Numerical Study of Light Guiding Nanostructures Based on Non-van-der-Waals InGaS₃

For the development of integrated optical circuits novel approaches aimed at miniaturization of the solutions are needed. For this, materials possessing high optical density and allowing feasible fabrication are demanded. Among the promising materials InGaS₃ demonsrating optical anisotropy and high refractive index is one of the interesting platforms. In this work we investigate the effects of InGaS₃ strip and slot waveguides geometry on their optical properties. We use numerical simulations to investigate square, rectangle and slot waveguides and evaluate the influence of their longitudinal and lateral size on eigenmodes field distribution, optical losses and transmittance spectra. For strip waveguides we obtain the design of square, rectangle TE and TM cross-section geometry below the waveguiding cut-off (∼70–100 nm), single- (∼120–250 nm) and multimode regime (>250 nm). For the slot waveguides the gap modes were calculated for 505 nm wavelength varying gap values. Transmittance spectra demonstrate dependence on the gap size which allows to develop the bandpass or long-pass optical filters. The obtained results open pathways for fabrication of promising photonic devices based on InGaS₃ thin layers.