Modeling of Er in ceramic YAG and comparison with single-crystal YAG

摘要

Recent advances in the growth of rare earths doped into ceramic (poly-crystalline) materials have generated considerable interest for the next generation of tactical laser systems mainly because ceramics provide larger size, greater strength and lower cost factors in design than their single-crystalline counterparts. For many years, Nd:YAG has been the laser material choice for stability and high power Er has been an ion laser source of interest for defense due to its eye-safe emission at 1.5 μm and has applications in infrared counter-measures, illumination detection, remote sensing and communication technologies. A model Hamiltonian including atomic and crystal-field terms is diagonalized within the complete 4f~(11) SLJM_J basis set which includes 364 states. Within the standard deviation obtained between 117 comparable calculated-to-observed Stark levels, one set of atomic and crystal-field parameters describes the splitting of the Nd~(3+) and Er~(3+) energy levels in either the ceramic or single-crystal host. We report a detailed crystal-field splitting analysis for a number of multiplet manifolds of Nd~(3+) and Er~(3+) in both the ceramic and single-crystal form of YAG (Y_3Al_5O_(12)). With few exceptions, analysis shows that the energy-level structure of Nd~(3+) and Er~(3+) is similar in the ceramic and single-crystal laser rods.