Title

Experimental And Theoretical Approaches To Understanding Two-Photon Absorption Spectra In Polymethine And Squaraine Molecules

Abstract

We performed a detailed experimental investigation and quantum-chemical analysis of two-photon absorption (2PA) spectra of a series of symmetrical cationic polymethines and neutral squaraines having similar structures. Degenerate 2PA spectra of these molecules are taken by using two-photon fluorescence spectroscopy and the Z-scan technique. All measurements are made with 150 fs laser pulses of 1 kHz repetition rate in the tuning range of 520-2100 nm (0.6-2.4 eV). Comparing 2PA spectra of polymethines and squaraines, we find that we can access considerably larger 2PA cross sections (≥8600 × 10-50 cm4 s/photon) in the squaraines owing to narrower linear absorption spectra and an increase in the density of unoccupied molecular orbitals introduced by the squaraine acceptor group in the conjugated chain. © 2006 Optical Society of America.

Publication Date

1-1-2007

Publication Title

Journal of the Optical Society of America B: Optical Physics

Volume

24

Issue

1

Number of Pages

67-76

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1364/JOSAB.24.000067

Socpus ID

33846985994 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/33846985994

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