The QF4050D3 from Thorlabs is a single spatial mode, 4050 nm Fabry-Perot Quantum Cascade Laser that provides an output power of up to 1.2 watts. This laser operates in continuous wave (CW) mode at room temperature. The QF4050D3 is mounted on an open heatsink D-mount package with both the cathode and anode isolated from the heatsink base. This discrete semiconductor laser is a compact light source suited to many applications. A thermistor is integrated for temperature monitoring. There is no monitor photodiode.