High-responsivity operation of quantum cascade detectors at 9 µm.

Quantum cascade detectors (QCDs) are devices operating at zero external bias with a low dark-current. They show linear detection and high saturation intensities, making them suitable candidates for heterodyne detection in long-wave infrared (LWIR) free space optical communication systems. We present an approach to mitigate the performance limitation at long wavelengths, by a comparison of similar single and multi-period QCDs for optimizing their responsivity and noise behaviour.

Revisiting the Fabry-Perot reflectivity method for mid-infrared optical index measurement: case study of InGaAs, AlInAs, and InP.

We revisit the Fabry-Perot (FP) reflectivity method to measure optical indices in the mid-infrared spectrum. This simple approach can be readily implemented using a standard Fourier transform infrared spectrometer. Measuring samples with multiple heights allows for enhanced precision of the measurement, making the FP method consistent in values and uncertainties with more advanced ellipsometric measurements.

Metasurface-integrated vertical cavity surface-emitting lasers for programmable directional lasing emissions.

Vertical cavity surface-emitting lasers (VCSELs) have made indispensable contributions to the development of modern optoelectronic technologies. However, arbitrary beam shaping of VCSELs within a compact system has remained inaccessible until now. The emerging ultra-thin flat optical structures, namely metasurfaces, offer a powerful technique to manipulate electromagnetic fields with subwavelength spatial resolution.

Harvesting, Coupling, and Control of Single-Exciton Coherences in Photonic Waveguide Antennas.

We perform coherent nonlinear spectroscopy of individual excitons strongly confined in single InAs quantum dots (QDs). The retrieval of their intrinsically weak four-wave mixing (FWM) response is enabled by a one-dimensional dielectric waveguide antenna. Compared to a similar QD embedded in bulk media, the FWM detection sensitivity is enhanced by up to 4 orders of magnitude, over a broad operation bandwidth.