Pulsed-laser deposition (PLD) is a versatile technique for thin film deposition. The generation and propagation of laser-induced
plasmas have been extensively studied. Other plasma sources have been combined with PLD to improve the film
qualities. The knowledge about the interactions between the laser-induced plasmas and additional plasmas and their
effects on film growth is still limited. We have investigated the optical emission spectra from the interaction region of
low-pressure ECR microwave plasmas and pulsed-laser-induced plasmas. In this region, the spatial and temporal
distributions of the laser-ablated species were altered while very few collisions were expected in the ambient gas due to
the low pressure. The results were compared with those with laser ablation or ECR microwave discharge along. The
mechanisms and effects of the interactions were discussed.
Currently, enhancement of Raman scattering for nanoscale characterization is mostly based on tip- or surface-enhanced
methods. However, both approaches have some dilemmas which impede their wide applications. In this study, we
investigated a novel approach to enhance Raman scattering using closely-packed micro and submicro silica spherical
particles. The enhancement phenomena haven been demonstrated by the silicon phonon mode of crystalline silicon (c-Si)
substrates as well as the vibration modes of single-walled carbon nanotubes (SWCNTs) covered with microparticles. The
studies show that the enhancement effects strongly depend on the particle size. Specifically, when the particle size is
close to the beam waist of the incident laser, the strongest enhancement occurs. Numerical simulations are performed to
calculate electric field distribution inside and outside the dielectric particles using the OptiwaveTM software which is
based on the finite difference time domain (FDTD) algorithm under the perfectly matched layer (PML) boundary
conditions. The simulated results reveal the existence of photonic nanojects in the vicinity outside the particles along
with the light traveling direction. The nanojets outside of the particles with a length of 100 nm and a waist of 120 nm are
believed to be the base for Raman scattering enhancement. This technique has potential applications in many areas such
as surface science, biology, and microelectronics.
Three-dimensional (3-D) photonic crystals were fabricated by laser-assisted imprinting of self-assembled silica particles into silicon substrates. The multilayer self-assembly of silica particles were formed on the silicon substrates using isothermal heating evaporation approach. A KrF excimer laser pulse with a wavelength of 248 nm and a duration of 23 ns was used to melt the silicon substrate surface, which infiltrated and solidified over the assembled silica particles. By removing the silica particles embedded in the silicon using hydrofluoric (HF) acid, inverse-opal photonic crystals were fabricated This technique is capable of fabricating structures with complete photonic bandgaps (PBG), and engineering the photonic bandgaps by flexibly varying the silica particle size.