This paper reviews the recent development of inorganic and hybrid nanomaterials for optical limiting applications. The synthesis, testing method, optical limiting property and mechanism of several representative classes of nanomaterial, including carbon nanotubes, silver and gold nanocomposites, and selected other conducting and semiconducting nanomaterials, are introduced separately. The nonlinear optical mechanisms observed in inorganic nanomaterials, i.e. nonlinear scattering, two-photon absorption, free-carrier absorption, etc, are discussed in conjunction with the influence of the material properties and the laser source on the optical limiting performance.

https://iopscience.iop.org/article/10.1088/1464-4258/11/2/024001/pdf

Inorganic and hybrid nanostructures for optical limiting

Raman spectroscopy has enabled researchers to map the specific chemical makeup of surfaces, solutions, and even cells. However, the inherent insensitivity of the technique makes it difficult to use and statistically complicated. When Raman active molecules are near gold or silver nanoparticles, the Raman intensity is significantly amplified. This phenomenon is referred to as surface-enhanced Raman spectroscopy (SERS). The extent of SERS enhancement is due to a variety of factors such as nanoparticle size, shape, material, and configuration. The choice of Raman reporters and protective coatings will also influence SERS enhancement. This review provides an introduction to how these factors influence signal enhancement and how to optimize them during synthesis of SERS nanoparticles.

/pdf/nanoparticle-properties-and-synthesis-effects-on-surface-3vzwcqif59.pdf

Nanoparticle Properties and Synthesis Effects on Surface-Enhanced Raman Scattering Enhancement Factor: An Introduction

A radiation attenuation system for use with Computed Tomography procedures is disclosed. The system includes a shield made of a radiation attenuation material and may be useful in blocking or attenuating radiation, and assisting in the protection of at least one of a patient and a medical personnel present during the Computed Tomography procedure. The system may be useful for both Computed Tomography scanning procedures and Computed Tomography fluoroscopy procedures.

Radiation attenuation system

A microfluidic substrate assembly (10) includes a substrate body (12) having at least one fluid inlet port (14). At least one microscale fluid flow channel (16) in the substrate is in fluid communication with the inlet port for transport of a fluid to be tested. The substrate body also has a plurality of sockets (20), with each of one or more sockets configures to receive an operative component (21). At least one socket is in communication with the microscale fluid flow channel.

Configurable microfluidic substrate assembly

Spacecraft with electrostatic dissipative surfaces are disclosed herein. The surface has layer which includes a plurality of carbon nanotubes to incorporate electrical conductivity into space durable polymeric layers without degrading optical transparency, solar absorptivity or mechanical properties.

Esd coatings for use with spacecraft

Novel appliques (10) comprising oxyhalopolymer-adhesive composites wherein the adhesive layer (14) of the composite is chemically bonded to reactive sites on at least one side of the oxyhalopolymer layer (12), possess superior peel strengths, resistance to delamination and protective properties, including protection of surfaces from lightning strike to seamless protective liners for tanks. The appliques are suitable for printing architectural designs thereon. Multilayer specialty appliques can be fabricated from the above fundamental oxyhalopolymer-adhesive composite structure, including layered adhesives for encapsulating tridimensional mechanical and electrical devices, such as RF, or microwave sensitive antennae for transmitting and receiving communications, providing protection from environmental electromagnetic effects, shock and impact resistance, multidimensional deformable structures; housing for temperature control systems, etc. The properties of the appliques can be modified by introducing various additives to the halopolymer and/or adhesive layers to customize electrical, and optical shielding, or reflectivity, corrosion resistance, and the like.

Oxyhalopolymer protective multifunctional appliques and paint replacement films

The interband transition contributions to the optical properties of silver nanoparticles in fluoropolymer matrices are investigated. For the materials in this study, nanoparticle synthesis within the existing polymer matrix is accomplished using an infusion process that consists of diffusing an organometallic precursor gas into the free volume of the fluoropolymer and decomposing the precursor followed by metal nanoparticle nucleation and growth. The resulting polymer matrix nanocomposite has optical properties that are dominated by the response of the nanoparticles owing to the broadbanded transparency of the fluoropolymer matrix. The optical properties of these composites are compared to Maxwell-Garnett and Mie theory with results indicating that interband transitions excited in the silver nanoparticles affect the optical absorption over a range of frequencies including the surface plasmon resonance. It is shown that calculations of the optical absorption spectrum using published data for the silver dielectric function do not accurately describe the measured material response and that a classical model for bound and free electron behavior can best be used to represent the dielectric function of silver.

Terrence G. Vargo

Papers

Oxyhalopolymer protective multifunctional appliques and paint replacement films

Modeling interband transitions in silver nanoparticle-fluoropolymer composites.

Linear and nonlinear optical behavior of palladium nanoparticle reinforced fluoropolymer composites