Abstract

Holmium ions (Ho³⁺) are interesting because of their emission in the eye-safe spectral range slightly above 2 µm due to the ⁵І₇ → ⁵І₈ transition. Tm³⁺,Ho³⁺-codoping is frequently used for excitation of Ho³⁺ ions: Tm³⁺ ions (donors) efficiently absorb pump radiation at ~0.8 µm and non-radiatively transfer their energy to Ho³⁺ ions (acceptors), ³F₄ (Tm³⁺) → ⁵I₇ (Ho³⁺). The codoping scheme also benefits from the combined gain bandwidths of both active ions which is attractive for broadband wavelength tuning and ultrashort pulse generation [1]. Cubic sesquioxides A₂O₃ (where A = Y, Lu, Sc or their mixture) are the well-known host matrices for rare-earth doping. They can be elaborated in the form of transparent polycrystalline ceramics [2]. In the present work, we report on the first Tm,Ho:A₂O₃ ceramic laser.

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