Large Nonlinear Refraction and Higher Order Nonlinear Optical Effects in a Novel Organic Dendrimer

Abstract

The fast electronic nonlinear optical (NLO) properties of a novel synthetic organic dendrimer are reported. The complete synthesis of the organic dendrimer is provided. Both the z-scan and self-phase modulation techniques were used to measure the nonlinear refractive index. The magnitude of the nonlinear refractive index (n 2) was measured to be 1.1 × 10 - 4 cm2/GW. The presence of two-photon absorption was observed and the coefficient (β) was found to be 1.2 × 10-2 cm/GW. The nonlinear figure of merit of the dendrimer system is found to be 0.02 for intensities used in our experiments. The NLO responses of the individual structural components of the dendrimer molecule are provided to probe the structure−function relationships. The presence of a higher order, χ(5), NLO effect was also detected and analyzed. The fast electronic processes of the dendrimer molecule and its components where also investigated by up-conversion luminescence spectroscopy. These studies provide the first probe into the ultrafast electronic NLO effects in organic dendrimers.

Ultrafast polarized fluorescence dynamics in an organic dendrimer

“…Synthesis and spectroscopic features of all the structures have been described elsewhere. 8,14 The p-bis͑o-methylstyryl͒-benzene ͓bis-MSB͔ chromophore was used as a model compound for investigations of intermolecular interactions in A-DSB. Solutions in chloroform were used in this study.…”

“…Optical arrangement for the upconversion experiments has been described previously. [14][15][16] The sample was excited with laser pulses delivered by a frequency doubled output of the Ti:sapphire laser ͑Tsunami, Spectra Physics͒. The laser with an average pulse width of 100 fs tuned at 790-860 nm and a repetition rate of 82 MHz beam was controlled using Berek compensator.…”

Femtosecond luminescence dynamics in a nonlinear optical organic dendrimer

“…It is also interesting to note that the fast nonlinear response was found to be the same for NS1 and CZD4NSC2. 6 From all these results it can be concluded that the complex fluorescence dynamics shown in Figs. 3 and 4 ͑the long-lived decay and the rise-time components͒ is not connected with the formation of excited-state aggregates ͑excimers or exciplexes͒, as was observed for another type of dendrimer molecule composed of phenylene building blocks.…”

“…14 The optical arrangement for the upconversion experiments was described previously. 6,15 The laser source was a Ti:sapphire laser with an average pulse width of 100 fs tuned at 790-860 nm, and a repetition rate of 82 MHz ͑Tsunami, Spectra Physics͒. The sample was excited with light pulses delivered by a frequency-doubled output of the laser at 395-430 nm.…”

“…1 Dendrimers have received increasing attention due to their interesting electronic properties and their potential applications. [1][2][3][4][5][6][7] The nature of optical excitations in dendrimers is still a matter of debate. It has been suggested that after excitation the electron ͑and hole͒ is localized on linear segments of the dendrimer.…”