Improved Ti:sapphire laser performance with new high figure of merit crystals

Theory of nonradiative decay dynamics in intensely pumped solid-state laser media via laser photothermal diagnostics

“…Figure 5 shows the gradual transition from one-to three-dimensional configuration. For pump-beam waists Rу10 3 m one-dimensional behavior is observed, whereas the Rр10 2 m curves peak earlier, a clear indication that tight focusing interferes with the measurement of the relaxation time constant 21 : The calculations show that it is necessary to know accurately the beam waist R for precise measurements of metastable state relaxation time constants, when R 2 /␣ϳ200 21 . In the situation shown in Fig.…”

“…High pump rates of the excited state result in earlier saturation ͑flattening͒ of the thermal flux per unit depth released in the bulk of the laser medium, due to the high transition rate out of the ground state and attainment of the maximum dynamic steady-state population inversion of the metastable laser level ͉2͘. Once saturation ͑i.e., dynamic steady state͒ has been attained and the optical pump is switched off, nonradiative decay controlled by the lifetime 21 takes place, irrespective of the rate at which the dynamic steady state was attained, Fig. 2.…”

“…͑18͒. Therefore, it has been found to be more convenient to monitor the luminescence transient experimentally and deduce from the rise and decay times the time constants 21 and . 23 This combined luminescencephotothermal approach offers the advantage of a simple integrated experimental setup with the superior SNR of the luminescence transient, the results of which can be used as input data to the photothermal signal modeling.…”

“…In the special case of unsaturated laser media with ''instantaneous'' deexcitation time constant 21 ͑i.e., when 21 Ӎ0 on the time scale of the earliest observation time t͒, the source term F(t 0 ), Eq. ͑34b͒, can be written…”

Laser Cooling With Ultrafast Pulse Trains

“…only one pulse in the laser cavity at a time, requiring a cavity round-trip length of 20 cm and a very compact laser. The long (1 cm) Ti:S crystal was hydrogen-annealed to minimize infrared reabsorption, which often limits the power of Ti:S lasers [8]. The Gires-Tournois interferometer mirror provided large negative dispersion at 871 nm to cancel the material dispersion of the long crystal and allow ultrashort pulse formation.…”