Type: Zeitschriftenaufsatz (reviewed)
The output power and efficiency of linearly polarized high power Nd:YAG lasers is limited by depolarization and bifocusing. Both effects degrade the beam quality and decrease the output power. In a single pass configuration, - and -cut crystals can be used to reduce the depolarization. Here, we compare -, - and -cut crystals in an oscillator configuration. As expected it was possible to reduce the depolarization loss by using -cut crystals in our configuration, while the depolarization loss was higher for -cut crystals. The thermal lens establishing in these crystals is not circular, which can degrade beam quality in high power operation.