Planar THz quasioptics

Dai, Jianming; Coleman, Steven M.; Grischkowsky, D.

doi:10.1063/1.1781357

Cited by 16 publications

(19 citation statements)

References 9 publications

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“…Parallel-plate transmission lines have been used with lenses to obtain highly focused THz radiation comparable to that expected for a 3-D optical element in free-space (Dai et al, 2004). This method shows promise for coupling energy from the common junction because it would be possible to obtain an impedance of 50 Ω for TEM mode propagation at THz frequencies with a cut-off frequency of zero Hz (Ghamsari et al, 2008).…”

Section: Other Types Of Antennasmentioning

confidence: 99%

Broadband Terahertz Source Based on Photomixing in Laser-Assisted Field Emission with Clusters of Carbon Nanotubes

Hagmann¹

2010

Carbon Nanotubes

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Section: Other Types Of Antennasmentioning

confidence: 99%

Broadband Terahertz Source Based on Photomixing in Laser-Assisted Field Emission with Clusters of Carbon Nanotubes

Hagmann¹

2010

Carbon Nanotubes

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“…1͒ and propagates along it until it meets an out-coupling optical element and goes to the detector. Diffractive lenses as coupling optical elements have many advantages [3][4][5] and have been suggested also in the context of quasi-optics 6 for rapidly expanding terahertz technology. 7 However, their intrinsic dependence of optical properties on the wavelength-chromaticity-poses difficult problems.…”

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confidence: 99%

Mechanical means for temperature compensation of planar diffractive optical interconnects: feasibility study

Socol¹

2006

Opt. Eng

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Abstract. Planar diffractive optical interconnects have many advantages, however, their inherent chromaticity leads to temperature instability due to the wavelength shift of laser diodes' radiation. This shift can be compensated if the optical interconnect is bended in an appropriate direction with curvature proportional to the relative wavelength shift. The bending can be performed by attaching an additional plate to the element with a different thermal expansion coefficient. Theoretical analysis and ray tracing are reported. In the semiconductor industry, there is a continually aggravating problem of increasing communication volume. Optical interconnection technology is seen as a prime option for solving this problem.1,2 In planar optical interconnects ͑POI͒ light is injected ͑by an in-coupling optical element͒ into a transparent slab ͑light guide͒ at a total internal reflection angle ͑ in Fig. 1͒ and propagates along it until it meets an out-coupling optical element and goes to the detector. Diffractive lenses as coupling optical elements have many advantages [3][4][5] and have been suggested also in the context of quasi-optics 6 for rapidly expanding terahertz technology.7 However, their intrinsic dependence of optical properties on the wavelength-chromaticity-poses difficult problems.8 Chromaticity leads also to temperature instability. Namely, the wavelength of semiconductor lasers is temperature-dependent. Temperature change causes wavelength shift, therefore the laser beam as deflected by the diffractive in-coupling optical element deviates from its desired path and can miss the out-coupling element. For example, for a typical 850-nm vertical-cavity surfaceemitting lasers ͑VCSEL͒ source the wavelength shift is d / dT = 0.06 nm/ K, 9 i.e., relative wavelength shift is ͑1/͒͑d / dT͒ϳ7 ϫ 10 −5 K −1 . If POI was assembeled at 20°C, the working temperature is 140°C ͑Max3905 from Dallas Semiconductors, e.g.͒, and the POI length is 10 cm, the resulting beam deviation is about 1.7 mm ͑see below the calculation͒. This temperature instability is specific for diffracive POI since other thermal effects are much less: e.g., for fused silica the explicit refraction index temperature dependence is −3 ϫ 10 −6 K −1 . 10 The implicit temperature dependence ͑due to the refraction index wavelength dependence dn / d and the laser wavelength shift d / dT͒ is even smaller: dn / d =4ϫ 10 −5 nm −1 , 10 leading to dn / dT = ͑dn / d͒͑d / dT͒ = 2.4ϫ 10 −7 K −1 . We propose to fix this problem by bending POI in accordance to the temperature change. We suppose that POI and the laser have the same temperature since they are close to each other. A simple bending scheme is absolutely passive and implies attaching to POI a second plate, having different thermal expansion coefficient ͑in mass production, the attachment may be done by lamination technology 11 ͒. The curvature of this bending is proportional to the temperature change ͑as long as the thermal expansion can be considered as linear with temperature͒. As long as the laser wavelen...

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“…3,4 With these developments, planar THz quasioptics and interconnects have also been realized. 5,6 THz waveguides can also be used for spectroscopy purposes.…”

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confidence: 99%

“…The entire waveguide structure is placed at the confocal THz beam waist midway between the two off-axis paraboloidal mirrors. 6 The THz-TDS system and the waveguide structure are placed in an air-tight box purged with dry air to mitigate the absorption lines of water vapor.…”

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confidence: 99%

Adiabatic compression of parallel-plate metal waveguides for sensitivity enhancement of waveguide THz time-domain spectroscopy

Zhang

Grischkowsky

2005

Applied Physics Letters

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Planar THz quasioptics

Cited by 16 publications

References 9 publications

Broadband Terahertz Source Based on Photomixing in Laser-Assisted Field Emission with Clusters of Carbon Nanotubes

Broadband Terahertz Source Based on Photomixing in Laser-Assisted Field Emission with Clusters of Carbon Nanotubes

Mechanical means for temperature compensation of planar diffractive optical interconnects: feasibility study

Adiabatic compression of parallel-plate metal waveguides for sensitivity enhancement of waveguide THz time-domain spectroscopy

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