Broadly tunable CW green-to-red laser source based on frequency doubling of a quantum-dot external cavity diode laser in a PPKTP waveguide

In recent years, there has been a growing interest in the development of broadly tunable compact coherent sources emitting in the visible spectral region at around 550 nm - 650 nm, which are of interest for a wide range of applications, such as photodynamic therapy, biophotonic applications and laser projection displays. An attractive approach for the implementation of such laser sources is frequency doubling of infrared light, particularly into the orange spectral region, for which compact and efficient sources are relatively scarce [1]. In this respect, quantum dot materials have shown a great promise for development of a new generation of optoelectronics devices, due to the temperature insensibility and the broad gain bandwidth. The wide tunability offered by the quantum-dot external cavity diode laser (QD-ECDL) [2] is very promising for the development of a tunable green-yellow-orange-red source based on a single laser device and a single waveguide.