Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076169
V. Kulish, O. Lysenko, V. Savchenko
The physical analysis of two-stream superheterodyne free electron lasers (TSFELs) of the klystron type is accomplished. The multi-harmonic properties of signal, pumping, and space charge wave and the presence of a longitudinal focusing magnetic field in the system working bulk are accounted for. It is found that the main merits of the devices of the considered class are the following: compactness, extremely high level of amplification, the possibility for smooth changing working frequency, high level of input-output decoupling, capability of working at many signal-harmonics simultaneously (i.e., capability to amplify and forming signals with complex multi-harmonic spectrum, etc.).
{"title":"To the nonlinear multiharmonic theory of klystron type two-stream free electron laser","authors":"V. Kulish, O. Lysenko, V. Savchenko","doi":"10.1109/ICIMW.2002.1076169","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076169","url":null,"abstract":"The physical analysis of two-stream superheterodyne free electron lasers (TSFELs) of the klystron type is accomplished. The multi-harmonic properties of signal, pumping, and space charge wave and the presence of a longitudinal focusing magnetic field in the system working bulk are accounted for. It is found that the main merits of the devices of the considered class are the following: compactness, extremely high level of amplification, the possibility for smooth changing working frequency, high level of input-output decoupling, capability of working at many signal-harmonics simultaneously (i.e., capability to amplify and forming signals with complex multi-harmonic spectrum, etc.).","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74075625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076062
C. Guang, E. Oz, P. Muggli, R. Narang, C. Filip, S. Tochitsky, C. Clayton, K. Marsh, W. Mori, C. Joshi, R. Yoder, J. Rosenzweig, T. Katsouleas
Large amplitude electrostatic (ES) plasma waves are excited in plasma accelerators. By applying a static magnetic field transverse to the propagation direction of the wave, a fraction of the ES wave can be converted into electromagnetic radiation. This process can be described as Cerenkov radiation in a magnetized plasma, and can be used to produce short pulses of high power (i.e. GW) radiation in the THz wavelength range.
{"title":"A high power THz radiation source","authors":"C. Guang, E. Oz, P. Muggli, R. Narang, C. Filip, S. Tochitsky, C. Clayton, K. Marsh, W. Mori, C. Joshi, R. Yoder, J. Rosenzweig, T. Katsouleas","doi":"10.1109/ICIMW.2002.1076062","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076062","url":null,"abstract":"Large amplitude electrostatic (ES) plasma waves are excited in plasma accelerators. By applying a static magnetic field transverse to the propagation direction of the wave, a fraction of the ES wave can be converted into electromagnetic radiation. This process can be described as Cerenkov radiation in a magnetized plasma, and can be used to produce short pulses of high power (i.e. GW) radiation in the THz wavelength range.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78433021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076176
T. Nagashima, M. Hangyo
We have proposed and developed "terahertz ellipsometry" in which ellipsometry is applied to time-domain spectroscopy in the THz frequency region. In this paper, the complex optical constants of highly doped semiconductors obtained by terahertz ellipsometry are shown. In addition, the incident angle dependence of the measurement precision is discussed.
{"title":"Measurement of complex optical constant using terahertz ellipsometry","authors":"T. Nagashima, M. Hangyo","doi":"10.1109/ICIMW.2002.1076176","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076176","url":null,"abstract":"We have proposed and developed \"terahertz ellipsometry\" in which ellipsometry is applied to time-domain spectroscopy in the THz frequency region. In this paper, the complex optical constants of highly doped semiconductors obtained by terahertz ellipsometry are shown. In addition, the incident angle dependence of the measurement precision is discussed.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78450168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076087
Y. Roh, C. Domier, N. Luhmann
A multichannel ultrashort pulse reflectometry (USPR) system has been upgraded to enhance the performance of simultaneously measuring electron density profiles and fluctuations on the sustained spheromak physics experiment device (SSPX). In addition to the use of a high power frequency multiplier in the transmitter subsystem, the optimization of filter bandwidths in the receiver subsystem results in significant improvement of the dynamic range and signal-to-noise ratios of the USPR signals, thereby dramatically reducing the number of "lost" signals. Details of the upgraded USPR system are described together with USPR profile and fluctuation data.
{"title":"Upgraded ultrashort pulse reflectometry system on SSPX","authors":"Y. Roh, C. Domier, N. Luhmann","doi":"10.1109/ICIMW.2002.1076087","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076087","url":null,"abstract":"A multichannel ultrashort pulse reflectometry (USPR) system has been upgraded to enhance the performance of simultaneously measuring electron density profiles and fluctuations on the sustained spheromak physics experiment device (SSPX). In addition to the use of a high power frequency multiplier in the transmitter subsystem, the optimization of filter bandwidths in the receiver subsystem results in significant improvement of the dynamic range and signal-to-noise ratios of the USPR signals, thereby dramatically reducing the number of \"lost\" signals. Details of the upgraded USPR system are described together with USPR profile and fluctuation data.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77477081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076119
B. Schumann, R. Judaschke
A five-element in-line frequency doubler array at 300 GHz in a spatial power dividing/combining circuitry has been investigated. The waveguide doublers are realized with GaAs-Schottky-diodes and operate with 4% efficiency. Preliminary measurements of the system resulted in 8.35 mW output power. After a redesign, an overall efficiency of 2.5% (10 mW @ 300 GHz) is expected.
{"title":"A five-element 150/300 GHz frequency doubler","authors":"B. Schumann, R. Judaschke","doi":"10.1109/ICIMW.2002.1076119","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076119","url":null,"abstract":"A five-element in-line frequency doubler array at 300 GHz in a spatial power dividing/combining circuitry has been investigated. The waveguide doublers are realized with GaAs-Schottky-diodes and operate with 4% efficiency. Preliminary measurements of the system resulted in 8.35 mW output power. After a redesign, an overall efficiency of 2.5% (10 mW @ 300 GHz) is expected.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81264363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076138
F. Miyamaru, T. Nagashima, A. Hangyo
Two-dimensional metallic photonic crystals (2D-MPC) are composed of an equilateral array of hexagonally close packed circular waveguides. This type of 2D-MPC has been used as band-pass filters or frequency selective surfaces in the millimeter region. The band-pass characteristics are determined from several parameters, i.e. diameter of the circular holes (0.69 mm), spacing between the centers of them (1.13 mm), and length of the circular waveguides (0.5 mm). The air-filling fraction of this 2D-MPC is 34%. We measured the transmission spectra of the 2D-MPC in the frequency range from 0.1 to 1 THz using the THz time domain spectroscopy.
{"title":"Transmission characteristics of finite-size, two-dimensional metallic photonic crystals studied by THz time domain spectroscopy","authors":"F. Miyamaru, T. Nagashima, A. Hangyo","doi":"10.1109/ICIMW.2002.1076138","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076138","url":null,"abstract":"Two-dimensional metallic photonic crystals (2D-MPC) are composed of an equilateral array of hexagonally close packed circular waveguides. This type of 2D-MPC has been used as band-pass filters or frequency selective surfaces in the millimeter region. The band-pass characteristics are determined from several parameters, i.e. diameter of the circular holes (0.69 mm), spacing between the centers of them (1.13 mm), and length of the circular waveguides (0.5 mm). The air-filling fraction of this 2D-MPC is 34%. We measured the transmission spectra of the 2D-MPC in the frequency range from 0.1 to 1 THz using the THz time domain spectroscopy.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84269418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076187
B. Yefimov, K. Ilyenko, T. Yatsenko
We report electromagnetic noise radiation produced by a curvilinear electron flow with the mean electron velocities of 0.1 - 0.3 c in the Motz undulator of the period 10 mm, the amplitude of the static transversal sinusoidal undulator field 0.6 kOe and the uniform longitudinal guide magnetic field 0 - 10 kOe. The input electron beam with the diameter of 0.5 mm was created by an electron gun with a shield cathode and possessed the density of current of up to 10 A/cm/sup 2/. A resonant enhancement (by 10 - 50 times) of the spontaneous radiation was theoretically predicted and observed for first harmonics of the base frequency. The phenomenon is caused by the presence of the guide magnetic field and can be efficiently utilized in FEL devices with electron energies of up to 350 keV.
{"title":"Resonance noise radiation of a non-relativistic FEL oscillator in the presence of guide magnetic field","authors":"B. Yefimov, K. Ilyenko, T. Yatsenko","doi":"10.1109/ICIMW.2002.1076187","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076187","url":null,"abstract":"We report electromagnetic noise radiation produced by a curvilinear electron flow with the mean electron velocities of 0.1 - 0.3 c in the Motz undulator of the period 10 mm, the amplitude of the static transversal sinusoidal undulator field 0.6 kOe and the uniform longitudinal guide magnetic field 0 - 10 kOe. The input electron beam with the diameter of 0.5 mm was created by an electron gun with a shield cathode and possessed the density of current of up to 10 A/cm/sup 2/. A resonant enhancement (by 10 - 50 times) of the spontaneous radiation was theoretically predicted and observed for first harmonics of the base frequency. The phenomenon is caused by the presence of the guide magnetic field and can be efficiently utilized in FEL devices with electron energies of up to 350 keV.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84499193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076211
S. K. Datta, E. V. Jayashree, S. Veena, L. Kumar
A simple scheme of broadbanding a helical slow-wave structure is proposed using helix support structure made of composite chiral dielectric material. The dispersion relation of the slow-wave structure obtained by sheath-helix field analysis and the dispersion behavior of a typical structure analyzed. It was seen that negative dispersion characteristics, required for broadband operation of the device, could be achieved by merely controlling the chirality parameter alone.
{"title":"Broadbanding of a helical slow-wave structure using chiral dielectric loading","authors":"S. K. Datta, E. V. Jayashree, S. Veena, L. Kumar","doi":"10.1109/ICIMW.2002.1076211","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076211","url":null,"abstract":"A simple scheme of broadbanding a helical slow-wave structure is proposed using helix support structure made of composite chiral dielectric material. The dispersion relation of the slow-wave structure obtained by sheath-helix field analysis and the dispersion behavior of a typical structure analyzed. It was seen that negative dispersion characteristics, required for broadband operation of the device, could be achieved by merely controlling the chirality parameter alone.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85889653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076116
M. Tani, S. Kono, M. Nakajima, M. Iida, K. Sakai
We report the generation and detection of ultrabroadband THz radiation using photoconductive antennas as the emitter and the detector. The photoconductive antenna showed a detection bandwidth as broad as the electro-optic sampling detectors. On the other hand, the photoconductive emitter showed a spectral bandwidth much narrower than that of the electro-optic emitters. We discuss the bandwidth properties of the photoconductive emitters and detectors in comparison with their electro-optic counterparts.
{"title":"Generation and detection of ultrabroadband Terahertz radiation with photoconductive antennas","authors":"M. Tani, S. Kono, M. Nakajima, M. Iida, K. Sakai","doi":"10.1109/ICIMW.2002.1076116","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076116","url":null,"abstract":"We report the generation and detection of ultrabroadband THz radiation using photoconductive antennas as the emitter and the detector. The photoconductive antenna showed a detection bandwidth as broad as the electro-optic sampling detectors. On the other hand, the photoconductive emitter showed a spectral bandwidth much narrower than that of the electro-optic emitters. We discuss the bandwidth properties of the photoconductive emitters and detectors in comparison with their electro-optic counterparts.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76834383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-12-16DOI: 10.1109/ICIMW.2002.1076162
Y. Pirogov
The paper presents results of radio imaging investigations at Moscow University. Some facilities in 8-mm and 3-mm ranges were developed to demonstrate the effectiveness of some super-resolution methods. In the 8-mm range, the super-resolution factor had a value of about 10. After processing in the 3-mm case, the resolution of the passive radio vision facility with moderate size of antenna was practically the same as in optics.
{"title":"Passive radio imaging in 8-mm and 3-mm ranges","authors":"Y. Pirogov","doi":"10.1109/ICIMW.2002.1076162","DOIUrl":"https://doi.org/10.1109/ICIMW.2002.1076162","url":null,"abstract":"The paper presents results of radio imaging investigations at Moscow University. Some facilities in 8-mm and 3-mm ranges were developed to demonstrate the effectiveness of some super-resolution methods. In the 8-mm range, the super-resolution factor had a value of about 10. After processing in the 3-mm case, the resolution of the passive radio vision facility with moderate size of antenna was practically the same as in optics.","PeriodicalId":23431,"journal":{"name":"Twenty Seventh International Conference on Infrared and Millimeter Waves","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76894701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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