Study of linear and non-linear optical responses of MoSe2–PMMA nanocomposites

Abstract

MoSe2 material has been synthesized by the hydrothermal technique. Further, MoSe2/PMMA polymer nanocomposites have been synthesized to study their effect on structural and optical properties on varying concentrations of MoSe2 nanoparticles (NPs). X-ray diffraction (XRD) depicts the uniform distribution of NPs in the PMMA matrix. The small crystallites are observed at different spots at higher concentration. UV–Vis spectroscopy revealed the presence of saturable absorption as the bandgap decreases with an increase in the concentration of MoSe2. Also, the formation of aggregates at a high concentration of MoSe2 is observed in FESEM images. FT-IR studies confirmed the complete dispersion of NPs in the PMMA matrix. Non-linear optical study of samples is done using the Z-scan experimental technique. Saturable absorption (SA) and the self-defocusing effect are observed in the prepared nanocomposites. The non-linear refractive index (n2) increases to the order of 10−6cm2/W along with the rise in non-linear absorption coefficient (β) up to ~ 10−7 cm/W. There is a disclosure of a huge upsurge in third-order susceptibility with an increase in the concentration of MoSe2 NPs in PMMA host. The results clearly put the accent on the possibility of tuned optical non-linearity of MoSe2–PMMA nanocomposites by varying nanoparticle concentrations. Based on the saturable absorption properties, this material has great potential for the development of various optoelectronic applications such as the generation of short laser pulses and saturable absorbers.