scholarly journals Photoconductive Multiplexing by ZnO:Zr:F Thin Solid Films

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
C. Torres-Torres ◽  
L. Castañeda ◽  
R. Torres-Martínez

Within this work, the nonlinear optical properties and electrical effects exhibited by zinc oxide thin films codoped with zirconium and fluorine are reported. The development of a simple photoconductive multiplexor system is proposed. The samples were prepared by the ultrasonic spraying technique (UST). Spectroscopic studies and a vectorial two-wave mixing method were carried out with a nanosecond Nd:YAG laser system at 532 nm. Experimental results indicate that after the zirconium and fluorine doping, a strong third-order optical nonlinearity can be developed in the ZnO films. The nonlinear optical response seems to be dominantly originated by a two-photon absorption closely related to a photoconductive phenomenon.

2001 ◽  
Vol 10 (01) ◽  
pp. 65-77 ◽  
Author(s):  
OU FA ◽  
HE MINGGAO ◽  
WU FUGEN

A new model to describe the origin of optical nonlinearity is presented. In this model, the interaction between light and medium is reduced to the coupling of photons with phonons, which occurs in the crystal lattice vibrating anharmonically. Then the optical nonlinearity originates from the nonlinear photon–phonon coupling or the interaction among phonons themselves. In this paper, more attention is drawn to the latter. By the given model, (1) degenerate and (2) nondegenerate parametric oscillations, (3) Stokes and (4) anti-Stokes Raman scattering, (5) sum-frequency and (6) second harmonic generation and (7) two-photon absorption are dealt with systematically and quantum-mechanically. The results of theoretical analysis show that the effects (1)–(4) are associated with threshold phenomenon, whereas the effects (5)–(7) with the saturation phenomenon.


Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1670
Author(s):  
Jan K. Zaręba ◽  
Marcin Nyk ◽  
Marek Samoć

Nonlinear optical (NLO) pigments are compounds insoluble in solvents that exhibit phenomena related to nonlinear optical susceptibilities (χ(n) where n = 2,3,...), e.g., two-photon absorption (2PA) which is related to the imaginary part of χ(3). Determination of spectrally-resolved 2PA properties for NLO pigments of macromolecular nature, such as coordination polymers or crosslinked polymers, has long been a challenging issue due to their particulate form, precluding characterizations with standard techniques such as Z-scan. In this contribution, we investigate thus far unknown spectrally-resolved 2PA properties of a new subclass of NLO pigments—crosslinked conjugated polymers. The studied compounds are built up from electron-donating (triphenylamine) and electron-withdrawing (2,2’-bipyridine) structural fragments joined by vinylene (Pol1) or vinyl(4-ethynylphenyl) (Pol2) aromatic bridges. 2PA properties of these polymers have been characterized in broad spectral range by specially modified two-photon excited fluorescence (TPEF) techniques: solid state TPEF (SSTPEF) and internal standard TPEF (ISTPEF). The impact of self-aggregation of aromatic backbones on the 2PA properties of the polymers has been evaluated through extended comparisons of NLO parameters, i.e., 2PA cross sections (σ2) and molar-mass normalized 2PA merit factors (σ2/M) with those of small-molecular model compounds: Mod1 and Mod2. By doing this, we found that the 2PA response of Pol1 and Pol2 is improved 2–3 times versus respective model compounds in the solid state form. Further comparisons with 2PA results collected for diluted solutions of Mod1 and Mod2 supports the notion that self-aggregated structure contributes to the observed enhancement of 2PA response. On the other hand, it is clear that Pol1 and Pol2 suffer from aggregation-caused quenching phenomenon, well reflected in time-resolved fluorescence properties as well as in relatively low values of quantum yield of fluorescence. Accordingly, despite improved intrinsic 2PA response, the effective intensity of two-photon excited emission for Pol1 and Pol2 is slightly lower relative to Mod1 and Mod2. Finally, we explore temperature-resolved luminescence properties under one- (377 nm), two- (820 nm), and three-photon excitation (1020 nm) conditions of postsynthetically Eu3+-functionalized material, Pol1-Eu, and discuss its suitability for temperature sensing applications.


2019 ◽  
Vol 5 (6) ◽  
pp. eaaw3262 ◽  
Author(s):  
Gustavo Grinblat ◽  
Michael P. Nielsen ◽  
Paul Dichtl ◽  
Yi Li ◽  
Rupert F. Oulton ◽  
...  

Gallium phosphide (GaP) is one of the few available materials with strong optical nonlinearity and negligible losses in the visible (λ > 450 nm) and near-infrared regime. In this work, we demonstrate that a GaP film can generate sub–30-fs (full width at half maximum) transmission modulation of up to ~70% in the 600- to 1000-nm wavelength range. Nonlinear simulations using parameters measured by theZ-scan approach indicate that the transmission modulation arises from the optical Kerr effect and two-photon absorption. Because of the absence of linear absorption, no slower free-carrier contribution is detected. These findings place GaP as a promising ultrafast material for all-optical switching at modulation speeds of up to 20 THz.


2002 ◽  
Vol 209 (4-6) ◽  
pp. 461-466 ◽  
Author(s):  
I. Fuks-Janczarek ◽  
J-M. Nunzi ◽  
B. Sahraoui ◽  
I.V. Kityk ◽  
J. Berdowski ◽  
...  

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