Two-dimensional electronic spectroscopy (2DES) is an ultrafast laser spectroscopy technique that allows studying ultrafast phenomena in condensed-phase systems. The term electronic refers to the fact that the optical frequencies in the visible spectral range are used to excite the electronic energy states of the system.
This technique records the signal emitted from a system after an interaction with a sequence of three laser pulses. Such pulses usually have a time duration of a few hundred femtoseconds, provided by PHAROS or CARBIDE femtosecond lasers. This high time resolution allows capturing of dynamics inside the system that evolves with the same time scale. The main result of this application is a two-dimensional absorption spectrum that shows the correlation between excitation and detection frequencies.
According to Gelžinis et al., the key strengths of 2D spectroscopy are the following. First, the uncoupling of time and excitation frequency resolution allows the researchers to follow specific states’ dynamics with selective excitation and excellent time resolution. Second, the lack of background signals means that an excellent signal-to-noise ratio can be achieved. Third, a single run of 2D spectroscopy provides information with a wide range of excitation frequencies while using the pump-probe technique that requires many separate measurements. All things considered, for the last fifteen years, 2D spectroscopy has contributed heavily to our understanding of excitation dynamics in photosynthetic molecular complexes. It is a safe bet that it will continue to do so for the foreseeable future.
Two-dimensional spectroscopy may be also used in the IR spectral range, where vibrational states are investigated; see two-dimensional infrared spectroscopy (2DIR).
- 100 fs – 20 ps tunable pulse duration
- 4 mJ maximum pulse energy
- 20 W maximum output power
- Single-shot – 1 MHz repetition rate
- Automated harmonic generators (up to 5th harmonic)
- 190 fs – 20 ps tunable pulse duration
- 2 mJ maximum pulse energy
- 80 W maximum output power
- Single-shot – 2 MHz repetition rate
- Air-cooled version
- Combination of best OPA and NOPA features
- 650 – 900 nm and 1200 – 2500 nm tuning range
- Single-shot – 2 MHz repetition rate
- < 100 fs pulse duration
- Adjustable spectral bandwidth
- Long pulse mode for gap-free tunability
- 515 nm, 343 nm, 258 nm, and 206 nm outputs
- Simple selection of active harmonic
- Simultaneous or switchable outputs
- Customizable or high-power and -energy models
Low energy excited state vibrations revealed in conjugated copolymer PCDTBT
S. Irgen‑Gioro, P. Roy, S. Padgaonkar, and E. Harel, The Journal of Chemical Physics 4 (152), 044201 (2020).
Both electronic and vibrational coherences are involved in primary electron transfer in bacterial reaction center
F. Ma, E. Romero, M. R. Jones, V. I. Novoderezhkin, and R. van Grondelle, Nature Communications 1 (10) (2019).
Potential pitfalls of the early-time dynamics in two-dimensional electronic spectroscopy
D. Paleček, P. Edlund, E. Gustavsson, S. Westenhoff, and D. Zigmantas, The Journal of Chemical Physics 2 (151), 024201 (2019).
Exciton–Phonon Spectroscopy of Quantum Dots Below the Single-Particle Homogeneous Line Width
A. P. Spencer, W. O. Hutson, S. Irgen‑Gioro, and E. Harel, The Journal of Physical Chemistry Letters 7 (9), 1503-1508 (2018).
Identification and characterization of diverse coherences in the Fenna–Matthews–Olson complex
E. Thyrhaug, R. Tempelaar, M. J. P. Alcocer, K. Žídek, D. Bína, J. Knoester, T. L. C. Jansen, and D. Zigmantas, Nature Chemistry 7 (10), 780-786 (2018).
Discrimination of Diverse Coherences Allows Identification of Electronic Transitions of a Molecular Nanoring
V. Butkus, J. Alster, E. Bašinskaitė, R. Augulis, P. Neuhaus, L. Valkunas, H. L. Anderson, D. Abramavicius, and D. Zigmantas, The Journal of Physical Chemistry Letters 10 (8), 2344-2349 (2017).
Quantum coherence selective 2D Raman–2D electronic spectroscopy
A. P. Spencer, W. O. Hutson, and E. Harel, Nature Communications 1 (8) (2017).
Dark States in the Light-Harvesting complex 2 Revealed by Two-dimensional Electronic Spectroscopy
M. Ferretti, R. Hendrikx, E. Romero, J. Southall, R. J. Cogdell, V. I. Novoderezhkin, G. D. Scholes, and R. van Grondelle, Scientific Reports 1 (6) (2016).
Mapping multidimensional electronic structure and ultrafast dynamics with single-element detection and compressive sensing
A. P. Spencer, B. Spokoyny, S. Ray, F. Sarvari, and E. Harel, Nature Communications 1 (7) (2016).
Real-time observation of multiexcitonic states in ultrafast singlet fission using coherent 2D electronic spectroscopy
A. A. Bakulin, S. E. Morgan, T. B. Kehoe, M. W. B. Wilson, A. W. Chin, D. Zigmantas, D. Egorova, and A. Rao, Nature Chemistry 1 (8), 16-23 (2015).