Electro-optic RTP (Rubidium Titanyl Phosphate) crystals are mostly used in a temperature-compensated scheme, thus using matched pairs of crystals which offer a range of benefits: Non hygroscopic High electro-optic constant Good extinction ratio No piezo or pyro-electric effects Can be mounted as RTP Q-switch or RTP pulsepicker See below the advantages of using Cristal Laser's index-matched pairs of crystals for those of our customers who perform their own setup.