Dispersive optical nonlinearities and optical path length compensation in NiO/Al doped NiO bilayer thin film

• Published in: Optical materials 2019-10, Vol.96, p.109278, Article 109278
• Main Authors: Baraskar, Priyanka, Choudhary, Ram Janay, Sen, Pranay Kumar, Sen, Pratima
• Format: Article
• Language: English
• Subjects: Dispersive optical nonlinearities; Optical path length compensation; Photoexpansion and photodensification
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2019.109278

Dispersive optical nonlinearities in pulsed laser deposited undoped and 5% Al doped NiO thin films reveal negative and positive optical nonlinearities, respectively. The cause of optical nonlinearity is assigned to the presence (absence) of oxygen vacancies in undoped NiO (5% Al doped NiO) thin film which leads to photodensification (photoexpansion) and gives rise to thermo-optic effect. Quite interestingly, the observation of opposite kinds of nonlinearities in a NiO/Al doped NiO bilayer film, leads to the neutralization of the dispersive optical nonlinearity and one expects a resultant optical path length compensation. •Dispersive optical nonlinearities in pulsed laser deposited undoped and 5% Al doped NiO has been studied.•Undoped NiO shows negative dispersive optical nonlinearity and indicate self-defocusing effect.•5% Al doped NiO displays positive dispersive optical nonlinearity which suggests self-focussing effect.•The cause of dispersive optical nonlinearities is assigned to the thermal lensing effect.•NiO/AlNiO shows athermal lensing effect and suggest its application in optical path length compensation.