Tuned intensity-dependent refractive index n2 and two-photon absorption in oxide glasses: Role of non-bridging oxygen bonds in optical nonlinearity

2008 ◽  
Vol 31 (2) ◽  
pp. 161-166 ◽  
Author(s):  
Fouad El-Diasty ◽  
Manal Abdel-Baki ◽  
F.A. Abdel-Wahab
Keyword(s):  
Refractive Index ◽  
Optical Nonlinearity ◽  
Photon Absorption ◽  
Oxide Glasses ◽  
Two Photon Absorption ◽  
Two Photon

OPTICAL NONLINEARITY VIA PHONONS AS AN INTERMEDIARY

2001 ◽  
Vol 10 (01) ◽  
pp. 65-77 ◽  
Author(s):  
OU FA ◽  
HE MINGGAO ◽  
WU FUGEN
Keyword(s):  
Second Harmonic ◽  
Optical Nonlinearity ◽  
Photon Absorption ◽  
Saturation Phenomenon ◽  
Sum Frequency ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Threshold Phenomenon ◽  
Anti Stokes ◽  
The Given

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.

scholarly journals Ultrafast sub–30-fs all-optical switching based on gallium phosphide

2019 ◽  
Vol 5 (6) ◽  
pp. eaaw3262 ◽  
Author(s):  
Gustavo Grinblat ◽  
Michael P. Nielsen ◽  
Paul Dichtl ◽  
Yi Li ◽  
Rupert F. Oulton ◽  
...  
Keyword(s):  
Gallium Phosphide ◽  
Optical Switching ◽  
Near Infrared ◽  
Optical Nonlinearity ◽  
Photon Absorption ◽  
Linear Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
All Optical ◽  
All Optical Switching

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.

OPTICAL LIMITING STUDIES IN PHOTOREFRACTIVE PURE AND IRON-DOPED Bi12SiO20 CRYSTALS

2000 ◽  
Vol 09 (02) ◽  
pp. 217-225 ◽  
Author(s):  
P. SREERAMANA AITHAL ◽  
P. PREM KIRAN ◽  
D. NARAYANA RAO
Keyword(s):  
Excited State Absorption ◽  
Optical Limiting ◽  
Photon Absorption ◽  
Limiting Behavior ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Iron Incorporation ◽  
Optical Limiter ◽  
Level Model

Optical limiting characteristics of pure and 150 ppm Fe-doped Bi 12 SiO 20 (BSO:Fe) crystals are studied at high intensity nanosecond pulse regime. When the input light is at 532 nm and at 595 nm with 6 ns pulse duration, a good optical limiting behavior is observed due to simultaneous effect of trap assisted excited state absorption and two photon absorption. The precise role of the internal defects due to impurity centers present in the crystal lattice is explained on the basis of a four level model. This study reveal that the increased nonlinear absorption due to iron incorporation in BSO makes it an excellent passive optical limiter.

scholarly journals The Influence of Quantum Confinement on Third-Order Nonlinearities in Porous Silicon Thin Films

2018 ◽  
Vol 8 (10) ◽  
pp. 1810 ◽  
Author(s):  
Rihan Wu ◽  
Jack Collins ◽  
Leigh Canham ◽  
Andrey Kaplan
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Quantum Confinement ◽  
Nonlinear Refraction ◽  
Photon Absorption ◽  
Third Order ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Silicon Thin Films ◽  
Gaussian Decomposition

We present an experimental investigation into the third-order nonlinearity of conventional crystalline (c-Si) and porous (p-Si) silicon with Z-scan technique at 800-nm and 2.4- μ m wavelengths. The Gaussian decomposition method is applied to extract the nonlinear refractive index, n 2 , and the two-photon absorption (TPA) coefficient, β , from the experimental results. The nonlinear refractive index obtained for c-Si is 7 ± 2 × 10 − 6 cm 2 /GW and for p-Si is − 9 ± 3 × 10 − 5 cm 2 /GW. The TPA coefficient was found to be 2.9 ± 0.9 cm/GW and 1.0 ± 0.3 cm/GW for c-Si and p-Si, respectively. We show an enhancement of the nonlinear refraction and a suppression of TPA in p-Si in comparison to c-Si, and the enhancement gets stronger as the wavelength increases.

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