Experimental and theoretical investigation of linear and nonlinear optical properties of ethyl‐3‐hydroxy‐2‐napthoate azo dyes by solvatochromic, computational aspects, and Z‐scan technique

Abstract

To investigate the effect of substituents in azo dyes on their nonlinear optical properties, four azo dyes were synthesized using ethyl‐3‐hydroxy‐2‐naphthoate as a coupler and characterized. The polarizability (α) and hyperpolarizability (β and γ) constants were determined by using solvatochromic and computational method. A group of global hybrid and range seperated hybrid functionals having different Hartree‐Fock exchange percentage were used to evaluate the NLO properties. The functional ωB97 and ωB97XD performed better in the determination of polarizability (α) and hyperpolarizability (β and γ), respectively. The observed results for polarizability and hyperpolarizability parameters were supported by highest occupied molecular orbital‐lowest unoccupied molecular orbital (HOMO‐LUMO) energy gap, Hammett‐coefficient (σ), excited‐state coefficients (σex), and hyper‐hardness (Γ) values. Third‐order NLO properties were analyzed by using Z‐scan technique. The –OCH3 substituted dye 4d shows higher value of molecular susceptibility (χ(3)), polarizability (α), and hyperpolarizability (β and γ) parameters among the studied azo dyes. They are likely to have the potential applications in optoelectronics and photonics.

The Comparative Third‐Order Nonlinearities of Titanium Carbide and Tungsten Carbide in the Visible Regain

“…[12,13] The experimental details of the Z-scan technique can be found in Ref. [3]. In summary, the sample surface was targeted by a laser beam through a lens with a 19 cm focal length.…”

“…The experimental setup typically includes a laser source, focusing lens, a sample cell, and a detector. [3] In addition, the Z-scan technique was employed to detect the NLO characteristics of samples that was conducted using a continuous wave (CW) Nd:YAG diode laser at 532 nm wavelength. [28] The OA Z-scan experimental data revealed a decrease in transmittance and symmetric behavior approaching the beam focus (Z = 0), indicating reverse saturable absorption (RSA) behavior with a negative 𝛽 value.…”

“…The thermal nonlinearity responses were dominant in the TiC and WC nanoparticles, where continuous laser irradiation leads to localized heat generation and temperature-dependent refractive indices. [3,12] Figures 8 and 9 depicted the OA and CA experimental data of TiC and WC nanoparticles, respectively. Table 2 summarizes the NLO parameters obtained from the Z-scan analysis of TiC and WC nanoparticles.…”

“…Table 2 summarizes the NLO parameters obtained from the Z-scan analysis of TiC and WC nanoparticles. The followed-equations provided were used to calculate the NLO susceptibility of TiC and WC [30] : Re(𝜒 (3)…”

“…[2] Despite the availability of alternative materials for nonlinear optical devices, researchers are continuously searching for easily synthesized materials that offer enhanced optical nonlinearity. [3] One such material of interest is tungsten carbide (WC), which belongs to the MXene family. In WC, the interstitial sites of tungsten are filled with carbon atoms, resulting in the formation of a metal carbide compound.…”