Laser excited fluorescence and selfhyphen;absorption in LaF3:Nd3+

摘要

Fluorescence of LaF3:Nd3+has been observed at 77thinsp;deg;K and at room temperature in the region 5170ndash;9020 Aring; using the Ar+, 5145 Aring; laser excitation. The fluorescence at 77thinsp;deg;K consists of lines orginating in theE,D, andRlevels of Nd3+as well as in theKandLlevels which are probably reached as a result of a two photon excitation of Nd3+. TheSandAlevels are also found to fluoresce at room temperature, and it is suggested that thermally assisted ion pair processes may be responsible for the population buildup in these levels at high temperatures. Transitions from theR(4F3/2) levels to the ground stateZ1and first excited stateZ2(45 cmminus;1) showed selfhyphen;reversal at 77thinsp;deg;K. Owing to the simple geometry of laser excitation, the degree of selfhyphen;reversal could be directly related to the oscillator strength of the transitions. This enabled an evaluation of the totalfnumber of theZndash;Rtransitions which could be compared with an earlier value obtained from direct absorption measurements.