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. Our InGaAs/InAlAs/InP ridge QCDs are designed for operation at λ = 9.124 µm. Optical waveguide simulations support the accurate optical characterization. A detailed device analysis reveals room-temperature responsivities of 111 mA/W for the 15-period and 411 mA/W for the single-period device.

Is it hyperlexia? Toward a deeper understanding of precocious reading skills in two cases of children with Autism Spectrum Disorder.

BACKGROUND: Hyperlexia is defined by a precocious and sponta-neously acquired ability to read at preschool age. Hyperlexia appears to be a wide yet not highly studied phenomenon involving different populations and possibly including children with different neuropsy-chological profiles and outcomes. METHODS: We describe two clinical cases of unrelated children diagnosed with Autism Spectrum Disorder (ASD) who both showed precocious and spontaneous reading ability. We report the neuropsy-chological assessment they underwent. RESULTS: Both children showed above average IQ, reading skills, and text comprehension, whereas one showed below average comprehen-sion only in oral text. We question whether these two phenotypes can be considered forms of hyperlexia, as defined by the most recent and consistent observations, or a subtype of ASD with hyperlexia. CONCLUSION: We conclude that our patients should be considered hyperlexic ASD, with interesting potential implications for progno-sis and rehabilitation.