Polarimetry is a well-developed technique in radar based applications and stand-off spectroscopic analysis at optical
frequencies. Extension to terahertz (THz) frequencies could provide a breakthrough in spectroscopic methods since the
THz portion of the electromagnetic spectrum provides unique spectral signatures of chemicals and biological molecules,
useful for filling gaps in detection and identification. Distinct advantages to a THz polarimeter include enhanced image-contrast
based on differences in scattering of horizontally and vertically polarized radiation, and measurements of the
dielectric response, and thereby absorption, of materials in reflection in real-time without the need of a reference
measurement. To implement a prototype THz polarimeter, we have developed low profile, high efficiency metamaterial-based
polarization control components at THz frequencies. Static metamaterial-based half- and quarter-wave plates
operating at 0.35 THz frequencies were modeled and fabricated, and characterized using a MHz resolution, continuous-wave
spectrometer operating in the 0.09 to 1.2 THz range to verify the design parameters such as operational frequency
and bandwidth, insertion loss, and phase shift. The operation frequency was chosen to be in an atmospheric window
(between water absorption lines) but can be designed to function at any frequency. Additional advantages of
metamaterial devices include their compact size, flexibility, and fabrication ease over large areas using standard
microfabrication processing. Wave plates in both the transmission and reflection mode were modeled, tested, and
compared. Data analysis using Jones matrix theory showed good agreement between experimental data and simulation.
Metamaterial and plasmonic composites have led to the realization that new possibilities abound for creating materials
displaying functional electromagnetic properties not realized by nature. Recently, we have extended these ideas by
combining metamaterial elements - specifically, split ring resonators - with MEMS technology. This has enabled the
creation of non-planar flexible composites and micromechanically active structures where the orientation of the
electromagnetically resonant elements can be precisely controlled with respect to the incident field. Such adaptive
structures are the starting point for the development of a host of new functional electromagnetic devices which take
advantage of designed and tunable anisotropy.
Recent advances in MEMS and focal plane array (FPA) technologies have led to the development of manufacturing microbolometers monolithically on a readout integrated circuit (ROIC). In this work, both numerical and finite element methods were performed to simulate the transient electrical and mechanical responses of resistive microbolometer FPAs made by several TCR (thermal coefficient of resistance) materials including a-Si, VOx and semiconducting YBCO. Numerical simulation shows that the pulsed bias readout mode in resistive microbolometer FPAs causes a non-steady-state of the system during the operation. As a result, NETD decreases with the increasing pulse width. In FPAs, the array size, frame rate, ROIC and mechanical reliability set the up-limit to the pulse width. The transient mechanical response for three microbolometer configurations was investigated using finite element modeling. The biased pulse results in membrane bending along the z-axis for the symmetric extended configuration (Type I), or twisting in three axes for the asymmetric extended configuration (Type II) due to the constraint force from the supporting arms. The square configuration (Type III) exhibits the smallest deformation and minimum shear stress at the sharp geometries. a-Si microbolometer generates higher shear stress than other microbolometers with the same square configuration.