Cross-relaxation Energy Transfer Research Articles

Emission properties, oscillator strengths and laser parameters of Er 3+ in LiYF 4 at 2.7 μm

We reported already on the first observation of laser emission at several wavelengths (2.7–2.85 μm) for transitions between the 4I 11 2 and 4I 13 2 states of Er 3+ in LiYF 4 at room temperature under 0.8 μm diode laser and 0.514 μm argon laser excitation. In order to stabilise the action of CW lasing at 2.66 and 2.77 μm, the effect of polarisation on 4I 11 2 a ̊ 4I 13 2 emission is studied, and oscillator strengths from ground state and excited states are calculated to predict a useful cross relaxation energy transfer.

Energy transfer in CaWO4: Sm3+

The interaction between Sm3+ ions in CaWO4 crystals has been investigated using high resolution dye laser spectroscopy techniques. The results are found to be different from those obtained using either broadband or intermediate resolution laser excitation sources. At low temperatures, both concentration quenching through cross-relaxation and resonant energy transfer processes are found to take place by exchange interaction. At high temperatures, energy transfer between Sm3+ ions in nonequivalent crystal field sites takes place by a two-phonon diffusion process with a diffusion coefficient of the order of 4.9×10−10 cm2 s−1.