ABSTRACT
We have demonstrated what we believe is the highest slope efficiency reported for a Tm-doped fiber laser operating in the 2-micron spectral region. Using a 1908 nm Tm-doped fiber laser as an in-band pump source, we generated 1.43 W of output power at 2005 nm with 81.25% optical efficiency and 90.2% slope efficiency, with respect to launched pump power. This resonant-pumping approach allowed us to examine the bleaching effects in Tm-doped fiber under resonant pumping. We also analytically show that this pumping method can scale to high power levels while maintaining high efficiency.
ABSTRACT
We have demonstrated what we believe to be the first mid-infrared optical parametric oscillator (OPO) pumped directly by a pulsed Tm-doped fiber laser. The Tm-fiber pump laser produces 30 ns pulses with a repetition rate of 30 kHz at a wavelength of 2 microm. The ZnGeP2 (ZGP) OPO produces 20 ns mid-IR pulses in the 3.4-3.9 microm and 4.1-4.7 microm spectral regions simultaneously. More than 658 mW of mid-IR output power has been generated with a total OPO slope efficiency greater than 35%.
ABSTRACT
We have modeled and demonstrated a scalable, compact, fiber-pumped terahertz source based on difference frequency mixing (DFM) in zinc germanium phosphide (ZGP) capable of producing high average and peak-power pulses. Currently, our terahertz source produces 2 mW of average THz power and >40 W of peak power with sub-nanosecond pulses at a repetition rate of 100 kHz in the range of 2-3 THz without cryogenic cooling or ultra-fast optics. This high average power laser-based terahertz output enables the real-time imaging of concealed objects using an off-the-shelf uncooled microbolometer focal-plane array. With this THz system, we have imaged objects obscured inside in a common shipping envelope, demonstrating the potential of compact laser-based terahertz sources for use in security screening applications.