Controlling the efficiency of an artificial light-harvesting complex.
Adaptive femtosecond pulse shaping in an evolutionary learning loop is applied to a bioinspired dyad molecule that closely mimics the early-time photophysics of the light-harvesting complex 2 (LH2) photosynthetic antenna complex. Control over the branching ratio between the two competing pathways for energy flow, internal conversion (IC) and energy transfer (ET), is realized. We show that by pulse shaping it is possible to increase independently the relative yield of both channels, ET and IC. The optimization results are analyzed by using Fourier analysis, which gives direct insight to the mechanism featuring quantum interference of a low-frequency mode. The results from the closed-loop experiments are repeatable and robust and demonstrate the power of coherent control experiments as a spectroscopic tool (i.e., quantum-control spectroscopy) capable of revealing functionally relevant molecular properties that are hidden from conventional techniques.
Stichting voor Fundamenteel Onderzoek der Materie (FOM) Institute for Atomic and Molecular Physics, 1098 SJ, Amsterdam, The Netherlands. savolainen@amolf.nl
Janne
J
Savolainen
Riccardo
R
Fanciulli
Niels
N
Dijkhuizen
Ana L
AL
Moore
Jürgen
J
Hauer
Tiago
T
Buckup
Marcus
M
Motzkus
Jennifer L
JL
Herek
D004735:Energy Transfer; D005583:Fourier Analysis; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry*; D010788:Photosynthesis; D013057:Spectrum Analysis / Q000379:methods*
D045342:Light-Harvesting Protein Complexes