Polarization-Resolved THz Imaging With Orthogonal Heterostructure Backward Diode Detectors

A fully integrated lens-coupled dual-polarization detector for imaging was designed, fabricated, and characterized in the terahertz (THz) region. Two zero-bias heterostructure backward diodes were monolithically integrated into a planar dualpolarization annular-slot antenna. An impedance matching network consisting of an interdigitated dc block and shorted stubs was implemented for maximum power transfer. The fabricated chip was then mounted on an extended hemispherical silicon lens for high antenna efficiency. The performance of the integrated detector has been characterized at 200 GHz. The detector module can simultaneously measure the two orthogonal linear-polarized components of the incident THz waves, and hence obtain the polarization direction. On the basis of this polarimetric detection, polarization-resolved imaging of a Gaussian beam, as well as birefringent samples, was performed using the integrated detectors. The angular resolution of the polarization detection has been demonstrated to be as small as 3 degrees. The single-pixel detector demonstrated here is amenable to array applications for THz focal-plane arrays that will have a significant impact on a wide range of remote sensing, through-barrier imaging, and detection/identification applications.

Automated summary

A fully integrated lens-coupled dual-polarization detector for imaging in the terahertz region was designed, fabricated, and characterized. The detector module can simultaneously measure the two orthogonal linear-polarized components of the incident THz waves, and polarization-resolved imaging of Gaussian beam and birefringent samples was performed. The single-pixel detector demonstrated here is suitable for array applications and has significant impact on remote sensing, through-barrier imaging, and detection/identification applications.