  Two dimensional nanomaterials like Molybdenum disulfide 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.
