A narrow-linewidth external cavity quantum dot laser for high-resolution   spectroscopy in the near-infrared and yellow spectral ranges
  We demonstrate a diode laser system which is suitable for high-resolution spectroscopy in the 1200 nm and yellow spectral ranges. It is based on a two-facet quantum dot chip in a Littrow-type external cavity configuration. The laser is tunable in the range 1125 -1280 nm, with an output power of more than 200 mW and exhibits a free-running linewidth of 200 kHz. Amplitude and frequency noise were characterized, including the dependence of frequency noise on the cavity length. Frequency stabilization to a high-finesse reference cavity is demonstrated reducing the linewidth to about 20 - 30 kHz. Yellow light (> 3 mW) at 578 nm was generated by frequency doubling in an enhancement cavity containing a PPLN crystal. The source has potential application for precision spectroscopy of ultra-cold Yb atoms and molecular hydrogen ions. 
A. Yu. Nevsky, U. Bressel, Ch. Eisele, M. Okhapkin, S. Schiller   (Heinrich-Heine University of Duesseldorf, Germany) A. Gub...