Numerical analysis of the 3D nonlinear inter-action of the optical fields in a cavity with thermal effects, such as the temperature- dependent refractive index distribution, absorbed pump power distribution, doping distribution, population inversion etc. is of growing importance to optimize SSL sytems Intuitive approach based on personal experience is still important, but is not sufficient due to the tendency to minia-turize laser systems and simultaneously to increase their power output, causing interaction of strong fields in very small volumes.
To model the complex interactions in a laser cavity, LASCAD software combines the necessary simulation tools into one package.
Based on a quantitave understanding of the multiphysics effects in laser cavities, LASCAD allows the laser engineer to optimize important features of a laser like beam quality and laser power output.
LASCAD offers:
·Thermal and Structural Finite Element Analysis (FEA)
·ABCD Gaussian Beam Propagation
·Physical Optics Beam Propagation (BPM)
·Computation of Laser Power Output and Beam Quality
·Dynamic Analysis of Multimode and Q-Switch Operation (DMA)
Design of LASCADä has been guided by three basic ideas:
• The Optical Workbench on the PC
• The Laser Engineering Tool
• The Educational Tool
LASCAD - The Optical Workbench on the PC
An easy-to-use and clearly organized user interface permits intuitive modeling and design of laser cavities. It helps the engi- neer understand experimental results without wasting valuable time studying complicated manuals:
•Optical elements like mirrors, lenses and crystals can be added, combined, positioned, adjusted or removed with a mouse click.
•Astigmatism of resonator and crystal is automatically analyzed.
•Finite Element Analysis, ABCD, DMA and Physical Optics Code can easily be started from a menu bar.
LASCAD - The Laser Engineering Tool
Finite Element Analysis (FEA)
FEA is used to compute temperature distri-bution, deformation, and stress or fracture mechanics in laser crystals, or to analyze the effect of different cooling systems.
The FEA code of LASCAD has been specifi-cally developed to meet the demands of laser simulation. Automatic mesh generation facili-tates use of FEA for engineers not being familiar with this method.
Pre-designed FEA models with adjustable parameters, such as dimensions of crystal or material properties, are provided to assist the engineer with different configurations.
2D and 3D graphical tools are available to visualize pump light distribution, boundary conditions, and results of FEA.
Configurations available with LASCAD:
•End pumped rods and slabs with the pump light distribution being modeled by the use of supergaussian functions or pumping from both ends.
•Rods and slabs, with top hat pump profile along crystal axis and supergaussian distribution perpendicular to the axis.
Configurations available with LASCAD:
Side pumped rods with several diode arrays being grouped around and along the rod. Symmetrical, as well as unsymmet-rical arrangements are possible.
Side pumped slabs with tilted end faces.
Rods and slabs with numerical input of pump light distribution generated by the ray tracing codes ZEMAX or TracePro
Composite crystals can be used with all models. For instance, rods with undoped end caps, and sandwiched slabs with doped and undoped layers, can be modeled.
Heat sinks can also be included into the FEA model. For example, temperature distribution and deformation in a structure consisting of crystal slab between to copper plates can be computed.
In the following, several pictures visualizing FEA results are shown.
Example: Heat load distribution in a rod with undoped end-caps.
Example: Temperature distribution in arod with undoped end-caps
Example: z-component of displacement in a rod with undoped end-caps
Side Pumped Rod
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