Low-loss subwavelength plastic fiber for terahertz waveguiding

Abstract

We report a simple subwavelength-diameter plastic wire, similar to an optical fiber, for guiding a terahertz wave with a low attenuation constant. With a large wavelength-to-fiber-core ratio, the fractional power delivered inside the lossy core is reduced, thus lowering the effective fiber attenuation constant. In our experiment we adopt a polyethylene fiber with a 200 microm diameter for guiding terahertz waves in the frequency range near 0.3 THz in which the attenuation constant is reduced to of the order of or less than 0.01 cm(-1). Direct free-space coupling efficiency as high as 20% can be achieved by use of an off-axis parabolic mirror. Furthermore, all the plastic wires are readily available, with no need for complex or expensive fabrication.

Thermally generated long-lived quantum correlations for two atoms trapped in fiber-coupled cavities

“…The transition frequency of the atom is chosen to be midinfrared (MIR), i.e. ω a /2π = 4THz and hence, for experimental purposes the coupling between the distant cavities can be realized by using the modern resources of IR fiber optics, e. g. hollow glass waveguides [20], plastic fibers [21], etc. We choose the range of MIR frequencies in order to limit the thermal reservoir only up to room temperature (300K), which corresponds to a thermal photon.…”

Microwire fibers for low-loss THz transmission

“…In the optical regime, there are materials that have low material absorption. However, the terahertz regime is lacking such materials for proper waveguiding, therefore reducing the fractional power inside the dielectric core-the microwire operating regime-is a way of improving the material absorption 15 .…”

“…10, 14 Chen et al 15 have recently reported loss values less than 0.01 cm −1 near 0.3 THz in plastic fibers. The concept of THz guided propagation in these fibers is similar to optical nanowire fibers.…”

Porous-core honeycomb bandgap THz fiber

“…Terahertz waveguides have consequently also attracted attention, both for distributing the radiation and as functional devices [2]. Apart from hollow metallic and glass waveguides [3,4], the material of choice when making terahertz waveguides is polymer, i.e., poly(methyl-methacrylate) (PMMA) [5], Teflon [6], high-density polyethylene (HDPE) [7,8], and Topas [9]. The reasons for this material choice are that polymers have the lowest loss of most materials in the THz range and they are for the most part easy to machine.…”

“…Currently there is much research invested in lowering the loss by forcing a large part of the radiation to propagate in air while still being confined to a waveguide, i.e., subwavelength fiber [8], porous fibers [10,11], and hollow-core fibers. Of these, the hollow-core fiber is the least sensitive to outside perturbations, and thus the fiber can be handled without altering the propagation properties.…”