All Er 3+ doped dielectric 1-D microcavity was fabricated by rf sputtering technique. The microcavity was constituted by half wave Er 3+ doped SiO 2 active layer inserted between two Bragg reflectors consists of ten pairs of SiO 2/ TiO 2 layers also doped with Er 3+ ions. The scanning electron microscopy was used to check the morphology of the structure. Transmission measurements confirm the third and first order cavity resonance at 530 nm and 1560 nm, respectively. The photoluminescence measurements were obtained by optically exciting at the third order cavity resonance using 514.5 nm Ar + laser with an excitation angle of 30°. The Full Width at Half Maximum of the emission peak at 1560 nm decrease with the pump power until the spectral resolution of the detection system of ∼1.0 nm. Moreover, the emission intensity presents a non-linear behavior with the pump power and a threshold at about 24 mW was observed with saturation of the signal at above 185 mW of pump power.

We performed simulations and experiments of wavefront distortions induced by propagating through diode-pumped square-section amplifying laser rods of Nd-doped phosphate glass and 0.5 % N d : 5 % L u : C a F 2 . We observed that depending on the material, wavefront distortions’ profile can vary from a circular lens-like distortion to a complex astigmatic distortion. We showed that this difference comes from the relative sign of piezo-optic tensor coefficients.

No abstract

Thulium-doped calcium fluoride (Tm:CaF2) single-crystalline films are grown on (100)-oriented undoped bulk CaF2 substrates by Liquid Phase Epitaxy (LPE) using LiF as a solvent. Their spectroscopic properties are studied in details. For ~2 at.% Tm-doped films, the active ions are predominantly isolated and are located in oxygen-assisted trigonal sites, C3v(T2). With increasing the Tm doping level, ion clustering is promoted but it is slowed down as compared to bulk crystals. For ~6 at.% Tm-doped films, the majority of active ions form clusters resulting in a "glassy-like" spectroscopic behavior (smooth and broad spectral bands). For such layers, the maximum stimulated-emission cross-section for the 3 F4 → 3 H6 transition is 0.14×10 -20 cm 2 at 1856 nm, the luminescence lifetime of the 3 F4 state is 21.70 ms and the emission bandwidth exceeds 180 nm. The transition probabilities of Tm 3+ ions are determined using the Judd-Ofelt theory. The waveguiding properties of the Tm:CaF2 films are confirmed. Highly-doped Tm:CaF2 epitaxial films are promising for waveguide lasers at ~2 μm.