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We design, fabricate and characterize dual-band terahertz (THz) metamaterial absorbers with high absorption based on a structures consisting of a cobalt silicide (Co-Si) ground plane, a parylene-C dielectric spacer and a metal top layer. By combining two periodic metal resonators that couple separately within a single unit cell, a polarization-independent absorber with two distinct absorption peaks was obtained. By varying the thickness of the dielectric layer, we obtain absorptivity of 0.76 at 0.76THz and 0.97 at 2.30THz, which indicates the Co-Si ground plane absorbers present good performance.

Si0.5Ge0.5/Si quantum cascade structures have been deposited by low-energy plasma-enhanced CVD according to a bound-to-continuum design and characterized by high resolution x-ray diffraction and transmission electron microscopy. Electroluminescence from the active region is peaked around 2.5 THz (~10 meV) and exhibits Stark shift and polarization dependence.

The emission and absorption characteristics of boron-doped and phosphorous-doped silicon at terahertz frequencies are investigated. Different doping concentrations are considered and individual terahertz optical transitions are identified. The effect of temperature is considered.

Nanosecond routing in a 64/spl times/64 optical phased array switch is reported. Further testing of the switch shows transmission capability of four 40 Gb/s WDM channels through a single switch path, with power penalty of 0.3 dB per channel. The optical path performance at high bit rate and data rate scalability of the switch is demonstrated for the first time. This performance indicates the possibility of switch implementation in Terabit routing systems. Furthermore, the results presented demonstrate the wavelength, data rate and format transparency of the switch, opening the possibility for the switch to be used in optical IP networks.