RESUMO
Taking advantage of light-emitting-diode (LED) performance breakthrough driven by the lighting market, we report, to the best of our knowledge, the first LED-pumped chromium-doped crystal laser oscillator and amplifier based on alexandrite crystals (Cr3+:BeAl2O4). We developed a Ce:YAG concentrator as the pumped source, illuminated by blue LEDs that can be easily power scaled. With 2200 LEDs (450 nm), the Ce:YAG concentrator can deliver to the gain medium up to 268 mJ at 10 Hz at 550 nm with a irradiance of 8.5 kW/cm2. We demonstrate, in oscillator configuration, an LED-pumped alexandrite laser delivering an energy of 2.9 mJ at 748 nm in free running operation. In the cavity, we measured a double-pass small signal gain of 1.28, which is in good agreement with numerical simulations. As an amplifier, the system demonstrated to boost a CW Ti:sapphire laser by a factor of 4 at 750 nm in eight passes with a large tuning range from 710 nm to 800 nm.
RESUMO
We describe here what is, to the best of our knowledge, the first LED pumped Nd:YVO4 laser. Near-IR LED arrays with a wavelength centered close to 850 nm were used to pump transversely the crystal. By pulsing LEDs, with a duration of the order of the laser transition lifetime, we obtained sufficient pump intensities to reach the laser threshold. At a frequency of 250 Hz, we obtained an output energy of 40 µJ at 1064 nm for an input pump energy of 7.4 mJ, which corresponds to an optical efficiency of 0.5%. Experimental results of small signal gain are compared with theoretical analysis.
