I n s i t u laser patterned desorption of GaAs quantum wells for monolithic multiple wavelength diode lasers

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Abstract
A new laser‐assisted crystal growth technique that enables three‐dimensional patterning of the GaAs quantum well (QW) active layer within a laser diode structure is demonstrated. In this technique, the GaAs QW is locally heated with superimposed Ar+ and Nd:YAG laser beams during a pause in the metalorganic chemical vapor deposition growth. The evaporation rate of the GaAs is greatly increased by the laser heating, locally thinning the QW. After exposure, the crystal growth is resumed, burying the patterned QW within the crystal. Transmission electron microscopy is used to quantify the lateral profile of the QW thickness while photoluminescence is used to demonstrate the spatial variation of the energy band gap. Finally, multiple wavelength operation of broad‐area diode lasers is observed, consistent with the spatial variation in the energy band gap.