Dual tunable wavelength Er,Yb:glass laser for terahertz beat frequency generation

Dual tunable wavelength operation of Er,Yb:phosphate glass laser is reported. The spatial separation of the laser eigenstates and the use of two properly designed intracavity etalons permit one to tune the two wavelengths independently from 1540.5 to 1562.7 nm. The generated beat note, monitored using a Michelson interferometer, is experimentally shown to be adjustable from dc to 2.7 THz. The linewidth of this beat note is found to be less than 10 kHz. Several applications are discussed.