Results found: 3

Number of results on page

Search results

Sort By:

Limit search:

Terahertz Frequency Domain Spectroscopy Identification System Based on Decision Trees

100%

Ryniec R., Zagrajek P., Pałka N.

Acta Physica Polonica A

2012

vol. 122

issue 5

891-895

The application of pattern recognition methodology within chemistry, biology and other science domains, especially in security systems is becoming more and more important. Many classification algorithms are available in literature but decision trees are the most commonly exploited because of their ease of implementation and understanding in comparison to other classification algorithms. Decision trees are powerful and popular tools for classification and prediction. In contrast to neural networks, decision trees represent rules, which can readily be expressed so that humans can understand them or even directly use in a database. In this paper we present an algorithm of construction of decision trees and a classification rule extraction based on a logical relationship between attributes and a generalized decision function. Moreover, correctness and efficiency of the algorithm was experimentally validated in a terahertz system, where spectra of explosives were measured in reflection configuration.

Transmission Spectra of Materials in the Terahertz Range Measured by a Hot Electron Bolometer-Based System

76%

Pałka N., Walczakowski M., Zagrajek P., Czerwiński A., Sypek M., Szustakowski M.

Acta Physica Polonica A

2013

vol. 124

issue 3

538-541

This paper presents an optical system for transmission spectral measurements in the terahertz range. The source of radiation is a tunable solid-state laser, which generates a narrow-band nanosecond pulses in the range 0.67-2.68 THz and based on optical parametric oscillator phenomenon. The signal is detected with a fast and sensitive hot electron bolometer. Principle of generation and detection of pulses as well as methodology of measuring spectral characteristics are presented. We compared the results obtained with the free-space setup, which is based on the optical parametric oscillator and hot electron bolometer, with a purged time domain spectroscopy system in the range of 0.7-2.2 THz.

An Influence of Silicon Substrate Parameters on a Responsivity of MOSFET-Based Terahertz Detectors

76%

Kucharski K., Zagrajek P., Tomaszewski D., Panas A., Głuszko G., Marczewski J., Kopyt P.

Acta Physica Polonica A

2016

vol. 130

issue 5

1193-1195

Silicon n-channel MOS transistors are a promising solution for sub-terahertz radiation detection. Their sensitivity is strongly related to the device construction. A type and thickness of the device substrate are key parameters affecting the responsivity, because the silicon substrate is a medium for the radiation propagation and the radiation energy loss, which degrades the detection efficiency. This work is aimed at analysis of the silicon substrate characteristics effect on operation of the MOSFETs as the terahertz radiation sensors. A manufacturing of the MOSFETs on three different substrate types including changing the substrate thickness is described in the paper. Next, the fabricated devices were exposed to THz radiation and their photoresponses were measured. It may be concluded that MOSFETs on silicon-on-insulator wafers with locally thinned substrates demonstrate the highest photoresponse. However, the experiments with the MOSFETs on high resisivity wafers give also promising results.

Refine search results

3 Acta Physica Polonica A

1 2016

1 2013

1 2012

3 Zagrajek P.

2 Pałka N.

1 Czerwiński A.

1 Głuszko G.

1 Kopyt P.

1 Kucharski K.

1 Marczewski J.

1 Panas A.

1 Ryniec R.

1 Sypek M.

1 Szustakowski M.

1 Tomaszewski D.

1 Walczakowski M.

Search results

Terahertz Frequency Domain Spectroscopy Identification System Based on Decision Trees

Transmission Spectra of Materials in the Terahertz Range Measured by a Hot Electron Bolometer-Based System

An Influence of Silicon Substrate Parameters on a Responsivity of MOSFET-Based Terahertz Detectors