the differential chiroptical measurements the group performs are, methodologically, small-signal detection problems of exactly the same type.

Department(s)/lab(s): Physics (Cavendish Laboratory) | Rao Group - Optoelectronics @ Cambridge
Summary:

Rao's group uses ultrafast (sub-20 fs) transient absorption and vibronic spectroscopy to study quantum-coherent energy and charge transfer processes in molecular and nanoscale semiconductor systems, most notably the quantum-coherent mechanism of singlet exciton fission, with applications to next-generation photovoltaics.

Department(s)/lab(s): Chemistry | Scherer Lab @ UChicago
Summary:

Uses single-molecule spectroscopy, optical trapping, and advanced imaging to study nanoscale systems. Directions: (1) orientation-resolved single-molecule spectroscopy using polarization-controlled excitation and detection; (2) optical trapping of individual nanoparticles and viruses to study force-dependent dynamics; (3) plasmon-enhanced single-molecule detection and imaging beyond diffraction limit; (4) ultrafast spectroscopy of nanoscale energy transfer.

Department(s)/lab(s): Chemistry | Scholes Group @ Princeton
Summary:

Scholes uses multidimensional ultrafast and coherence spectroscopies to probe wavepacket dynamics and quantum-mechanical phenomena in photosynthetic light-harvesting complexes, cavity QED, and photo-activated chemistry, including his group's resolution of a decade-long controversy over long-lived coherent coupling in the Fenna-Matthews-Olson complex. His current work extends coherence spectroscopy to quantum information science and photobiomodulation, squarely fitting the fundamental light-physics/quantum-optics side of the filter.