Intensity dependent nonlinear absorption switching behavior of electrospun meta-nitroaniline nanofiber

Abstract

The present work reports the study on nonlinear absorbing behavior of optically nonlinear m-nitroaniline (mNA) organic molecules properly oriented in the core of a polymeric fiber such as Poly (methyl methacrylate) (PMMA) and Poly (ethylene Oxide) (PEO) free standing films synthesized by electrospinning technique for the first time. The nonlinear absorption nature of the nanofibers is investigated by intensity dependent Z scan technique (532 nm, 10 Hz, 5ns). We observed an unusual nonlinear switching behavior in mNA- PMMA nanofiber from reverse saturable absorption (RSA) to saturable absorption (SA) through a peculiar W-pattern for an increase in pulse energy, whereas intensity dependent SA behavior is seen clearly in mNA–PEO polymer matrix. The identified nonlinear absorption of mNA –PMMA and mNA -PEO fibers can be of interest for various optical applications such as switching, optical sensors, etc. The normalized transmittance versus input fluence graph confirms the potential possibility of using the prepared fibers as optical switches at higher intensity. And mNA – PMMA fiber matrix at low intensities exhibits an optical limiting behavior, implying that the material to be a potential candidate for laser safety devices. Demonstrated fiber matrix free standing films are of potential use as it finds direct application in laser photonic devices.