scholarly journals Aspect-ratio Dependence of Optical Nonlinearities on Resonance with Longitudinal Surface Plasmon in Au Nanorods: Unique Character versus Common Behavior

2018 ◽  
Vol 1 (1) ◽  
pp. 001-007
Author(s):  
Science Nature
Keyword(s):  
Aspect Ratio ◽  
Surface Plasmon ◽  
Nonlinear Behavior ◽  
Dipole Approximation ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Optical Nonlinearities ◽  
Ratio Dependence ◽  
Unique Character ◽  
Metal Metal

Unique character and common behavior are two distinguished things. In frontier nanoscience and nanotechnology, unique characters were normally obtained in some novel exotics materials such as metal-metal core-shell materials, metallic-semiconducting hybrid nanomaterials, and  organic-inorganics complex nano-compounds. On the other hand, normal behavior of natural phenomena including in nano-size objects were obviously predicted based on their exact size related to confinement effect, and capability to interact with another physical system  in nature.  Here, we report an example of unique character due to evolution nonlinear behavior observed in gold nanorod with their aspect-ratio dependence of optical nonlinearities investigated by femtosecond Z-scan measurements closed to resonance longitudinal surface plasmon peak in gold nanorods (Au NRs). Saturable absorption manifests itself at low excitation (laser irradiances < ~7.0 GW/cm2), while reverse saturable absorption dominates at higher excitation. Both the nonlinear processes are found to increase with the aspect ratio of Au NRs.  Based on the discrete dipole approximation, qualitative explanations are presented for the observed nonlinear behavior. While common behavior in metallic quantum dots or other shapes of metallic nanomaterials was not the significant in our observation.  

scholarly journals Aspect-ratio Dependence of Optical Nonlinearities on Resonance with Longitudinal Surface Plasmon in Au Nanorods: Unique Character versus Common Behavior

2018 ◽  
Vol 1 (1) ◽  
pp. 001-007
Author(s):  
Science Nature
Keyword(s):  
Aspect Ratio ◽  
Surface Plasmon ◽  
Nonlinear Behavior ◽  
Dipole Approximation ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Optical Nonlinearities ◽  
Ratio Dependence ◽  
Unique Character ◽  
Metal Metal

Unique character and common behavior are two distinguished things. In frontier nanoscience and nanotechnology, unique characters were normally obtained in some novel exotics materials such as metal-metal core-shell materials, metallic-semiconducting hybrid nanomaterials, and  organic-inorganics complex nano-compounds. On the other hand, normal behavior of natural phenomena including in nano-size objects were obviously predicted based on their exact size related to confinement effect, and capability to interact with another physical system  in nature.  Here, we report an example of unique character due to evolution nonlinear behavior observed in gold nanorod with their aspect-ratio dependence of optical nonlinearities investigated by femtosecond Z-scan measurements closed to resonance longitudinal surface plasmon peak in gold nanorods (Au NRs). Saturable absorption manifests itself at low excitation (laser irradiances < ~7.0 GW/cm2), while reverse saturable absorption dominates at higher excitation. Both the nonlinear processes are found to increase with the aspect ratio of Au NRs.  Based on the discrete dipole approximation, qualitative explanations are presented for the observed nonlinear behavior. While common behavior in metallic quantum dots or other shapes of metallic nanomaterials was not the significant in our observation.  

scholarly journals Surface Plasmon Resonance Dependent Third-Order Optical Nonlinearities of Silver Nanoplates

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 299
Author(s):  
Marcello Condorelli ◽  
Vittorio Scardaci ◽  
Mario Pulvirenti ◽  
Luisa D’Urso ◽  
Fortunato Neri ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Optical Limiting ◽  
Pulse Generation ◽  
Saturable Absorption ◽  
Nanosecond Laser ◽  
Reverse Saturable Absorption ◽  
Optical Nonlinearities ◽  
Third Order

A systematic study of the surface plasmon resonance (SPR)-dependent nonlinear optical response of Ag nanoplates is presented and discussed. The Ag nanoplates were synthesized using the well-known seed-mediated growth method. By performing the z-scan method with a nanosecond laser (532 nm, 5 ns), the optical nonlinearities of the Ag nanoplates, prepared tuning the SPR contribution in the 400–1000 nm range, were determined. The results showed a SPR-related competition between the saturable absorption and reverse saturable absorption mechanisms, while the nonlinear refraction changed from self-defocusing to self-focusing. Furthermore, the scattering effects contribute to determine the nature of the optical limiting response. The observed SPR-tunable third order optical nonlinearities make Ag nanoplates a suitable candidate to be used in different fields, i.e., laser pulse generation, optical limiting, or bio-imaging applications.

Dynamic saturable optical nonlinearities in free base tetrapyridylporphyrin

2003 ◽  
Vol 07 (06) ◽  
pp. 452-456 ◽  
Author(s):  
Newton M. Barbosa Neto ◽  
Leonardo De Boni ◽  
José J. Rodrigues ◽  
Lino Misoguti ◽  
Cléber R. Mendonça ◽  
...  
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Optical Nonlinearities ◽  
Free Base ◽  
Photophysical Parameters ◽  
Crossing Time ◽  
532 Nm

Dynamic optical nonlinearities in free base tetrapyridylporphyrin ( H 2 TPyP ) solutions were investigated at 532 nm with the Z-scan technique. We observed a reverse saturable absorption process that was found to have a fast contribution related to the singlet population and a slow accumulative contribution arising from the triplet population. The optical excitations and subsequent relaxations can be interpreted with a five-energy-level diagram that allows determination of the excited states photophysical parameters such as triplet and singlet absorption cross-sections and the intersystem crossing time.

scholarly journals Hydrogen-Free Diamond Like Carbon Films with Embedded Cu Nanoparticles: Structure, Composition and Reverse Saturable Absorption Effect

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 760
Author(s):  
Meškinis ◽  
Vasiliauskas ◽  
Viskontas ◽  
Andrulevičius ◽  
Guobienė ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Carbon Films ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Diamond Like Carbon ◽  
Optical Absorbance ◽  
Wide Range ◽  
Absorbance Spectra

In the present research, hydrogen-free diamond like carbon films with embedded copper nanoparticles (DLC:Cu) were grown by simultaneous DC magnetron sputtering of the graphite and copper targets. X-ray photoelectron spectroscopy was used to define the composition of the samples. Atomic force microscopy studies of diamond, like carbon films containing different amount of copper, revealed wide range of the surface morphologies as well as sizes and shapes of the embedded copper nanoclusters. Raman scattering spectra of all the DLC:Cu films investigated were typical for diamond-like carbon (including samples containing more than 60 at.% of copper). sp3/sp2 carbon bond ratio in the films decreased with the increase of the Cu amount in the films. According to the optical absorbance measurements, the surface plasmon resonance related absorption peak of DLC:Cu films was only detected in the films containing 28.45 at.% Cu. For the diamond like carbon films containing more than 40 at.% Cu, a further increase of Cu amount in the nanocomposite resulted in minor changes of the absorbance spectra. Some correlation between the changes of the samples surface morphology as well as phase structure and optical absorbance spectra of the films was found. In all cases, reverse-saturable absorption of the DLC:Cu films was observed. For some DLC:Cu films damage of the sample occurred at higher light fluences that can be related to the heating that is caused by the surface plasmon resonance effect.

scholarly journals Size Dependent Optical Nonlinearity and Optical Limiting Properties of Water Soluble CdSe Quantum Dots

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Anju K. Augustine ◽  
S. Mathew ◽  
P. Radhakrishnan ◽  
V. P. N. Nampoori ◽  
M. Kailasnath
Keyword(s):  
Quantum Dots ◽  
Nonlinear Behavior ◽  
Optical Limiting ◽  
Optical Nonlinearity ◽  
Water Soluble ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
High Laser

We present third-order optical nonlinear absorption in CdSe quantum dots (QDs) with particle sizes in the range of 4.16–5.25 nm which has been evaluated by the Z-scan technique. At an excitation irradiance of 0.54 GW/cm2 the CdSe QDs exhibit reverse saturation indicating a clear nonlinear behavior. Nonlinearity increases with particle size in CdSe QDs within the range of our investigations which in turn depends on the optical band gap. The optical limiting threshold of the QDs varies from 0.35 GW/cm2 to 0.57 GW/cm2 which makes CdSe QDs a promising candidate for reverse-saturable absorption based devices at high laser intensities such as optical limiters.

scholarly journals Numerical Study on the Surface Plasmon Resonance Tunability of Spherical and Non-Spherical Core-Shell Dimer Nanostructures

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1728
Author(s):  
Joshua Fernandes ◽  
Sangmo Kang
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Aspect Ratio ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Shell Thickness ◽  
Numerical Study ◽  
Field Enhancement ◽  
Core Shell

The near-field enhancement and localized surface plasmon resonance (LSPR) on the core-shell noble metal nanostructure surfaces are widely studied for various biomedical applications. However, the study of the optical properties of new plasmonic non-spherical nanostructures is less explored. This numerical study quantifies the optical properties of spherical and non-spherical (prolate and oblate) dimer nanostructures by introducing finite element modelling in COMSOL Multiphysics. The surface plasmon resonance peaks of gold nanostructures should be understood and controlled for use in biological applications such as photothermal therapy and drug delivery. In this study, we find that non-spherical prolate and oblate gold dimers give excellent tunability in a wide range of biological windows. The electromagnetic field enhancement and surface plasmon resonance peak can be tuned by varying the aspect ratio of non-spherical nanostructures, the refractive index of the surrounding medium, shell thickness, and the distance of separation between nanostructures. The absorption spectra exhibit considerably greater dependency on the aspect ratio and refractive index than the shell thickness and separation distance. These results may be essential for applying the spherical and non-spherical nanostructures to various absorption-based applications.

scholarly journals Large Optical Nonlinearity of the Activated Carbon Nanoparticles Prepared by Laser Ablation

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 737
Author(s):  
Yasin Orooji ◽  
Hamed Ghanbari Gol ◽  
Babak Jaleh ◽  
Mohammad Reza Rashidian Vaziri ◽  
Mahtab Eslamipanah
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Laser Ablation ◽  
Carbon Nanoparticles ◽  
Morphological Properties ◽  
Excitation Wavelength ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
High Porosity ◽  
Nlo Properties

Carbon nanoparticles (CNPs) with high porosity and great optical features can be used as a luminescent material. One year later, the same group investigated the NLO properties CNPs and boron-doped CNPs by 532 nm and 1064 nm laser excitations to uncover the underlying physical mechanisms in their NLO response. Hence, a facile approach, laser ablation technique, was employed for carbon nanoparticles (CNPs) synthesis from suspended activated carbon (AC). Morphological properties of the prepared CNPs were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). UV-Vis and fluorescence (FL) spectra were used to optical properties investigation of CNPs. The size distribution of nanoparticles was evaluated using dynamic light scattering (DLS). The nonlinear optical (NLO) coefficients of the synthesized CNPs were determined by the Z-scan method. As a result, strong reverse saturable absorption and self-defocusing effects were observed at the excitation wavelength of 442 nm laser irradiation. These effects were ascribed to the presence of delocalized π-electrons in AC CNPs. To the best of our knowledge, this is the first study investigating the NLO properties of the AC CNPs.

Sign in / Sign up

Export Citation Format

Share Document