Whats the easiest way to get the beam through the modulators? What polarization and beam size?
To align the modulator, we suggest using the Model 9071 four-axis tilt aligner. In order to minimize clipping through the modulator, a good rule of thumb is that the beam diameter should be less than one-third the aperture size. For example, a modulator with a 2-mm aperture can accommodate a 0.7-mm-diameter beam. Larger beams can be focused into the modulator and then collimated afterwards using a pair of lenses. If you do this, make sure the intensity inside the modulator doesn’t exceed the damage threshold. For the phase modulators, the laser beam should be well collimated and its polarization should be oriented vertically to within 1°. For our amplitude modulators, the beam can be either vertically or horizontally polarized. For an unpolarized laser, the polarizer should have an extinction ratio greater than 100:1. We recommend our Model 552X Glan-Thompson polarizers or our low-cost Model 5511 sheet polarizers.
