275 research outputs found
Sequential resonant tunneling in quantum cascade lasers
A model of sequential resonant tunneling transport between two-dimensional
subbands that takes into account explicitly elastic scattering is investigated.
It is compared to transport measurements performed on quantum cascade lasers
where resonant tunneling processes are known to be dominating. Excellent
agreement is found between experiment and theory over a large range of current,
temperature and device structures
Strong terahertz absorption using SiO2/Al based metamaterial structures
The article of record as published may be found at http://dx.doi.org/10.1063/1.3693407Metamaterial absorbers with nearly 100% absorption in the terahertz (THz) spectral band have been designed and fabricated using a periodic array of aluminum (Al) squares and an Al ground plane separated by a thin silicon dioxide (SiO2) dielectric film. The entire structure is less than 1.6 mm thick making it suitable for the fabrication of microbolometers or bi-material sensors for THz imaging. Films with different dielectric layer thicknesses exhibited resonant absorption at 4.1, 4.2, and 4.5 THz with strengths of 98%, 95%, and 88%, respectively. The measured absorption spectra are in good agreement with simulations using finite element modeling
Analytical coupled-wave model for photonic crystal quantum cascade lasers
A coupled-wave model is developed for photonic-crystal quantum cascade
lasers. The analytical model provides an efficient analysis of full
three-dimensional large-area device structure, and the validity is confirmed
via simulations and previous experimental results.Comment: 21 pages and 8 figure
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