Three‐dimensional visualization of the first hyperpolarizability tensor

Abstract

With polarization dependent second harmonic generation (SHG) microscopy becoming a more popular method for investigating the structure of biological materials, there is a need to develop tools with which to understand and interpret the observed SHG properties. Quantum mechanical calculations of the hyperpolarizability tensor have become a popular method for understanding the SHG properties of biomolecules. Visualization of the full hyperpolarizability tensor, termed the unit sphere representation, has been developed to provide insight and intuition on the relationship between SHG properties and molecules. A single vector representation is also presented, which approximates the SHG properties of molecules for certain cases, where the anisotropy is negligible.

Characterization of collagen in non-small cell lung carcinoma with second harmonic polarization microscopy

“…Differences in susceptibility ratio can originate from the three structural hierarchy levels in collagen and this appears to be affected in tumor tissue. Thus, differences in the amino acid composition of collagen can alter the susceptibility ratio of triple helices [9]. In turn, the triple helices can assemble parallel or they can coil into fibrils with a specific helical pitch, which also influences the susceptibility component ratio [10].…”

Structure of Collagen in Lung Carcinoma Tissue Characterized with Harmonic Polarization Microscopy

“…In the next level of hierarchical structure of collagen, the triple helices assemble to form larger fibrils [13]. Differences in susceptibility ratio can originate from three structural alterations in collagen due to tumor progression: (i) the amino acid composition of the collagen triple helices [17,18], (ii) the arrangement of triple helices in the fibrils, and (iii) orientational alteration of the fibrils in the fiber structure. Further biochemical investigations are needed to determine the nature of collagen structural changes.…”

How Dimerization Through a Spiro Junction Modifies the Nonlinear Optical Properties of a Push–Pull Organic Dye: Insights from Theory and Hyper‐Rayleigh Scattering

“…[25] Quantum chemical calculations were performed using the Gaussian 09 package. [26] To provide insight on the relationship between SHG properties and molecular shapes, the unit sphere representation [27] is used to visualize the first hyperpolarizability tensor.T his method is based on the computation of an effective induced SHG dipole (m eff )d efined as [Eq. www.chemphotochem.org sible incident polarizations defined by q; f ðÞ ,au nit sphere is mapped out.…”