Chapter 5
Ligand-Core NLO-Phores
Two-Photon Absorption and Two-Photon
Excited Emission Properties of Atomically
Precise Clusters of Gold and Silver
Rodolphe Antoine
Abstract Functional ligand-protected noble metal cluster nanomaterials with
enhanced two-photon absorption and two-photon excited emission may lead to new
technologies for bio-imaging applications. In this article, I review experimental and
theoretical methodologies allowing detailed investigation of two-photon absorption/
emission properties of ligand-protected silver and gold metal clusters. This includes
femtosecond two-photon excited fluorescence experimental setups and quantum
chemical methodologies based on time-dependent density functional theory.
I thoroughly analyze physical phenomena and trends leading to large two-photon
absorption/emission responses of model nanoclusters focusing on the effects of the
relaxation pathways in the linear and nonlinear optical regime, as well as strategies
aiming at enhancing their two-photon emission responses.
5.1 Introduction
Recent developments in optical imaging techniques, in particular multi-photon
excitation (MPE) microscopy that allows studies of biological interactions at a deep
cellular level, have motivated intensive research in developing multi-photon
absorption fluorophores. Biological tissues are optically transparent in the
near-infrared region. Therefore, fluorophores that can absorb light in the NIR region
by multi-photon absorption are particularly useful in bio-imaging. MPE microscopy
enables molecular imaging by using either exogenous markers or endogenous
signals. Endogenous nonlinear optics (NLO) signals are generally weak, unspecific
and usually require to improve the instruments detection threshold and to develop
R. Antoine (&)
Institut Lumière Matière, UMR5306 Université Claude Bernard Lyon1-CNRS,
Université de Lyon, 69622 Villeurbanne Cedex, France
e-mail: rodolphe.antoine@univ-lyon1.fr
© Springer Nature Switzerland AG 2019
A. Koleżyński and M. Król (eds.), Molecular Spectroscopy—Experiment
and Theory, Challenges and Advances in Computational Chemistry
and Physics 26, https://doi.org/10.1007/978-3-030-01355-4_5
139
Ligand-Core NLO-Phores
Two-Photon Absorption and Two-Photon
Excited Emission Properties of Atomically
Precise Clusters of Gold and Silver
Rodolphe Antoine
Abstract Functional ligand-protected noble metal cluster nanomaterials with
enhanced two-photon absorption and two-photon excited emission may lead to new
technologies for bio-imaging applications. In this article, I review experimental and
theoretical methodologies allowing detailed investigation of two-photon absorption/
emission properties of ligand-protected silver and gold metal clusters. This includes
femtosecond two-photon excited fluorescence experimental setups and quantum
chemical methodologies based on time-dependent density functional theory.
I thoroughly analyze physical phenomena and trends leading to large two-photon
absorption/emission responses of model nanoclusters focusing on the effects of the
relaxation pathways in the linear and nonlinear optical regime, as well as strategies
aiming at enhancing their two-photon emission responses.
5.1 Introduction
Recent developments in optical imaging techniques, in particular multi-photon
excitation (MPE) microscopy that allows studies of biological interactions at a deep
cellular level, have motivated intensive research in developing multi-photon
absorption fluorophores. Biological tissues are optically transparent in the
near-infrared region. Therefore, fluorophores that can absorb light in the NIR region
by multi-photon absorption are particularly useful in bio-imaging. MPE microscopy
enables molecular imaging by using either exogenous markers or endogenous
signals. Endogenous nonlinear optics (NLO) signals are generally weak, unspecific
and usually require to improve the instruments detection threshold and to develop
R. Antoine (&)
Institut Lumière Matière, UMR5306 Université Claude Bernard Lyon1-CNRS,
Université de Lyon, 69622 Villeurbanne Cedex, France
e-mail: rodolphe.antoine@univ-lyon1.fr
© Springer Nature Switzerland AG 2019
A. Koleżyński and M. Król (eds.), Molecular Spectroscopy—Experiment
and Theory, Challenges and Advances in Computational Chemistry
and Physics 26, https://doi.org/10.1007/978-3-030-01355-4_5
139