title: Investigation of 2.1-microm lasing properties of Ho:Tm:Cr:YAG crystals under flash-lamp pumping at various operating conditions.
abstract: Flash-lamp-pumped normal-mode and Q-switched 2.1-microm laser operations of Ho:Tm:Cr:YAG crystals have been evaluated under a wide variety of experimental conditions in order to determine an optimum lasing condition and to characterize the laser outputs. Q-switched laser-output energies equal to or in some cases more than the normal-mode laser energies were obtained in the form of a strong single spike by optimizing the opening time of a lithium niobate Q switch. The increase of the normal-mode laser slope efficiency was observed with the increase of the Tm concentration from 2.5 to 4.5 at. % at operating temperatures from 120 K to near room temperature. Laser transitions were observed only at 2.098 and 2.091 microm under various conditions. The 2.091-microm laser transition appeared to be dominant at high-temperature operations with low-reflective-output couplers and to have an energy-level assignment from 5313 cm(-1) to 534 cm(-1) or (and) from 5313 cm(-1) to 536 cm(-1).
authors.forename: K H
authors.initials: KH
authors.lastname: Kim
authors.forename: Y S
authors.initials: YS
authors.lastname: Choi
authors.forename: N P
authors.initials: NP
authors.lastname: Barnes
authors.forename: R V
authors.initials: RV
authors.lastname: Hess
authors.forename: C H
authors.initials: CH
authors.lastname: Bair
authors.forename: P
authors.initials: P
authors.lastname: Brockman