In the advancing field of gravitational wave interferometry, the desire for greater sensitivity leads to higher laser powers to reduce shot noise. Current detectors such as LIGO and GEO 600 operate with continuous wave lasers at 10-15 W powers, however future versions will operate at 200 W. One of the major challenges of higher power operation is the creation of thermal lenses in optical components, caused by from the absorption of laser light, yielding optical path deformation and concomitant beam aberrations. This effect is especially problematic in transmissive optical components even at very low levels of absorbed power. In environments that restrict the ability to move optical components (such as gravitational wave detectors), this effect can be used for beneficial purposes, specifically for providing adjustable beam-shaping. The method employs an additional laser having a wavelength strongly absorbed by the substrate and can create an aberration-free parabolic lens can be created provided that the heating beam mode is
substantially larger than the transmitted beam mode. The resulting focal length varies inversely with the heating laser power. This idea forms the basis for an adaptive optical telescope. We present experimental and theoretical results on a laser adaptive mode-matching system that uses an argon laser absorbed in a color glass filter. We characterize the dynamic focal range of the lens and measure the resulting aberrations in the transmitted Nd:YAG beam. Our results are in good agreement with a theoretical model incorporating the temperature distribution of the lens and the relevant thermo-optic parameters.
We define an assembly-layer block language as the Dynamics eXchange Language (DXL), and discuss methods for supporting sequential simulation and distributed simulation by varying the target code generator. DXL is an XML-based language that positions itself between higher level modeling languages and a programming code. Through the use of the XML Document Object Model (DOM), we demonstrate a translation approach that yields a target code in two languages for simulation and distributed computing.
The web has made it easy to create multimedia content, which is
then viewable by the general community at large. By extending
multimedia to include the area of modeling, we make it possible
to share and process model structures in the same way as the
typical web page. For models of the geometric variety, the new
X3D (eXtensible 3D) standard will allow sharing and presentation
of 3D scene graphs within the web browser. We have created a
dynamic model counterpart to X3D, which we call DXL (Dynamics
eXchange Language). DXL is low-level XML-based language, comprising
blocks, ports, and connectors. We will define how DXL is used for
constructing individual level models, as well as multimodels over
multiple abstraction layers.