two-dimensional spectroscopy

two-dimensional spectroscopy
Name	Two-dimensional spectroscopy
Caption	Schematic representation of a 2D electronic spectroscopy pulse sequence
Field	Spectroscopy, Ultrafast science, Chemical physics
Invented	1990s
Developers	Shaul Mukamel, Graham R. Fleming, Mukamel, Steven E. Bradforth, Martin Cho
Institutions	University of California, Berkeley, University of Chicago, Massachusetts Institute of Technology, Stanford University

two-dimensional spectroscopy

Two-dimensional spectroscopy is an ultrafast spectroscopic family of techniques that correlates excitation and detection frequencies to reveal couplings, dynamics, and coherence in molecular, condensed-matter, and materials systems. It extends conventional one-dimensional spectroscopy by resolving interactions along two frequency axes, enabling disentangling of overlapping resonances, tracking energy flow, and mapping quantum coherence. Practitioners developed 2D methods within broader communities at institutions such as University of California, Berkeley, Massachusetts Institute of Technology, Stanford University, and University of Chicago, with influential contributions from figures like Shaul Mukamel and Graham R. Fleming.

Introduction

Two-dimensional spectroscopy originated as an extension of multidimensional techniques inspired by Nuclear Magnetic Resonance, adapted to optical and infrared domains to probe ultrafast dynamics in systems investigated at Bell Labs, IBM Research, and major academic centers. Early theoretical foundations were framed by theorists associated with Tel Aviv University and The Hebrew University of Jerusalem while experimental realizations advanced in laboratories at University of California, Berkeley and California Institute of Technology.

Principles and Techniques

Two-dimensional spectroscopy relies on sequences of coherent optical pulses—often derived from mode-locked lasers developed by groups at Bell Labs and Stanford University—to generate third-order nonlinear signals described by response functions articulated in theoretical work by Shaul Mukamel and colleagues. Variants include 2D electronic spectroscopy (2DES), 2D infrared spectroscopy (2D-IR), and two-dimensional Raman techniques, each linking excitation and detection axes analogous to methods used in Nuclear Magnetic Resonance but probing electronic or vibrational transitions as studied at Max Planck Institute for the Science of Light and ETH Zurich. Pulse shaping and phase-stabilization approaches trace to technologies from Menlo Systems and research groups at MIT and University of Oxford, while heterodyne detection schemes parallel innovations from National Institute of Standards and Technology laboratories.

Experimental Implementations

Implementations of two-dimensional spectroscopy employ ultrafast laser sources—femtosecond oscillators and amplifiers developed by manufacturers and labs such as Coherent (company) and Spectra-Physics—along with pulse-shaping devices originally engineered at École Polytechnique Fédérale de Lausanne and phase-stabilization strategies pioneered at Caltech. Typical setups use boxcar, pump–probe, or pulse-shaper geometries refined at Lawrence Berkeley National Laboratory and Argonne National Laboratory, and detection can involve spectrometers and CCDs from firms like Andor Technology. Cryogenic sample environments from facilities such as Brookhaven National Laboratory and microfluidic sample cells advanced at Harvard University enable studies spanning photosynthetic complexes investigated at California Institute of Technology to semiconductor nanostructures examined at IBM Research.

Applications

Two-dimensional spectroscopy has been applied across interdisciplinary problems: electronic energy transfer in photosynthetic complexes studied by groups at California Institute of Technology, University of Cambridge, and Max Planck Institute for Chemical Energy Conversion; vibrational dynamics in proteins and peptides investigated at University of Chicago and Princeton University; charge-carrier dynamics in perovskite solar cells researched at Massachusetts Institute of Technology and Stanford University; and coherence phenomena in quantum wells and quantum dots explored at Bell Labs and IBM Research. It informs design efforts at industrial and governmental labs including National Renewable Energy Laboratory and Sandia National Laboratories and complements structural methods such as those at Argonne National Laboratory and European Synchrotron Radiation Facility.

Data Analysis and Interpretation

Interpreting 2D spectra employs theoretical and computational frameworks developed by theorists affiliated with Tel Aviv University, University of California, Berkeley, and Harvard University including trajectory-based simulations, response-function formalisms, and cumulant expansions. Analysis pipelines often integrate software tools influenced by algorithms from Lawrence Livermore National Laboratory and machine-learning approaches coming from groups at Google and Microsoft Research to deconvolve spectral congestion, extract lineshapes, and identify cross peaks corresponding to couplings and energy-transfer pathways. Spectral simulations link to models used in quantum-chemistry packages and condensed-matter codes developed at Argonne National Laboratory and Oak Ridge National Laboratory.

Historical Development and Key Contributors

Key conceptual advances trace to early proponents of optical multidimensional spectroscopy including Shaul Mukamel and experimental pioneers like Graham R. Fleming and teams at University of California, Berkeley and Stanford University. Foundational experiments in the 1990s and 2000s involved collaborations among researchers at Caltech, MIT, Bell Labs, and IBM Research. Subsequent methodological refinements and applications were driven by investigators at Max Planck Institute for the Science of Light, ETH Zurich, University of Cambridge, Princeton University, and national labs such as Lawrence Berkeley National Laboratory and Brookhaven National Laboratory.

Category:Spectroscopy