8B7 - Energy transfer and CW laser action in Ho3+:Er2O3

Er
2
O
3
: Ho
³⁺
is an unusual laser material in that the host crystal itself provides the dominant pumping mechanism by means of energy transfer. The additional pumping bands due to Er
³⁺
and the consequent efficient transfer of energy to the Ho
³⁺
laser ion lead to relatively low threshold laser operation: 5 joules pulsed and 200W CW for a 12mm long crystal at 77°K. The emission waveleng this 2.121μ, a region of good atmospheric transmission. Additional laser experiments were carried out at 145°K. Excitation and fluorescence spectra are discussed.