Resonant enhancement of third‐order nonlinear optical property in J‐like aggregates of a cyanine dye

Abstract

The wavelength dependence of the third-order optical nonlinearity and response of the J-like aggregates of a cyanine dye called NK-3261 in a neat film were measured by the femtosecond degenerate four-wave mixing (DFWM) technique under resonant conditions. The temporal profile of the DFWM signal of NK-3261 J-like aggregates was found to consist of three components, i.e., coherent instantaneous nonlinear response (electronic response) and the two slow responses with decay time constants of ca. 0.9 ps and ca. 5.6 ps. The electronic component of the effective third-order nonlinear optical susceptibility, (3) e χ , of NK-3261 J-like aggregates was as high as ca. 5 × 10 -7 esu at 850 nm.

Effects of Dendronization on the Linear and Third-Order Nonlinear Optical Properties of Bis(thiopyrylium) Polymethine Dyes in Solution and the Solid State

“…It is well-known that cyanine chromophores are inherently highly polarizable and are, therefore, prone to aggregation at high concentrations, leading to the formation of dimers or other aggregates with various relative orientations of molecules, that is, H- or J-aggregates (with parallel long axes and a face-to-face arrangement or end-to-end arrangement, respectively) or oblique arrangements of chromophores. The intermolecular electronic interactions lead to a mixing of the excited state wave functions that can result in a splitting (for inclined or oblique dimers), or a hypsochromic shift (for H-aggregates) or bathochromic shift (for J-aggregates) of the electronic absorption band relative to what is seen for isolated molecules in dilute solutions. ,− Such changes in the absorption spectrum could have adverse effects on the macroscopic properties of materials derived from these dyes. In particular, a hypsochromic shift could lead to decreased χ (3) relative to that expected from the solution values of γ for isolated molecules and a bathochromic shift, while potentially augmenting the macroscopic nonlinearity, could lead to increased linear losses at the operating wavelengths.…”

Bisdioxaborine Polymethines with Large Third-Order Nonlinearities for All-Optical Signal Processing

“…Compound 2 exhibited good solubility in DMSO, permitting solution processing and fabrication of neat solid films, which is crucial to obtain the high bulk nonlinearities required for AOSP applications. The absorption spectrum of a neat film of 2 (shown in Figure ) exhibits a broadening and splitting of the band compared to the solution spectrum, most likely due to excitonic effects upon aggregate formation; yet the film still maintains relatively low linear absorption for wavelengths greater than 1.35 μm. With the use of degenerate four-wave mixing and Z-scan methods, the third-order macroscopic nonlinearity, χ (3) , was determined for the film.…”

Nonlinear optical properties of natural laccaic acid dye studied using Z-scan technique

“…This could be the most important mechanism of the nonlinearity in the closed aperture (CA) Z-scan experiments. The current n 2 values are generally of one to two orders of magnitude than the value reported for the ferrocene-porphyrin derivatives including phenylhydrazone derivatives [34] and, 10 4 times larger than that of the reported values for photorefractive crystals, liquid crystals, and Benzo[a]phenoxazinium salts [35][36][37]. As illustrated in Table 2, there is a global increasing trend for the values of n 2 as the concentration increases.…”