Terahertz (THz) polarizers with robust structure and high transmittance are demonstrated using 3D-integrated circuit (IC) technologies. A Cu wire-grid polarizer is sealed and well protected by Si-bonded wafers through a low-temperature eutectic bonding method. Deep reactive-ion etching is used to fabricate the anti-reflection (AR) layers on outward surfaces of bonded wafers. The extinction ratio and transmittance of polarizers are between 20 dB and 33 dB, and 13 dB and 27 dB for 10 μm and 20 μm pitch wire-grids, respectively, and 100% at central frequency, depending on frequency and AR layer thickness. The process of polarizer fabrication is simple from mature semiconductor manufacturing techniques that lead to high yield, low cost, and potential for THz applications.

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Radiation-induced hearing loss was evaluated in 21 patients with unilateral malignant parotid tumors treated with surgery and radiotherapy. The contralateral ear was used as a control. Eight patients (38%) were found to have a reduction in static compliance of the tympanic membrane (type B tympanogram) in the irradiated ear. By audiometry, significant hearing loss was found in 9 patients (43%). These hearing losses were mainly sensorineural, as shown by a similar reduction in both air and bone conduction, although mixed-type hearing loss existed in some patients. A statistically significant difference in incidence of 67% versus 0% (p = .0085) was noted for patients with a cochlear dose of greater than or equal to 60 Gy, in comparison to those receiving doses of less than 60 Gy. A type B tympanogram was also found to be a prognostic factor for significant sensorineural hearing loss. Patients with type B tympanograms had a much higher incidence of significant sensorineural hearing loss than those with type A tympanograms (88% versus 15%, p = .02). This study clearly shows that radiotherapy can induce significant hearing impairment, especially when the cochlear doses are higher than 60 Gy.

The majority of the proposed graphene-based THz devices consist of a metamaterial that can optically interact with graphene. This coupled graphene-metamaterial system gives rise to a family of resonant modes such as the surface plasmon polariton (SPP) modes of graphene, the geometrically induced SPPs, also known as the spoof SPP modes, and the Fabry-Perot (FP) modes. In the literature, these modes are usually considered separately as if each could only exist in one structure. By contrast, in this paper, we show that even in a simple metamaterial structure such as a one-dimensional (1D) metallic slit grating, these modes all exist and can potentially interact with each other. A graphene SPP-based THz device is also fabricated and measured. Despite the high scattering rate, the effective SPP resonances can still be observed and show a consistent trend between the effective frequency and the grating period, as predicted by the theory. We also find that the excitation of the graphene SPP mode is most efficient in the terahertz spectral region due to the Drude conductivity of graphene in this spectral region.