Enhanced nonlinear optical absorption and optical limiting properties of superparamagnetic spinel zinc ferrite decorated reduced graphene oxide nanostructures

Nanohybrids consisting of uniform nanospheres and nanospindles of zinc ferrite attached to reduced graphene oxide were prepared by hydrothermal reaction. Zinc ferrite decorated reduced graphene oxide exhibited enhanced nonlinear absorption, refraction and optical limiting (OL) action under continuous wave (532 nm, 50 mW) and ultrafast (800 nm, 150 fs) excitation. The enhancement can possibly be attributed to the synergistic effect stemming from the observed reverse saturable absorption and self-defocusing in the material. The role of defects in improving the nonlinear optical (NLO) performance of ZnFe2O4–rGO was explained with the aid of Raman spectroscopy and ground state absorption studies. Using fs and cw excitation, the estimated nonlinear absorption coefficient [γ3PA(fs) = 4.0 × 10−12 m W−1, β(cw) = 6.5 × 10−5 m W−1], nonlinear refractive index [n2(fs) = 4.2 × 10−18 m2 W−1, n2(cw) = 4.7 × 10−12 m2 W−1] and third order nonlinear optical (NLO) susceptibility [χ (3) (fs) = 1.9 × 10−15 esu, χ (3) (cw) = 4.2 × 10−6 esu] of nanospindle ZnFe2O4–rGO were found to be higher than those of its other counter parts. The estimated NLO parameters were found to be higher than those of other known OL materials such as functionalized hydrogen exfoliated graphene, CdO. Thus zinc ferrite decorated rGO nanostructures with proficient NLO coefficients have potential scope for utilizing them as smart materials for OL applications.

Improved third-order optical nonlinearity and optical limiting behaviour of (nanospindle and nanosphere) zinc ferrite decorated reduced graphene oxide under continuous and ultrafast laser excitation

The work presented here reported the effect of doping cobalt (Co) in ZnO thin films. The thin films were prepared using the spray pyrolysis technique with 0, 1, 5 and 10 wt% cobalt doping concentrations to study the morphological, optical and third-order nonlinear optical (NLO) properties. X-ray diffraction revealed the crystalline nature of the prepared thin films, and the crystallite size was found to increase with the concentration of doped Co. The morphology and surface topography of the films were largely influenced by doping, as indicated by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). With an increase in Co-doping concentration, the direct optical energy band-gap value increased from 3.21 eV to 3.45 eV for pure to 10 at% of Co concentrations respectively. To study the NLO properties of the prepared thin films, the Z-scan technique was adopted; it was observed that with an increase in the doping concentration from 0 to 10 wt%, the nonlinear absorption coefficient (β) was enhanced from 4.68 × 10−3 to 9.92 × 10−3 (cm W−1), the nonlinear refractive index (n2) increased from 1.37 × 10−8 to 2.90 × 10−8 (cm2 W−1), and the third-order NLO susceptibility (χ(3)) values also increased from 0.79 × 10−6 to 1.88 × 10−6 (esu). At the experimental wavelength, the optical limiting (OL) features of the prepared films were explored, and the limiting thresholds were calculated. The encouraging results of the NLO studies suggest that the Co : ZnO thin film is a capable and promising material for nonlinear optical devices and optical power limiting applications.

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The role of cobalt doping in tuning the band gap, surface morphology and third-order optical nonlinearities of ZnO nanostructures for NLO device applications

Investigations on the structural, morphological, linear and third order nonlinear optical properties of manganese doped zinc selenide nanoparticles for optical limiting application

Spectroscopic and thermal nonlinearity study of a Schiff base compound

Barium borate (?-BaB2O4) nanoparticles were prepared by a hydrothermal technique using barium chloride and boric acid as starting materials Powder x-ray diffraction confirms the pure single phase formation of ?-BaB2O4 Fourier transform infrared spectroscopy spectra shows the presence of BO3 units which extend themselves to form (B3O6)3? anionic groups in ?-BaB2O4 Scanning electron microscopy imaging shows the two-dimensional undulating particle surface with particle size in the range of 45?170?nm ?-BaB2O4 has strong absorption in the UV region and it possesses a wide optical transmittance window (201 to 1100?nm) The optical band gap of the ?-BaB2O4 nanoparticle is estimated to be 59?eV In the photoluminescence spectra the presence of self trapped excitonic state (347?nm) was identified The third order optical nonlinearity of the sample excited in two different pumping regimes, short pulse excitation (532?nm, 5?ns) and continuous wave laser (532?nm, 50?mW) was studied The material shows limiting behavior due to two photon absorption in the pulsed laser regime and self defocusing in the continuous wave regime

https://iopscience.iop.org/article/10.1088/0022-3727/48/6/065102/pdf

Optical limiting behavior of β-BaB2O4 nanoparticles in pulsed and continuous wave regime

Low temperature phase barium borate: A new optical limiter in continuous wave and nano pulsed regime

Excited state absorption assisted optical limiting action of Fe decorated γ-BBO nanorods

Genuine two photon absorption and excited state absorption in Fe nanowires decorated β-BaB2O4 nanoplatelets

Intensity-dependent nonlinear optical absorption and optical limiting behavior of Ni2+-doped (γ and β)-BaB2O4 nanostructures were examined by open-aperture Z-scan technique under nanosecond pulsed green laser excitation. Observation of reverse saturable absorption (RSA) with variation in nonlinear absorption coefficient as function of on-axis peak intensity ascertains the presence of sequential 2PA process (1PA + ESA). Due to the introduced near-resonant energy state through incorporation of Ni2+ ions, the material exhibits excited state absorption (ESA). Here, the observed sequential 2PA in Ni2+-doped γ-BaB2O4 involves the 1T1g(G) states of 3d8–3d8 and 1T1g(D) states of Ni2+, while Ni-doped β-BaB2O4 undergoes the electronic transition involving intraionic 3d8–3d8 transition of Ni2+ and self-trapped excitonic state of BBO. Interestingly, as the dopant concentration and on-axis intensity increased, 2PA coefficient was found to be increased. 0.05 M Ni2+-doped β-BaB2O4 nanostructures possess higher 2PA coefficient (2.31 × 10−10 m/W) and lower onset limiting threshold (0.79 × 1012 W/m2), which makes it a promising candidate for optical limiting applications. The result suggests that band structure tunability to induce excited state absorption with enhanced nonlinear absorption coefficient is possible through Ni doping in β-BaB2O4 nanostructures.

C. Babeela

Papers

Optical limiting behavior of β-BaB2O4 nanoparticles in pulsed and continuous wave regime

Low temperature phase barium borate: A new optical limiter in continuous wave and nano pulsed regime

Excited state absorption assisted optical limiting action of Fe decorated γ-BBO nanorods

Genuine two photon absorption and excited state absorption in Fe nanowires decorated β-BaB2O4 nanoplatelets

Facile synthesis, characterization and intensity-dependent nonlinear absorption of Ni-doped (γ and β)-BaB2O4 nanostructures