Dual-wavelength resonant pumping of compact Er:YAG lasers providing high power output at 1645.55 nm for methane detection

摘要

Eye safe laser operation of resonantly pumped Er:YAG laser systems is demonstrated in cw and Q-switched operation. Using narrow bandwidth diode laser modules we realized a single pump configuration providing an optical efficiency of about 30% which leads to an output power of 2.5 in cw mode and 6.6 mJ in Q-switched operation with a pulse width of 60 ns at pulse repetition frequencies of up to 125 Hz. By implementing an intra-cavity etalon we were able tune the laser wavelength while achieving a spectral width of 0.35 pm and a long-term frequency fluctuation of about 40 MHz. In dual-side pumping configuration we obtained dual-wavelength pumping with 1532 nm and 1455 nm diode lasers which leads to 1.1 W output power. Compared to single wavelength pumping, the efficiency of the laser system was doubled. The feasibility of methane detection was demonstrated In cw and pulsed mode.