Photo-induced structured waves by nanostructured topological insulator Bi2Te3

Third-order nonlinear optical effects were proposed for simultaneous speed modulation of optical and mechanical waves in bismuth telluride nanostructures assisted by an optical two-wave mixing. The optical nonlinearities were investigated under excitation with nanosecond laser pulses at a wavelength of 532 nm. The Bi2Te3 nanostructures were prepared by a simple chemical process. Standard characterization by electrochemical impedance spectroscopy, ellipsometry, UV?Vis absorption and Fourier transform infrared spectrometry was undertaken. The phase purity and vibrational mode of the Bi2Te3 were determined by X-ray diffraction studies and Raman spectroscopy, respectively. The nanocrystal structure and morphology of the Bi2Te3 sample were identified by High-Resolution Transmission Electron Microscopy. The structural characterization and chemical composition of the nanostructures were carried out by Scanning Electron Microscopy combined with Energy Dispersive X-ray spectroscopy. The nanostructured nature of this topological insulator seems to be responsible of its unique polarization-selectable nonlinear optical response. Potential applications for developing structured light systems can be contemplated.