Off-axis behavior of an infrared meander-line waveplate

Abstract

An infrared meander-line waveplate has been modeled and measured over the 8 to 12 microm spectral band in terms of its differential phase delay, axial ratio of the output polarization ellipse, and power throughput for angles of incidence between 0 degrees and 60 degrees. The study has been performed for planes of incidence parallel and perpendicular to the meander-line axis. The main significance is that the phase delay remains almost unaffected by the angle of incidence. Infrared meander-line retarders can thus be used well beyond the paraxial range as in low-f/# optical systems and in non-normal-incidence applications.

Monochromatic aberrations in resonant optical elements applied to a focusing multilevel reflectarray

“…This corresponds quite well with the paraxial range that is commonly used in conventional optical design. This general behavior was also obtained when checking the angular application range of meander-like resonant structures for polarization control [14]. Then, the phase shift begins to depart from the one obtained at normal incidence.…”

“…The second term is a third-order aberration similar in symmetry to spherical aberration, but having a cubic dependence on aperture instead of the usual 4th-power dependence. In situations where the angular dependence may depend on the polarization of the incident field (as happens with meander-line structures [14]), the fitting coefficients A and B in Eqs. (4)- (6), may change when considering the polarization state of the incoming light.…”

Optical properties of metallic films

“…essentially this means that we are altering the effective permittivity of the surface. Some good examples of practical metamaterial work in the IR include the control of spectral transmission [65], reflection [66], absorption [67], emission [68,69] reflected phase [70], emitted phase [71], as broad-band wave plates [72] and for molecular detection [73].…”

Comparison of quarter-wave retarders over finite spectral and angular bandwidths for infrared polarimetric-imaging applications

“…1(b)) selected for this study represents a field of technology that has not yet been thoroughly investigated with regard to IR polarimetric-imaging. This device is the same 2-layer QWP component that was presented in [12], which is expected to exhibit achromatic polarimetric characteristics and angle-insensitive behavior, based upon past performance [12][13][14][15]. Multilayer meanderline QWPs have technological potential that could be employed in thermal IR po-larimeters, especially considering that they can be fabricated into a compact planar form factor that facilitates integration with other polarization devices and pixelated IR sensors.…”

“…The increase in beam ellipticity is particularly due to the disparity between the surface impedance discontinuities of the TE and TM modes of the meanderline structure, which is intrinsically anisotropic due to the geometrical configuration of the metallic scatterers (see Fig. 1(b)) [12][13][14][15]. Secondly, the phase shift of the meanderline QWP exhibits two noticeable dips in its spectrum that signify further departure from ideal behavior.…”