We report on the implementation of 5 THz quantum well photodetector exploiting a patch antenna cavity array. The benefit of our plasmonic architecture on the detector performance is assessed by comparing it with detectors made using the same quantum well absorbing region, but processed into a standard 45° polished facet mesa. Our results demonstrate a clear improvement in responsivity, polarization insensitivity, and background limited performance. Peak detectivities in excess of 5 × 1012 cmHz1/2/W have been obtained, a value comparable with that of the best cryogenic cooled bolometers.

The spectral response of common optoelectronic photodetectors is restricted by a cutoff wavelength limit (λ c) that is related to the activation energy (or band-gap) of the semiconductor structure (or material) (∆) through the relationship: λ c = hc/∆. This spectral rule dominates device design and intrinsically limits the long wavelength response of a semiconductor photodetector. Here, we report a new, long wavelength photodetection principle based on a hot-cold hole energy transfer mechanism that overcomes this spectral limit. Hot carriers injected into a semiconductor structure interact with cold carriers and excite them to higher energy states. This enables a very long-wavelength infrared response. In our experiments, we observe a response up to 55 µm, which is tunable by varying the degree of hot-hole injection, for a GaAs/AlGaAs sample with ∆ = 0.32 eV (equivalent to 3.9 µm in wavelength).

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We have studied the effect of both long-and short-range disorder on frequency scaling of the diagonal magnetoconductivity σ xx in the integer quantum Hall effect regime of two-dimensional electrons confined to Al x Ga 1-x As/Al 0.33 Ga 0.67 As single heterostructures for two Al concentrations, x. Within the frequency range 100 MHz f 20 GHz and for a temperature T = 35 mK, we found that the frequency scaling exponent c changes from 0.6 ± 0.05 for a GaAs/Al 0.33 Ga 0.67 As heterostructure, where the disorder is dominated by long-range ionized impurity potentials, to c = 0.42 ± 0.06 for Al 0.015 Ga 0.985 As/Al 0.33 Ga 0.67 As heterostructures, where the dominant contribution to the disorder is from short-range alloy potential fluctuations. This value of c allows us to estimate the dynamical scaling exponent as z = 1 ± 0.13.

We demonstrate the efficient coupling of single photons emitted by single quantum dots (QDs) in a photonic crystal cavity (PhCC) to a ridge waveguide (RWG). Using a single-step lithographic process with an optimized tapering, up to 70% coupling efficiency between the photonic crystal waveguide and the RWG was achieved. The emission enhancement of single QDs inside an in-line PhCC coupled via the RWG to a single-mode fiber was observed. Single-photon funneling rates around 3.5 MHz from a single QD into the RWG were obtained. This result is a step toward the realization of a fully functional quantum photonic integrated circuit.