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We replace the air around tapered silica fibres or within hollow-core photonic crystal fibres with silica aerogel. This retains the important device characteristics, including gas permeability, but adds protection and enables new devices.
The 23 full-factorial Central Composite Design (CCD) and response surface methodology (RSM) was applied to explain the effect and interaction of three factors in the process of Fe3O4/SiO2 nanoparticle: NaOH dosage, Fe3O4/SiO2 ratio and Fe2+/Fe3+ ratio. For the CCD optimization purposes, the canonical parameters was employed where the predicted average size of the nanoparticles was 115.39 nm, and the...
Silica aerogel is a very light and highly porous form of silica glass, with densities and refractive indices much lower than those of ordinary solids. We describe optical interactions with aerogel surrounding tapered fibres or inside the holes of photonic crystal fibres. This enables a new class of fibre devices exploiting the properties of the aerogel as a rigid yet porous replacement for air, as...
We demonstrate spectral broadening in tapered optical fibres embedded in silica aerogel. The aerogel provides protection to the taper without noticeably affecting the refractive and dispersive properties or power handling.
Arrays of microsensors may be employed for accurate detection of multiple gases possibly existing simultaneously in an environment. They can be made reconfigurable for improving efficiency and reliability. Constituent microsensors in such a reconfigurable array are highly desirable to operate in an ultra low power regime, have a short response time, and take as small chip area as possible. Metal oxide...
We have developed the new production methods of silica aerogel with the refractive indices between 1.15 and 1.25. Since the velocity of the photoelectric electron from the 511keV photon is 0.866c and the maximum velocity of the Compton electron is 0.8c, only photoelectric electrons occurs the Cherenkov light inside the radiator with n ~ 1.2. We are constructing the simple prototype PET detectors using...
We use controlled hole collapse in photonic crystal fibres to reduce the splice loss between dissimilar fibres. We also describe a hollow-core PCF as a support for a waveguide core made from silica aerogel.
We filled the core of hollow-core photonic crystal fibre with silica aerogel. The filled fibre exhibits a shifted bandgap and a region of broadband guidance in good agreement with simulation.
Silica aerogel-fiber composites were prepared via a heat pressing process. Nonwoven fibers were distributed inside the silica aerogels as a composite to act as a supporting skeleton which increased the mechanical strength. The morphology, pore structure, benzene adsorption capacities of the silica aerogels and the composites were characterized. The results show that the silica aerogel-fiber composites...
This paper reviews the processes developed at General Atomics (GA) in the past several years to fabricate a variety of spherical foam targets at various densities for the inertial confinement fusion (ICF) community. The two most common chemical systems used to produce spherical foam targets have been resorcinol-formaldehyde (R/F) aerogel and divinylbenzene (DVB). Spherical targets have been made in...
In this paper, nano-porous silica aerogels were prepared via sol-gel process with acid/base two-step catalysis technique. Silica aerogel structure can be effectively controlled by changing experimental parameter. Ultralow density silica aerogel with density as low as 3.4 mg/cm3 has been successfully prepared. Transmission electron microscope (TEM), gas chromatography/mass spectrometry (GC/MS) and...
Two step acid-base catalyzed silica xerogels which had integrated structure were prepared through sol-gel and ambient pressure drying. Silica xerogels powder, TiO2 powder and short fibers were added as the additives in order to improve the properties of silica xerogels. The porous structure was estimated by the means of nitrogen adsorption method and mercury intrusion porosimetry (MIP). According...
Summary form only given. The Sandia Z dynamic hohlraum radiation drive produces high radiation powers and energies. Using these high powers and energies, a new in-situ diagnostic has been developed and tested, that uses the super-sonic to sub-sonic transition of a Marshak radiation wave in a cylindrical block of SiO2 aerogel foam. When this transition takes place, a shock is launched, with a velocity...
Summary form only given. We have measured the production of 10 keV X-rays from low-density Ge-doped aerogel targets at the OMEGA laser. The targets were 1.2 mm long by 1.5 mm diameter beryllium cylinders filled with Ge-doped (20 atomic percent) SiO2 foam. The doped-foam density was 5 or 7 mg/cc. These targets are a major advance over previous doped aerogels: instead of suspending the dopant in the...
Summary form only given. A method has been developed to launch macroscopic flyer plates using the intense magnetic pressure produced by the Sandia Z accelerator. The accelerator is capable of producing >20 MA current pulses with ~200 ns rise-time into a short circuit load, generating intense magnetic fields within the anode cathode (AK) gap. The resulting Lorentz force enables the Z accelerator...
New production methods of silica aerogel with high and low refractive indices have been developed. A very slow shrinkage of alcogel at room temperature has made possible producing aerogel with high refractive indices of up to 1.265 without cracks. Even higher refractive indices than 1.08, the transmission length of the aerogel obtained from this technique has been measured to be about 10 to 20 mm...
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