25 research outputs found
Dynamics of surface solitons at the edge of chirped optical lattices
We address soliton formation at the edge of chirped optical lattices
imprinted in Kerr-type nonlinear media. We find families of power thresholdless
surface waves that do not exist at other types of lattice interfaces. Such
solitons form due to combined action of internal reflection at the interface,
distributed Bragg-type reflection, and focusing nonlinearity. Remarkably, we
discover that surfaces of chirped lattices are soliton attractors: Below an
energy threshold, solitons launched well within the lattice self-bend toward
the interface, and then stick to it.Comment: 13 pages, 4 figure
Scattering of dipole-mode vector solitons: Theory and experiment
We study, both theoretically and experimentally, the scattering properties of
optical dipole-mode vector solitons - radially asymmetric composite
self-trapped optical beams. First, we analyze the soliton collisions in an
isotropic two-component model with a saturable nonlinearity and demonstrate
that in many cases the scattering dynamics of the dipole-mode solitons allows
us to classify them as ``molecules of light'' - extremely robust spatially
localized objects which survive a wide range of interactions and display many
properties of composite states with a rotational degree of freedom. Next, we
study the composite solitons in an anisotropic nonlinear model that describes
photorefractive nonlinearities, and also present a number of experimental
verifications of our analysis.Comment: 8 pages + 4 pages of figure
Simulation model validation of two common i-line photoresists
In this paper we analyze the dissolution behavior of two common i-line resists (MEGAPOSIT SPR 955-CM and AZ MiR 701) and validate the experimental findings by generating simulation models and implementing them in simulation software. It is demonstrated that with the data provided by a Dissolution Rate Monitor (DRM) the quality of lithography simulation results can improve and can speed up process development and optimization. Different process conditions were investigated to evaluate the area of validity of the simulation model. Lithography simulation software packages LayoutLAB and Dr. LiTHO were used to verify the resist models
Fast and highly accurate simulation of the printing behavior of EUV multilayer defects based on different models
This paper employs rigorous electromagnetic field (EMF)solvers to investigate the printing behavior of EUV multilayer defects. A compression model is applied to compute the defect induced deformation of the multilayer. A fully rigorous Waveguide method is used to simulate the light diffraction from the defective EUV mask. This fully rigorous method is compared with two other methods: A decomposition method combined with the Waveguide algorithm and a hybrid method which computes the multilayer with an analytical method based on the Fresnel-formulas and the mask absorber with a finite-difference time-domain (FDTD) algorithm. Cross sections and the critical dimensions (CD) of the printed wafer features are evaltuated by the application of a threshold model to the computed aerial images. The p rintability of the multilayer defects and their impact on the CD of printed absorber features are investigated versus the defect position, size and other parameters of the defect modell. Finally, the influence of the mask absorber properties on the defect-induced CD variation is investigated. It is shown that the printability of the defect depends on the absorber properties
Simulation of 3D inclined/rotated UV lithography and its application to microneedles
A 3D model is set up to simulate the exposure process of inclined/rotated UV lithography for negative SU-8 resists. The formation of inclined resist pillars and microstructures with truncated cone shapes is simulated based on a 3D exposure model in combination with a post exposure bake model for chemically amplified resists and the Mack development model. As one of the interesting applications employing this promising lithography technique for MEMS fabrication, a solid microneedle for drug delivery is simulated