Nonlinear Optical Materials: Predicting the First-Order Molecular Hyperpolarizability of Organic Molecular Structures

Abstract

Experimental nonlinear optics (NLO) is usually expensive due to the high-end photonics and electronic devices needed to perform experiments such as incoherent second harmonic generation in liquid phase, multi-photon absorption, and excitation. Nevertheless, exploring NLO responses of organic and inorganic compounds has already opened a world of new possibilities. For example, NLO switches, NLO frequency converters, and a new way to obtain biological images through the incoherent second harmonic generation (SHG) originate from first-order molecular hyperpolarizability (β). The microscopic effect of the coherent or incoherent SHG is, in fact, the β. Therefore, estimating β without using expensive photonic facilities will optimize time- and cost-efficiency to predict if a specific molecular structure can generate light with double its incident frequency. In this work, we have simulated the β values of 27 organic compounds applying density functional theory (PBE0, TPSSh, wB97XD, B3LYP, CAM-B3LYP, and M06-2X) and Hartree–Fock methods using the Gaussian software package. The predicted β was compared with the experimental analogs obtained by the well-known Hyper–Rayleigh Scattering (HRS) technique. The most reliable functionals were CAM-B3LYP and M06-2X, with an unsigned average error of around 25%. Moreover, we have developed post-processing software—Hyper-QCC, providing an effortless, fast, and reliable way to analyze the Gaussian output files.

Pseudo-Stilbene- and Azobenzene-Type Systems for Optical Frequency Conversion: Estimating the First-Order Molecular Hyperpolarizability

“…The computational methodology consisted of three steps: molecular structure geometry optimization, calculating the one-photon vertical excitation energies, and computing the tensor components of the first-order molecular hyperpolarizability. Then, Hyper-QCC [19], a post-processing software dedicated to computing third-order ranking tensor components in a fast and reliable way, was used for the final calculation of β 0 and β HRS values.…”

“…The post-processing software Hyper-QCC [19] calculates the first-molecular hyperpolarizability based on the mixed spherical-cartesian formalism [59], in which the orientational averaged first-order hyperpolarizability squared β HRS is expressed by Equation ( 1) [60].…”

“…This timeframe encompasses the entire spectrum of tasks, from molecular design and optimization to the post-processing of the resulting QCC data. Naturally, the duration can vary based on the chosen theoretical level, as noted in reference [19].…”

“…Also, we have used the most common wavelengths in the field of optical communications (λ = 1064 nm, 1310 nm, and 1550 nm) to establish an empirical correlation for future OFC development. Therefore, in this work, QCCs were carried out at the time-dependent density functional theory (TD-DFT) level to estimate the influence of functional groups on the magnitude of the β HRS using Gaussian 16 and Hyper-QCC [19], which is post-processing software.…”

Styrene monomer as potential material for design of new optoelectronic and nonlinear optical polymers: density functional theory study

“…Hyper-Rayleigh scattering (HRS) is one of the experimental techniques used to measure the intensity of the incoherently scattered frequency-doubled light generated after the interaction of a laser beam with a chromophore in an isotropic solution [99]. As optical communication networks evolve, the research and development of new compounds with NLO performance is of significant importance for improving this field [100,101].…”