Two-photon absorption and optical-limiting properties of novel organic compounds

Abstract

The optical-limiting behavior and two-photon absorption properties of four novel organic compound solutions in tetrahydrofuran have been investigated. An ultrashort laser source with 0.5-ps pulse width and 602-nm wavelength was employed. The transmissivities of the various 1-cm-thick solution samples have been measured as a function of the beam intensity as well as of the solute concentration. The measured results can be fitted on the assumption that two-photon absorption is the only predominant mechanism causing the observed opticallimiting behavior. Based on the intensity-dependent transmissivity measurements, the molecular two-photon absorption coefficients for the four compounds are presented.

Enhanced Two‐Photon Absorption of Organic Chromophores: Theoretical and Experimental Assessments

“…Moreover, TPA can be induced at a frequency of half the actual energy gap which stretches the accessible range of conventional lasers (longer wavelengths at 700-1300 nm) and ensures deep penetration into scattering media. These distinct properties enable a large variety of improved and novel technological capabilities [7][8][9] such as spectroscopy, [10,11] fabrication of optoelectronic logical circuits, [12] microfabrication, [13][14][15][16] high-resolution fluorescence microscopy and characterization, [9,[17][18][19][20][21][22][23][24] three-dimensional optical data storage, [14,[25][26][27][28][29][30][31][32] optical power limiting, [33][34][35][36][37][38] upconversion lasing, [39][40][41][42] nondestructive imaging of biological tissues, [3,9,[43][44][45][46] photodynamic therapy, [47]…”

“…Thereby, attention has progressively moved from the well-known push-pull dipolar molecular structures [34,41,[75][76][77][78][79][80][81][82][83][84][85][86][87][88] to quadrupoles [3,33,36,57,58,63,76,78,81,85,86,[89][90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105][106][107] and, more recently, toward complex molecular architectures. Quadrupoles have been found to be more efficient than dipoles in terms of TPA, in particular for multiphoton-based opticallimiting applications.…”

General Optical-Limiting Requirements

“…Besides devices being engineered, materials are being molecularly tailored to fulfill the military's stringent requirements more effectively. Twophoton absorption materials are being developed with very large coefficients [15,16], and bichromophores are being designed with large nonlinear cross sections and much broader operating bandwidths [17]. The same is true of excited-state absorption dyes: work is being performed to increase their bandwidth, increase the excited-to-ground-state cross-section ratio, move the excited-state wavelength band, and even improve their solubility in nontoxic solvents [18][19][20].…”

A chemically labeled cytotoxic agent: Two-photon fluorophore for optical tracking of cellular pathway in chemotherapy

“…Twophoton laser-scanning microscopy (4 -7), introduced by Webb's group, has already been shown to be a powerful technique for probing the three-dimensional structure of a cell and to have inherent optical-sectioning capability without any significant interference from autofluorescence. Our recent efforts on design and synthesis of two-photon chromophores have produced highly efficient two-photon up-converters (which emit photons of a frequency higher than that of the absorbed photons); some of them even exhibit up-conversion lasing (8)(9)(10). In this paper, we report the synthesis of a two-photon fluorophore, which was coupled to a chemotherapeutic agent and used in optical tracking of its interaction and entrance in to the target cells by two-photon laser-scanning microscopy.…”