The extinction ratio of an amplitude modulator is the ratio between the optical power at maximum and minimum transmission. Extinction ratios are dependent on the crystal employed. Conoptics offers three types of crystals for use in the UV, V, NIR and IR. Extinction ratios vary by model and are typically 500:1. In addition, Conoptics offers double-pass configurations allowing for 10,000:1 ER.
In order to optimize the ER ratio, fine adjustments are required in the position of the modulator aligned to the laser beam. Conoptics offers a Model 103 Alignment Tool for initial alignment, while the Model 102 Adjustable Modulator Mount is used for fine adjustment. Completed step-by-step alignment guide is available online in our support section.