Continuous-wave, room temperature, low voltage green–blue diode laser

One milestone in the II–VI semiconductor diode lasers was reached recently with the reported demonstration of brief cw laser operation in ZnSe-based quantum well (QW) devices at room temperature, where high reflectivity resonator facet coatings and efforts at efficient heat sinking were employed to reach the conditions necessary for lasing.1 Furthermore, the electrical bias necessary for laser operation was high, especially in terms of the threshold voltage (Vth ~ 10 V). By adapting a particular scheme for improved electrical contacting, in conjunction with an index guided, ridge-waveguide diode laser we show here that continuous wave operation at room temperature can be obtained from these types of devices, without resorting to facet coatings, at voltages of about 4 V.2