Stacked quantum cascade laser and detector structure for a monolithic mid-infrared sensing device

We report the stacked quantum cascade laser and detector structures for a monolithic midinfrared sensing device. In the fabricated quantum cascade device, the layer structures for the detector are grown directly on the quantum cascade laser structure. The laser and detector structures thereby are flexibly designed to operate at the same wavelength, without any compensation needed in the way that the active region is designed in the laser and detector. The fabricated monolithic quantum cascade devices exhibit a low threshold current density at the midinfrared wavelength of 5.7 μm. As a result, light emission and detection on the same chip are demonstrated in continuous wave operation at room temperature.We report the stacked quantum cascade laser and detector structures for a monolithic midinfrared sensing device. In the fabricated quantum cascade device, the layer structures for the detector are grown directly on the quantum cascade laser structure. The laser and detector structures thereby are flexibly designed to operate at the same wavelength, without any compensation needed in the way that the active region is designed in the laser and detector. The fabricated monolithic quantum cascade devices exhibit a low threshold current density at the midinfrared wavelength of 5.7 μm. As a result, light emission and detection on the same chip are demonstrated in continuous wave operation at room temperature.