High power broadband orange laser by double-pass sum-frequency mixing in MgO:PPLN

A Watt-level broadband orange laser is demonstrated by use of double-pass sum frequency mixing in a step-chirped MgO-doped periodically poled lithium niobate (MgO:PPLN) crystal (Λ = 10.1–10.4 µm). The temperature-gradient technique is used to enhance the bandwidth of the output spectrum. The maximum output of the orange laser in the 600 nm spectral region is up to 1.1 W whereas the maximum bandwidth of ~7.2 nm was accomplished employing a 40 mm long MgO:PPLN structure. This scheme presents an attractive approach for the generation of high power and broadband short-wavelength lasers from a single crystal, which may extend the potential biomedical and spectroscopic applications.