Time-resolved
optical spectroscopy in which the inhomogeneous broadening of absorbers
is eliminated by the proper choice of geometry in a four-wave mixing experiment.
Notes:
- Term applied to a group of non-linear optical techniques such as integrated echo,
time-gated echo, three-pulse echo peak shift, heterodyne-detected echo and 2D-echo.
- Photon echo techniques make use of the third-order optical polarization and
'hyper-susceptibility'. The main distinguishing feature of photon echo methods
from all other third-order processes is the time ordering of the field interactions
that
leads to a rephasing process in the induced polarization to remove inhomogeneous
contributions to the absorption linewidth.
- In terms of mathematical description, the photon echo is equal to the spin
echo (solid-state physics) from which a term 'echo' was borrowed.
- Technique used, e.g., to probe solvation dynamics upon (ultra-short) pulse
excitation of a chromophore.
Source:
PAC, 2007, 79, 293
(Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006))
on page 394
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
