Pulsed Terahertz Signal Reconstruction

Fletcher, J. R.; Swift, G. Peter; Dai, DeChang; Chamberlain, J.M.; Upadhya, P. C.

doi:10.1063/1.2818361

Cited by 17 publications

(8 citation statements)

References 6 publications

(5 reference statements)

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“…This approach utilizes extra measurements to differentially remove the undesired effects, including echoes, from the signal [15]. To do this, the method requires a measurement from exactly the same setup, when the effect of interest is somehow removed [16].…”

Section: Possible Solutionsmentioning

confidence: 99%

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Signal Recovery in Pulsed Terahertz Integrated Circuits

Heidari¹,

Neshat²,

Saeedkia³

et al. 2010

PIER

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Abstract-In this article, a time-domain calibration procedure is proposed for pulsed Terahertz Integrated Circuits (TIC) used in onchip applications, where the conventional calibration methods are not applicable. The proposed post-detection method removes the unwanted linear distortions, such as interfering echoes and frequency dispersion, by using only one single-port measurement. The method employs a wave-transfer model for analysis of the TIC, and the model parameters are obtained by a proposed blind estimation algorithm. A complete implementation of the method is demonstrated for a fabricated TIC, when used in an on-chip sensing application. The features of interest in the measured signal, such as absorption lines, can be masked or weakened by the distortion of the THz signal happening in a TIC. The proposed signal recovery approach improves the detection of those otherwise hidden features, and can significantly enhance the performance of existing TICs. To show the effectiveness of the proposed de-embedding method, numerical results are presented for simulated and measured signals. The method presented in this article is enabling for accurate TIC applications, and can be utilized to optimally design novel TIC structures for specific purposes.

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Section: Possible Solutionsmentioning

confidence: 99%

“…For example, in Ref. [15] the sample is substituted with a mirror to keep the echo structure the same.…”

Section: Possible Solutionsmentioning

confidence: 99%

Signal Recovery in Pulsed Terahertz Integrated Circuits

Heidari¹,

Neshat²,

Saeedkia³

et al. 2010

PIER

View full text Add to dashboard Cite

show abstract

“…Several hardware methods have been proposed to overcome this echo issue but do not completely A resolve the problem: THz dielectric anti-reflection coating [10] have been demonstrated but have a narrow bandwidth and thus not adapted for broadband emission; broadband thin metal coatings [11] are difficult to realize and introduce important losses. Alternative approaches consist in numerical methods, either by deconvolution with a reference signal [12], [13], or echo cancelation with a deconvolution algorithm [14], [15]. However, those methods require either a careful calibration of the reference, or an assumption of the dispersion properties of the substrate, respectively.…”

Section: Introductionmentioning

confidence: 99%

Echo-less Photoconductive Antenna sources for High-resolution Terahertz Time-domain Spectroscopy

Maussang

Brewer

Palomo

et al. 2016

Conference on Lasers and Electro-Optics

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Abstract-Interdigitated photoconductive antennas are powerful and easy-to-use sources of terahertz radiation for timeresolved spectroscopy. However, the emission of unwanted echoes, resulting from reflections of the emitted pulse in the antenna substrate, inherently limits the spectroscopic frequency resolution. A novel interdigitated photoconductive antenna that suppresses unwanted echoes from the substrate, without power losses, is proposed and demonstrated. This is realized through a buried metal geometry where a metal plane is placed at a subwavelength thickness below the surface antenna structure and GaAs active layer. In a reflection geometry this effectively eliminates echoes, permitting high resolution spectroscopy to be performed. As a proof-of-principle, the 101 -212 and the 212 -303 rotational lines of water vapor have been spectrally resolved with the new buried metal antenna, which are unresolvable with a standard antenna. In addition, as no THz field is lost to the substrate and reflections, the terahertz peak electric field amplitude is enhanced by a factor of three compared to a standard design in the equivalent reflection geometry.Index Terms-Terahertz antenna, terahertz photoconductive sources, terahertz radiation, ultrafast photoconductors, submillimeter wave devices.

show abstract

“…Several A resolve the problem: THz dielectric anti-reflection coating [10] have been demonstrated but have a narrow bandwidth and thus not adapted for broadband emission; broadband thin metal coatings [11] are difficult to realize and introduce important losses. Alternative approaches consist in numerical methods, either by deconvolution with a reference signal [12], [13], or echo cancelation with a deconvolution algorithm [14], [15]. However, those methods require either a careful calibration of the reference, or an assumption of the dispersion properties of the substrate, respectively.…”

Section: Introductionmentioning

confidence: 99%