Abstract: An isolator based on a waveguide-based artificial dielectric medium is scalable to a range of desired terahertz frequencies, has non-reciprocal transmission and provides low insertion loss and high isolation at various tunable terahertz frequencies, far exceeding the performance of other terahertz isolators, and rivaling that of commercial optical isolators based on the Faraday effect. Because terahertz artificial dielectrics are low loss, inexpensive, and easy to fabricate, this approach offers a promising new route for polarization control of free-space terahertz beams in various instrumentation applications. Artificial dielectrics are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. A simple and effective strategy implements a polarizing-beam-splitter and a quarter wave plate to form a highly effective isolator.

Abstract: An isolator based on a waveguide-based artificial dielectric medium is scalable to a range of desired terahertz frequencies, has non-reciprocal transmission and provides low insertion loss and high isolation at various tunable terahertz frequencies, far exceeding the performance of other terahertz isolators, and rivaling that of commercial optical isolators based on the Faraday effect. This approach offers a promising new route for polarization control of free-space terahertz beams in various instrumentation applications. Artificial dielectrics are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. A simple and effective strategy implements a polarizing-beam-splitter and a quarter wave plate to form a highly effective isolator. Performance of the device is believed to exceed that of any other experimentally demonstrated method for isolation of back-reflections for terahertz beams.

Abstract: A polarizing beam splitter includes thin electrically conductive metal sheets each having an edge and a thickness substantially less than the wavelength ? of a terahertz signal. The sheets are arranged in a stack or array to define wave propagation passages for energy of a terahertz beam directed at a face formed by edges of the sheets, and constitutes an artificial dielectric which operates below cutoff to allow selective transmission through the passages and/or reflection from said face, separating polarization states of the beam with defined power splitting. The artificial dielectric beam splitter can be configured to operate over a broad terahertz band. The sheets are flat, without micropatterned surface features, are robust and simple to manufacture, and form a broad band polarizing beam slitter for terahertz radiation. Complete separation of the transmitted and reflected beam is achieved below cutoff by rotating the polarization of the input beam.

Abstract: An isolator based on a waveguide-based artificial dielectric medium is scalable to a range of desired terahertz frequencies, has non-reciprocal transmission and provides low insertion loss and high isolation at various tunable terahertz frequencies, far exceeding the performance of other terahertz isolators, and rivaling that of commercial optical isolators based on the Faraday effect. This approach offers a promising new route for polarization control of free-space terahertz beams in various instrumentation applications. Artificial dielectrics are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. A simple and effective strategy implements a polarizing-beam-splitter and a quarter wave plate to form a highly effective isolator. Performance of the device is believed to exceed that of any other experimentally demonstrated method for isolation of back-reflections for terahertz beams.

Abstract: A polarizing beam splitter includes thin electrically conductive metal sheets each having an edge and a thickness substantially less than the wavelength ? of a terahertz signal. The sheets are arranged in a stack or array to define wave propagation passages for energy of a terahertz beam directed at a face formed by edges of the sheets, and constitutes an artificial dielectric which operates below cutoff to allow selective transmission through the passages and/or reflection from said face, separating polarization states of the beam with defined power splitting. The artificial dielectric beam splitter can be configured to operate over a broad terahertz band. The sheets are flat, without micropatterned surface features, are robust and simple to manufacture, and form a broad band polarizing beam slitter for terahertz radiation. Complete separation of the transmitted and reflected beam is achieved below cutoff by rotating the polarization of the input beam.

Abstract: A method comprising polarizing and coupling an electromagnetic beam to a first-order transverse electric (TE1) mode with respect to a parallel plate waveguide (PPWG) integrated resonator comprising two plates and a cavity, sending the electromagnetic beam into the PPWG integrated resonator to excite the cavity by the TE1 mode and cause a resonance response, and obtaining wave amplitude data that comprises a resonant frequency, and obtaining the refractive index of fluids filling the cavity via the shift in resonant frequency.

Abstract: An apparatus comprising a parallel plate waveguide (PPWG) comprising two plates separated by a distance that supports a multimode wave, and a transmitter configured to emit a wave having a frequency from about one hundred Gigahertz (GHz) to about ten terahertz (THz) and to couple to one mode of the PPWG. Also disclosed is an apparatus comprising two plates substantially parallel to one another and separated by at least about five millimeters (mm), and an antenna coupled to the two plates and configured to transmit or receive a wave having a frequency from about one hundred GHz to about ten THz. Disclosed is a method comprising polarizing an electromagnetic beam in the first transverse electric (TE1) mode with respect to a PPWG comprising two plates, adjusting the diameter of the electromagnetic beam based on the separation between the plates, and sending the electromagnetic beam into the PPWG.

Abstract: A method comprising polarizing and coupling an electromagnetic beam to a first-order transverse electric (TE1) mode with respect to a parallel plate waveguide (PPWG) integrated resonator comprising two plates and a cavity, sending the electromagnetic beam into the PPWG integrated resonator to excite the cavity by the TE1 mode and cause a resonance response, and obtaining wave amplitude data that comprises a resonant frequency, and obtaining the refractive index of fluids filling the cavity via the shift in resonant frequency.

Abstract: An apparatus comprising a parallel plate waveguide (PPWG) comprising two plates separated by a distance that supports a multimode wave, and a transmitter configured to emit a wave having a frequency from about one hundred Gigahertz (GHz) to about ten terahertz (THz) and to couple to one mode of the PPWG. Also disclosed is an apparatus comprising two plates substantially parallel to one another and separated by at least about five millimeters (mm), and an antenna coupled to the two plates and configured to transmit or receive a wave having a frequency from about one hundred GHz to about ten THz. Disclosed is a method comprising polarizing an electromagnetic beam in the first transverse electric (TE1) mode with respect to a PPWG comprising two plates, adjusting the diameter of the electromagnetic beam based on the separation between the plates, and sending the electromagnetic beam into the PPWG.