title: 4.8 μm difference-frequency generation using a waveguide-PPLN crystal and its application to mid-infrared Lamb-dip spectroscopy.
abstract: Difference-frequency generation of 4.8 μm mid-infrared light was performed using a waveguide periodically poled LiNbO₃ (PPLN) crystal. 871 and 1064 nm external-cavity diode lasers followed by tapered amplifiers were used as pump sources. A conversion efficiency of ~2%/W with the output power of 2 mW was achieved even under considerable absorption of the crystal at this wavelength. Lamb-dip spectroscopy of carbonyl sulfide was demonstrated showing the satisfactory performance of this device for saturation spectroscopy. The observed dip width shows that the laser linewidth is ~2 MHz, which corresponds to those of the pump lasers.
authors.affiliation: Research Core for Extreme Quantum World, Okayama University, Okayama, Japan. susumukuma@fphy.hep.okayama‑u.ac.jp
authors.forename: Susumu
authors.initials: S
authors.lastname: Kuma
authors.forename: Yuki
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Kousuke
authors.initials: K
authors.lastname: Tsutsumi
authors.forename: Noboru
authors.initials: N
authors.lastname: Sasao
authors.forename: Satoshi
authors.initials: S
authors.lastname: Uetake