Possibility of the detection and identification of substance at long distance using the noisy reflected THz pulse under real conditions

Trofimov, Vyacheslav A.; Varentsova, Svetlana A.; Trofimov, Vyacheslav A.

doi:10.1117/12.2177991

Cited by 6 publications

(9 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Below, accordingly to our previous investigations [28]- [35] we choose parameters of window length, its shift and power k in the following way: the window length T = 2.8 ps, the window shift Δ = 0.2 ps and k = 20.…”

Section: Modified Integral Correlation Criteriamentioning

confidence: 99%

High effective THz-TDS method for the detection and identification of substances in real conditions

et al. 2016

Self Cite

View full text Add to dashboard Cite

Low efficiency of the standard THz-TDS method for the detection and identification of substances is demonstrated. For this purpose, we use a few examples. In the first example, we model the noisy THz signals transmitted through the amphetamine-type stimulant in real conditions. Namely, with a temperature 18° C, the relative humidity of about 50 % and the distance between the parabolic mirror and the object about of 3.5 meters. We show that the standard THz-TDS method reveals the spectral features of many neutral substances and explosives in the noisy THz signals from the illicit stimulant MA, at the same time this method is not able to detect the presence of this stimulant in the noisy signals. The second example is the detection and identification of plastids with inhomogeneous surface in reflection mode. We show that inhomogeneous surface distorts spectral characteristics of the reflected THz signal main pulse, which cannot be used for the detection and identification of the plastids by means of the THz TDS method. In the last example we show that even under laboratory conditions (at short distance from the receiver), THz TDS detects in the semiconductors the absorption frequencies, which belong to both hazardous and neutral substances. To overcome this disadvantage, we propose to use the time-dependent spectrum of the THz pulse, transmitted through or reflected from a substance. For quality assessment of the presence of the standard substance absorption frequency in the signal under analysis, we use time-dependent integral correlation criteria. The influence of aperture placed in front of the sample on spectral properties of silicon wafers with different resistivity is demonstrated as well.Keywords: reflected and transmitted THz pulse, noisy THz pulse, method of spectral dynamics analysis, integral correlation criteria, identification of explosives and drugs. *vatro@cs.msu.ru; phone 7 495 939-5255; fax 7 495 939-2597

show abstract

Section: Modified Integral Correlation Criteriamentioning

confidence: 99%

High effective THz-TDS method for the detection and identification of substances in real conditions

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Using the standard THz TDS method under such a condition can lead to a large number of false positive alarms during security screening, which renders its effectiveness low. At the same time, a possibility of the substance detection and identification by means of SDA-method together with several integral correlation criteria (ICC) using noisy THz signals with SNR about 0.5 was demonstrated in [47,48,51]. Additionally, we use this technique in the current paper.…”

Section: Literature Review and Introductionmentioning

confidence: 93%

“…Our approach is based on an analysis of the time-dependent spectral intensities (SDA-method) on both the absorption frequencies and the emission ones. Earlier, the SDA-method was successfully applied for the detection and identification of neutral and dangerous substances under real conditions [47][48][49][50][51][52][53][54], including the cases of very noisy THz signal and a sample with inhomogeneous surface. Therefore, we also follow this approach below.…”

Section: Literature Review and Introductionmentioning

confidence: 99%

Spurious Absorption Frequency Appearance Due to Frequency Conversion Processes in Pulsed THz TDS Problems

Trofimov

Wang

Qiu

et al. 2020

Sensors

Self Cite

View full text Add to dashboard Cite

The appearance of the spurious absorption frequencies caused by the frequency conversion process at the broadband THz pulse propagation in a medium is theoretically and experimentally discussed. The spurious absorption frequencies appear due to both the frequency doubling and generation of waves with sum or difference frequency. Such generation might occur because of the nonlinear response of a medium or its non-instantaneous response. This phenomenon is confirmed by the results of a few physical experiments provided with the THz CW signals and broadband THz pulses that are transmitted through the ordinary or dangerous substances. A high correlation between the time-dependent spectral intensities for the basic frequency and generated frequencies is demonstrated while using the computer simulation results. This feature of the frequency conversion might be used for the detection and identification of a substance.

show abstract

“…In References [40,41], we proposed using of the ICCs together with the SDA-method to achieve the detection with high probability. In References [42,43,44], the ICCs were applied for the substance detection and identification at long distance of about 3.5 meters under real conditions, which cause the highly noisy THz signal [45,46,47]. The essential limitations of the standard THz-TDS method also were demonstrated in [42,43,44,45,46,47].…”

Section: Introductionmentioning

confidence: 99%

A Possible Way for the Detection and Identification of Dangerous Substances in Ternary Mixtures Using THz Pulsed Spectroscopy

Trofimov

Varentsova

2019

Sensors

Self Cite

View full text Add to dashboard Cite

We discuss an effective tool for the detection and identification of substances in ternary mixtures with similar spectral properties using a broadband reflected THz signal. Nowadays, this is an urgent problem; its effective solution is still far off. Two ternary mixtures of the explosives (RDX+TNT+HMX and RDX+TNT+PETN) were used as the examples for demonstration of the efficiency of the method proposed. The identification is based on the pulsed THz spectroscopy. We follow the spectral intensities together with the use of integral correlation criteria. They use the spectral line dynamics of the THz pulse reflected from the substance under investigation and that of the standard THz signal from database. In order to increase the accuracy and reliability of the identification, we analyze the partial non-overlapping time intervals, containing the main pulse of the reflected THz signal and the sequential sub-pulses. The main pulse is shown to contain information about high absorption frequencies (ν > 2.6 THz) of the mixture components. In the sub-pulses, the absorption frequencies of the components are detected in the range of low (ν < 2.6 THz) and high (ν > 2.6 THz) frequencies. The opportunity of distinguishing the mixtures with similar spectral properties is also shown.

show abstract

Possibility of the detection and identification of substance at long distance using the noisy reflected THz pulse under real conditions

Cited by 6 publications

References 36 publications

High effective THz-TDS method for the detection and identification of substances in real conditions

High effective THz-TDS method for the detection and identification of substances in real conditions

Spurious Absorption Frequency Appearance Due to Frequency Conversion Processes in Pulsed THz TDS Problems

A Possible Way for the Detection and Identification of Dangerous Substances in Ternary Mixtures Using THz Pulsed Spectroscopy

Contact Info

Product

Resources

About