Table 1.

The energy E (cm⁻¹) of optical transitions between the ground ⁷F₆ and excited ⁵D₄ multiplets of the Tb³⁺ ion observed in the absorption and PL spectra of the KTF crystal at T = 90 K.

Absorption		Luminescence
Transition Label	E	Transition Label	E
1	20,726	3′	20,646
2	20,704	4′	20,624
3	20,646	5′	20,602
4	20,624	6′	20,560
5	20,602	7′	20,564
6	20,560	8′	20,513
7	20,564	9′	20,478
8	20,513	10′	20,409
9	20,473	11′	20,393
		12′	20,371
		13′	20,350
		14′	20,323
		15′	20,307