Switching of absorptive nonlinearity from reverse saturation to saturation in polymer-ZnO nanotop composite films

Abstract

We report an interesting switchover of optical nonlinearity from Reverse Saturable Absorption (RSA) to Saturable Absorption (SA) in polymer-Zinc Oxide (ZnO) nanotop composite films, investigated using the Z-scan technique. The nanocomposites have been prepared by in situ polymerization of the monomer in which ZnO nanotops are dispersed with the help of a dispersing agent. The films exhibit RSA for lower concentrations of ZnO nanotops, which changes to SA on increasing the loading concentration, irrespective of the monomer and dispersing agent used. These versatile films are good candidates for applications such as ultrafast optical switching and optical limiting.

Enhanced blue light emission in transparent ZnO:PVA nanocomposite free standing polymer films

“…Flexible polymeric materials which emit blue light are interested in future optics based technology [8][9][10][11][12]. Incorporation of nanomaterials in polymers makes a new class of materials which have versatile properties and show potential ability in various fields like flexible light emitters [13,14], magnetic storage [15], energy storage [16] and optical power limiters [17]. Among the polymers, poly vinyl alcohol (PVA) is an eco-friendly, water soluble and easily film forming nature at room temperature, which shows good host behaviour.…”

Fumed SiO2 nanoparticle reinforced biopolymer blend nanocomposites with high dielectric constant and low dielectric loss for flexible organic electronics

“…The integration of inorganic nanoparticles into a polymer matrix combines the properties of both inorganic nanoparticles and the polymer and thus generates advanced and new functions for the polymer nanocomposites . Inorganic nanoparticle–filled polymer nanocomposites have potential applications in various fields, such as flexible light emitters, energy storage, magnetic storage, membranes for gas separation, and optical power limiters . The final properties of these polymer nanocomposites depend on the properties of the individual phases, their relative contents, and the geometry of the dispersed phase (shape, size, and orientation of the inorganic nanoparticles) .…”

“…4,5 Inorganic nanoparticle-filled polymer nanocomposites have potential applications in various fields, such as flexible light emitters, energy storage, magnetic storage, membranes for gas separation, and optical power limiters. [6][7][8][9][10][11] The final properties of these polymer nanocomposites depend on the properties of the individual phases, their relative contents, and the geometry of the dispersed phase (shape, size, and orientation of the inorganic nanoparticles). 12 With this renewed interest in nanocomposites, researchers began seeking new strategies to engineer materials that can combine the desirable properties of nanoparticles and of polymers for the formation of polymer nanocomposites.…”

A few-picosecond and high-peak-power passively mode-locked erbium-doped fibre laser based on zinc oxide polyvinyl alcohol film saturable absorber

“…The results of this investigation revealed that the nonlinear absorption of ZnO is due to the two-photon resonance at the band edge and exciton energy level while the optical nonlinearity is induced by the free carrier [29]. Another investigation into the optical nonlinearity of ZnO using the same method showed a switchover from reverse saturable absorption to saturable absorption, which is an interesting characteristic for an ultrafast optical switching application [30]. Furthermore, ZnO has a high third-order nonlinear coefficient.…”