title: High-power continuous-wave mid-infrared radiation generated by difference frequency mixing of diode-laser-seeded fiber amplifiers and its application to dual-beam spectroscopy.
abstract: We report the generation of up to 0.7 mW of narrow-linewidth (<60-MHz) radiation at 3.3 micrometers by difference frequency mixing of a Nd:YAG-seeded 1.6-W Yb fiber amplifier and a 1.5-micrometers diode-laser-seeded 0.6-W Er/Yb fiber amplifier in periodically poled LiNbO3. A conversion efficiency of 0.09%/W (0.47 mWW-2 cm-1) was achieved. A room-air CH4 spectrum acquired with a compact 80-m multipass cell and a dual-beam spectroscopic configuration indicates an absorption sensitivity of +/-2.8 x 10(-5) (+/-1 sigma), corresponding to a sub-parts-in-10(9) (ppb) CH4 sensitivity (0.8 ppb).
authors.affiliation: Rice Quantum Institute, Rice University, Houston, Texas 77005, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Lancaster
authors.forename: D
authors.initials: D
authors.lastname: Richter
authors.forename: R F
authors.initials: RF
authors.lastname: Curl
authors.forename: F K
authors.initials: FK
authors.lastname: Tittel
authors.forename: L
authors.initials: L
authors.lastname: Goldberg
authors.forename: J
authors.initials: J
authors.lastname: Koplow
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D004867:Equipment Design; D005336:Fiber Optic Technology; D007834:Lasers; D008697:Methane / Q000032:analysis*; D009354:Neodymium; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods
chemical_list: D009354:Neodymium; D008697:Methane