Broadband terahertz characterization of the refractive index and absorption of some important polymeric and organic electro-optic materials

Cunningham, Paul D.; Valdes, Nestor N.; Vallejo, Felipe A.; Hayden, L. Michael; Polishak, Brent M.; Zhou, Xinghua; Luo, Jingdong; Jen, Alex K.‐Y.; Williams, Jarrod; Twieg, Robert J.

doi:10.1063/1.3549120

Cited by 374 publications

(186 citation statements)

References 20 publications

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“…In the second set, we assume that the imaginary values of the tabulated data are increased by a factor of 4. We note that such absorption above the nominal PTFE absorption is comparable to the absorption values reported for other polymers [30,31]. A detailed description of the simulation can be found in Appendix: Eigenmode numerical analysis.…”

Section: Transmission Losses and Field Distribution Inside The Waveguidesupporting

confidence: 50%

Silver-Coated Teflon Tubes for Waveguiding at 1–2 THz

Navarro‐Cía

Melzer

Harrington

et al. 2015

J Infrared Milli Terahz Waves

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Realization of single-mode low-loss waveguides for 1.0-2.0 THz remains a challenging problem due to large absorption in most dielectrics and ohmic losses in metals. To address this problem, we investigate dielectric-lined hollow metallic waveguides fabricated by coating 1-mm diameter 38-μm-thick polytetrafluoroethylene tubes with silver. These waveguides support a hybrid HE 11 mode, which exhibits low attenuation and low dispersion. Quasisingle-mode propagation is achieved in the band of 1.0-1.6 THz, in which the hybrid HE 11 mode is supported by the waveguide. In this band, the experimentally measured loss is 20 dB/m (~0.046 cm −1 ), whereas the numerically computed loss is~7 dB/m (~0.016 cm). The difference is attributed to additional losses in the dielectric layer, which can be reduced by using alternative polymers.

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Section: Transmission Losses and Field Distribution Inside The Waveguidesupporting

confidence: 50%

Silver-Coated Teflon Tubes for Waveguiding at 1–2 THz

Navarro‐Cía

Melzer

Harrington

et al. 2015

J Infrared Milli Terahz Waves

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“…By comparison, the previous demonstration of a random QCL (using an random air-hole design at mid-IR frequencies 42 , or using hyperuniform pillar structure design 18 ) exhibited only 2-3 peaks in the r FF  spectrum. Based on these results, even more strongly multi-modal behavior could be achieved in three ways: (i) by replacing the BCB with a lower-loss supporting material, such as cyclic olefin copolymer 43,44 , which would significantly increase the modal Q factors; (ii) by connecting the pillars with dielectric veins, which would reduce or eliminate the need for the BCB support 31 ; and (iii) by increasing the short-range order through more sophisticated placement algorithms, such as molecular dynamics-based jam packing, which would again increase the modal Q factors.…”

Section: Discussionmentioning

confidence: 99%

Designer Multimode Localized Random Lasing in Amorphous Lattices at Terahertz Frequencies

Zeng

Liang

et al. 2016

ACS Photonics

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Random lasers are a special class of laser in which light is confined through multiple scattering and interference process in a disordered medium, without a traditional optical cavity. They have been widely studied to investigate fundamental phenomena such as Anderson localization, and for applications such as speckle-free imaging, benefitting from multiple lasing modes. However, achieving controlled localized multi-mode random lasing at long wavelengths, such as in the terahertz (THz) frequency regime, remains a challenge.Here, we study devices consisting of randomly-distributed pillars fabricated from a quantum cascade gain medium, and show that such structures can achieve transversemagnetic polarized (TM) multi-mode random lasing, with strongly localized modes at THz frequencies. The weak short-range order induced by the pillar distribution is sufficient to ensure high quality-factor modes that have a large overlap with the active material.Furthermore, the emission spectrum can be easily tuned by tailoring the scatterer size and filling fraction. These "designer" random lasers, realized using standard photolithography 2 techniques, provide a promising platform for investigating disordered photonics with predesigned randomness in the THz frequency range, and may have potential applications such as speckle-free imaging.

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“…The organic dyes examined here are in the push-pull DCDHF class which we have previously used in a variety of optoelectronic applications [27][28][29] . Amongst these DCDHF dyes the specific substance DCDHF-6-V (CAS 634202-68-9) has been most thoroughly examined during our initial studies.…”

Section: Methodsmentioning

confidence: 99%

Coupling of exciton-polaritons inlow−Qcoupled microcavities beyond the rotating wave approximation

et al. 2015

Self Cite

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We have demonstrated coupling between a pair of ultrastrong light-matter coupled microcavities composed of neat glassy organic dye films between metallic (silver) mirrors at room temperature. Based upon our modified coupled oscillator model, we have observed that the degeneracy between the Rabi splittings associated with the symmetric and antisymmetric cavity modes is broken by the higher-order anti-resonant terms in the Hamiltonian associated with the breakdown of the rotating wave approximation in the ultrastrong coupling regime. These results are in quantitative agreement with both experiment and transfer matrix modeling. The component cavities are characterized by Q factors around 12 and display a large vacuum Rabi splitting around 1.12 eV between the upper and lower polariton branches, which is about 52% of the excited state energy, thus indicating ultrastrong coupling in each individual cavity. This large splitting is due to the large oscillator strength of the neat dye glass. We have also observed large polariton-induced incidence-side asymmetry in reflection spectra in a coupled cavity pair with one cavity having no exciton.

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Broadband terahertz characterization of the refractive index and absorption of some important polymeric and organic electro-optic materials

Cited by 374 publications

References 20 publications

Silver-Coated Teflon Tubes for Waveguiding at 1–2 THz

Silver-Coated Teflon Tubes for Waveguiding at 1–2 THz

Designer Multimode Localized Random Lasing in Amorphous Lattices at Terahertz Frequencies

Coupling of exciton-polaritons inlow−Qcoupled microcavities beyond the rotating wave approximation

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