Continuous-wave operation of a broadly tunable thermoelectrically cooled external cavity quantum-cascade laser

Continuous-wave operation of an external cavity quantum-cascade laser on a thermoelectric cooler is reported. The active region of the gain element was based on a bound-to-continuum design emitting near 5.15 mu m. The external cavity setup was arranged in a Littrow configuration. The front facet of the gain chip was antireflection coated. The laser could be tuned over more than 170 cm(-1) from 4.94 to 5.4 mu m and was single mode over more than 140 cm(-1). The output power was in excess of 10 mW over similar to 100 cm(-1) and in excess of 5 mW over similar to 130 cm(-1) at -30 degrees C. (c) 2005 Optical Society of America.