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Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection
Published on: October 13, 2017
Remarkable two-photon absorption in open-shell singlet systems.
Masayoshi Nakano1, Kyohei Yoneda, Ryohei Kishi
1Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan. mnaka@cheng.es.osaka-u.ac.jp
The Journal of Chemical Physics
|September 26, 2009
Summary
Open-shell singlet diradicals with intermediate diradical character show enhanced two-photon absorption (TPA) peaks. These systems, particularly those with ferromagnetic coupling, exhibit superior nonlinear optical properties compared to closed-shell analogs.
Area of Science:
- Theoretical Chemistry
- Materials Science
- Nonlinear Optics
Background:
- Two-photon absorption (TPA) is a key nonlinear optical phenomenon.
- Diradical systems offer unique electronic properties.
- Understanding structure-property relationships is crucial for designing advanced materials.
Purpose of the Study:
- To theoretically investigate TPA in open-shell singlet diradical systems.
- To compare TPA enhancement in systems with varying diradical character.
- To identify design principles for molecules with superior nonlinear optical responses.
Main Methods:
- Theoretical calculations of TPA cross-sections.
- Analysis of electronic structure and excited states.
- Systematic variation of diradical character and coupling.
Main Results:
- Symmetric open-shell singlet diradicals with intermediate diradical character exhibit significantly enhanced TPA peaks.
- Largest TPA intensities are observed in ferromagnetically coupled diradicals.
- TPA enhancement is sensitive to the ratio of damping factors in excited states.
Conclusions:
- Open-shell singlet diradicals with intermediate diradical character are promising for advanced nonlinear optical applications.
- These systems outperform conventional closed-shell conjugated molecules in resonant third-order nonlinear optics.
- Molecular design focusing on diradical character and magnetic coupling can optimize TPA properties.
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