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Laser setup
The laser source of the LASER4DIY project is a diode pumped solid state laser with a Neodymium-doped yttrium orthovanadate (Nd:YVO4) crystal. This widely-used laser is especially suitable for this usecase, since the Nd:YVO4 cristal is cheap, easy to obtain and also, based on the use of the so called bounce geometry, very efficient. In figure 1 you can see the setup of the laser system, which is very similar to the puplication by Thomas and Damzen, 2011 [1]
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Because the pump light is only exciting a part of the Nd:YVO crystal and therefore a temparture gradient is formed, a thermal lense occurs. Dependend on how big the temperature gradient is, a different refractory index occurs, which let the emitted radation leave the crystal under a different angle. To tune the laser beam to maximum power than the lengths L1 and L2 (see figure 1) has to be adjusted to this angle.
Simulation
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of the laser source
Simulation was done using the program LASCAD. A finite element analysis (FEA) for the thermal effects of the Nd:YVO4 crystal is possible with it, allowing to determine the exact geometry of the resonator. Especially the distances of mirror 1 and the uncoupling mirror to the crystal (see diagram 1) are important for the construction later on. Additionally the simulation program can calculate the average power in CW mode (continuous wave mode), as well as the peak power of the laser source when using the Q switch. The simulation was done without frequency doubler, as it is less important for the laser geometry.
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