“…Dual-wavelength lasers are of great interest in wide applications such as terahertz generation, biomedicine, precision measurement and spectroscopy [1][2][3][4]. Based on the transitions between different energy levels or Stark sublevels, direct laser emission with two wavelengths from one laser crystal or two separately pumped laser crystals sharing part or the whole cavity is a conventional method for dual-wavelength generation, the latter of which is much more stable and the power ratio can be tuned by varying the pump power at the expense of a complex cavity and additional pump sources [5][6][7][8][9][10]. For the case of dual-wavelength generation in a single laser crystal, there are strict requirements for cavity mirror coatings [11], and as different wavelengths usually originate from the same upper energy level [12,13], the inherent gain competition causes considerable power fluctuations for each wave.…”