Efficient cross-relaxation laser emitting at λ =2.94 μ

An analysis was made of a new configuration of a laser utilizing the ⁴I_11/2–⁴I_13/2 transition in the Er³⁺ ions in YAG with a high activator concentration (~5×10²¹ cm^–3). It is shown that at a certain excitation rate the cross-relaxation processes increase considerably the lasing efficiency and make it possible to achieve cw emission as a result of transitions from a long-lived lower level.