Thermo-optic refraction in MoS2 medium for “Normally on” all optical switch

Abstract Two dimensional (2D) nanomaterials like Molybdenum disulfide (MoS2) have been drawing a lot of interest due to their excellent nonlinear optical response. In this research we study thermal lens formation in MoS2 nanoflakes dispersion using mode mismatched pump probe configuration. Observation of the pump and probe beam intensity patterns gave visual insights on time evolution of photothermal lens formation. Effect of MoS2 nanoflakes concentration on thermo-optic properties of dispersions were studied using thermal lens spectroscopy technique. Further, a thermo-optic refraction based technique to measure thermal lens size is proposed. Thermal lens region size increased with increase in pump power. The observed thermal lens modulation is applied to demonstrate ‘normally on’ all optical switch which showed excellent modulation of output beam signal by pump beam.