#semiconductor #news Bifunctional quantum cascade laser/detector - Semiconductor Today

#semiconductor #news Bifunctional quantum cascade laser/detector - Semiconductor Today

Bifunctional quantum cascade laser/detector Vienna University of Technology has developed a quantum cascade device that can act as both laser and detector over the same wavelength range [Benedikt Schwarz et al, Appl. Phys. Lett., vol101, p191109, 2012]. Quantum cascade (QC) structures consist of a large number of semiconductor layers that present a series of steps as electrons proceed through the device. Transitions between the energy levels of the steps can be arranged to emit coherent photons, if the laser condition of population inversion can be produced through a lower level that is very rapidly emptied. The first QC laser (QCL) was reported in 1994. More recently, QC structures have been produced that reverse the process by detecting electromagnetic radiation. Figure 1: Optical output power and current-voltage characteristic of the bifunctional device. Curves were mea...

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