High Resolution Absorption Coefficient and Refractive Index Spectra of Carbon Monoxide Gas at Millimeter and Submillimeter Wavelengths

Al-Moayed, N.; Afsar, M.N.

doi:10.1109/imtc.2005.1604511

Cited by 3 publications

(5 citation statements)

References 18 publications

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“…(A more accurate expression for S(t) that preserves the multi-heterodyne frequency-domain picture is given in Eq. (12) and Ref. [19].)…”

Section: Configuration Of Dual-comb Spectrometermentioning

confidence: 93%

“…[6][7][8], the output of one comb is transmitted through a sample and then combined with a second "local oscillator" (LO) comb source to measure the full complex response of a sample (i.e., phase and amplitude) with the frequency resolution and accuracy inherent to the comb source. In the time domain, the approach mirrors time-domain spectroscopy [7] or dispersive Fourier transform spectroscopy (FTS) [9][10][11][12]. In the frequency domain, the approach resembles a massively parallel laser heterodyne spectrometer, where each pair of comb teeth contributes to the heterodyne signal at a specific rf frequency [13].…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity of coherent dual-comb spectroscopy

2010

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Coherent dual comb spectroscopy can provide high-resolution, high-accuracy measurements of a sample response in both magnitude and phase. We discuss the achievable signal-to-noise ratio (SNR) due to both additive white noise and multiplicative noise, and the corresponding sensitivity limit for trace gas detection. We show that sequential acquisition of the overall spectrum through a tunable filter, or parallel acquisition of the overall spectrum through a detector array, can significantly improve the SNR under some circumstances. We identify a useful figure of merit as the quality factor, equal to the product of the SNR, normalized by the square root of the acquisition time, and the number of resolved frequency elements. For a single detector and fiber-laser based system, this quality factor is 10(6) - 10(7) Hz(1/2).

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“…(A more accurate expression for S(t) that preserves the multi-heterodyne frequency-domain picture is given in Eq. (12) and Ref. [19].)…”

Section: Configuration Of Dual-comb Spectrometermentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Sensitivity of coherent dual-comb spectroscopy

2010

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“…Precise determination of ε and n is strongly required by both designers and manufacturers of antenna and radar systems, therefore, numerous efforts that have been put in development of different laboratory setups. An advantage has been given to various resonator techniques, such as the open resonator systems (ORS) [1, 2] or the dispersive Fourier transform spectrometers (DFTS) [3–5], rather than to the waveguide (WG) methods [6–8]. In particular, the WG technique requires a specific preparation of the sample under test, whereas the air gap between the WG and the sample usually leads to a large error in the measurement result.…”

Section: Introductionmentioning

confidence: 99%

“…In comparison, the resonator technique may be considered as one of the most accurate methods being applied at the millimeter–submillimeter wavelengths to study transparent materials. The great advantage of DFTS is that this is the only known technique, which simultaneously measures both the refractive index and the absorption coefficient with a high precision [3, 5]. There are also several other methods described (e.g., in Refs 9–11…”

Section: Introductionmentioning

confidence: 99%

Interferometry technique for refractive index measurements at subcentimeter wavelengths

Andrushchak

Syrotynsky

Karbovnyk

et al. 2011

Micro & Optical Tech Letters

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tends to be sensitive to the tolerances in both the design and fabrication, some related sensitivity analyses based on the proposed parameters have been performed, and it is found that the tuning distortion caused by the variation of resonant frequency of each resonator have some noticeable effect on the desired response. CONCLUSIONThis letter presents the synthesis of a narrow-band bandpass filter for CDMA2000 communications systems, which has a 14pole general Chebyshev function response with a passband of 11.2 MHz at 830 MHz. The coupling matrix of the filter is derived from cost function using nonlinear LM algorithm. The filter response with two pairs of TZs for group delay self-equalization and one pair of TZs at finite frequencies for high selectivity requirement is implemented by using three CQ coupling structures. The frequency responses demonstrating a good agreement between the measured and the simulated specifications are obtained. The proposed method can be further exploited for various mobile communication system applications.

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“…Therefore a sacrifice has to be made between resolution and signal-to-noise ratio as double sided interferograms reduce the resolution by half due to the fact that they take two measurements of interferogram points every scan. Afsar [2][3], a pioneer in the field of dispersive Fourier transform spectroscopy, constructed a high resolution millimeter and submillimeter wave dispersive Fourier transform spectrometer (DFTS) for use in our laboratory to measure transmission, absorption coefficient, and refractive index spectra of gas molecules [4]. This line diagram of this setup can be seen clearly in Fig.…”

Section: Introductionmentioning

confidence: 99%

Precision high resolution fourier transform spectroscopy of greenhouse gases at millimeter and submillimeter wavelengths

Al-Moayed¹,

Khan²,

Afsar³

2008

2008 Conference on Precision Electromagnetic Measurements Digest

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Dispersive Fourier transform spectroscopy (DFTS) provides us with a very effective technique for the measurement of absorption and refractive index spectra of environmentally hazardous gases. This paper presents the rotational transition lines and refractive index spectra of Nitrous Oxide gas as a function of varying pressure using DFTS for the very first time. The relationship between the variation of the pressure and the change in the absorption spectrum is examined and discussed in detail. Nitrous Oxide (NO 2) gas is considered a harmful greenhouse gas and is the third largest contributor to overall global warming after Carbon Dioxide and Methane. This study demonstrates the ability of our setup to accurately identify and characterize NO 2 gas at differing pressures over a broadband frequency spectrum. These findings presented from 300 GHz-900 GHz are therefore of great importance in the ongoing struggle to battle global warming.

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High Resolution Absorption Coefficient and Refractive Index Spectra of Carbon Monoxide Gas at Millimeter and Submillimeter Wavelengths

Cited by 3 publications

References 18 publications

Sensitivity of coherent dual-comb spectroscopy

Sensitivity of coherent dual-comb spectroscopy

Interferometry technique for refractive index measurements at subcentimeter wavelengths

Precision high resolution fourier transform spectroscopy of greenhouse gases at millimeter and submillimeter wavelengths

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