Galvo drive

The Brewster plate can be tilted in a controllable way by a galvo-drive [5.94], where the tilting angle is determined by the strength of the magnetic field. In order to avoid a translational shift of the laser beam when tilting the plate, two plates with a = a can be used (Fig. 5.57b), which are tilted into opposite directions. This gives twice the shift of (5.91). 

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