Linear Dichroism Conversion in Quasi One-Dimensional Perovskite Chalcogenide

TL;DR

This study reports a novel linear dichroism conversion phenomenon in quasi-one-dimensional BaTiS3, enabling orthogonal polarization changes at specific wavelengths, with potential applications in advanced photonic devices.

Contribution

The paper demonstrates the first observation of linear dichroism conversion in a crystalline material, revealing unique optical behavior in BaTiS3 due to its electronic transition rules.

Findings

BaTiS3 exhibits record optical anisotropy in visible wavelengths.

Linear dichroism polarity in BaTiS3 changes orthogonally at 1.78 eV.

First principle calculations explain the dichroism conversion mechanism.

Abstract

Anisotropic photonic materials with linear dichroism are crucial components in many sensing, imaging and communication applications. Such materials play an important role as polarizers, filters and wave-plates in photonic devices and circuits. Conventional crystalline materials with optical anisotropy typically show unidirectional linear dichroism over a broad wavelength range. The linear dichroism conversion phenomenon has not been observed in crystalline materials. Here, we report the investigation of the unique linear dichroism conversion phenomenon in quasi-one-dimensional (quasi-1D) hexagonal perovskite chalcogenide BaTiS3. The material shows record level of optical anisotropy within the visible wavelength range. In contrast to conventional anisotropic optical materials, the linear dichroism polarity in BaTiS3 makes an orthogonal change at an optical wavelength corresponding to the photon energy of 1.78 eV. First principle calculations reveal that this anomalous linear dichroism conversion behavior originates from different selection rules of the optical transitions from the parallel bands in the BaTiS3 material. Wavelength dependent polarized Raman spectroscopy further confirms this phenomenon. Such material with linear dichroism conversion property can facilitate new ability to control and sense the energy and polarization of light, and lead to novel photonic devices such as polarization-wavelength selective detectors and lasers for multispectral imaging, sensing and optical communication applications.