Large-aperture plasma-assisted deposition of inertial confinement fusion laser coatings

Abstract

Plasma-assisted electron-beam evaporation leads to changes in the crystallinity, density, and stresses of thin films. A dual-source plasma system provides stress control of large-aperture, high-fluence coatings used in vacuum for substrates 1m in aperture.

TiO 2 films prepared using plasma ion assisted deposition for photocatalytic application

“…The calculated results of crystal sizes estimated from Scherrer's formula based on anatase (1 0 1) peak are listed in Table 2, showing that the average crystallite size increases with the plasma current density. The measured temperature rise during the deposition was $50 C, indicating the enhancement in crystallinity is primarily due to the enhanced ad-atoms movements in the PIAD process, but not from thermal effects [8].…”

“…Peak intensity increases slightly with the increasing plasma current density. The peaks of the PIAD TiO 2 films show a reduction in the full width at half maximum (FWHM) of the Bragg angles with increasing plasma current density, indicating an increase in the crystal sizes [8]. The calculated results of crystal sizes estimated from Scherrer's formula based on anatase (1 0 1) peak are listed in Table 2, showing that the average crystallite size increases with the plasma current density.…”

“…Anatase TiO 2 structures may be obtained without the need of high temperature processing using a plasma ion assisted deposition (PIAD) [8]. This is possible due to the energy of the deposited adatoms with ion assistance increasing the probability of lattice relaxation and transitions from a metastable state to a stable state [9,10].…”

Development of Mirror Coatings for Gravitational Wave Detectors

“…Experiments have also suggested that oxygen deficiency in tantala coatings can increase the associated mechanical loss. The use of ion-assist (or plasma-assist) is well documented for controlling the stress, stability, stoichiometry, and density of both IBD and non-IBD films [56] and currently plays an important role in high performance optical applications, such as those requiring a high laser-damage threshold (LDT) [57]. In relation to mechanical loss, the use of ion assistance is observed to affect the level of mechanical loss in mirror coatings, however, this has not been used to reduce the mechanical loss below single-ion beam deposition [54,58].…”

The ablation of Ta2O5 film by pulsed nanosecond Gaussian laser beams

“…Laser induced thin film damage is not only closely related to coating material and the process, conditions, methods of coating, but also to the laser parameters [10,11]. Ta 2 O 5 films possess wide spectral transmission window as well as high refractive index [12].…”