Lasers based on semiconductor materials, so-called diode lasers, are highly efficient, compact light sources. 1 In high volume they can also be produced at very low cost. In contrast to lasers based on specific atomic transitions, such as solid-state or gas lasers, diode laser materials engineering enables generation of light in a large portion of the optical spectrum. 2 The great versatility of diode lasers allows their direct use in many biophotonics applications, including photocoagulation, 3 diffuse optical imaging, 4 and optical coherence tomography (OCT). 5, 6 Nonlinear frequency conversion of diode lasers is an attractive method of overcoming the ...