Pub Date : 2021-08-29DOI: 10.1109/IRMMW-THz50926.2021.9567188
Hanyu Zhao, Huajie Liang, S. Liang, S. Gong, Yaxin Zhang
This paper presents a single-segment phase shifter based on GaAs diode at 220 GHz. In this structure, a phase-shifting unit is inserted into the center of the rectangular waveguide surface. The state of the GaAs diode on the phase shifting unit is controlled by an external voltage. Then the equivalent impedance of the load branch is changed, resulting in phase shift. Finally, within 217.5GHz-225.5GHz, a continuous phase shift of 180° can be achieved, the insertion loss is less than 8.2dB and the phase shift difference between each state is about 22.5°.
{"title":"A terahertz 180° continuous phase shifter based on GaAs diode","authors":"Hanyu Zhao, Huajie Liang, S. Liang, S. Gong, Yaxin Zhang","doi":"10.1109/IRMMW-THz50926.2021.9567188","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9567188","url":null,"abstract":"This paper presents a single-segment phase shifter based on GaAs diode at 220 GHz. In this structure, a phase-shifting unit is inserted into the center of the rectangular waveguide surface. The state of the GaAs diode on the phase shifting unit is controlled by an external voltage. Then the equivalent impedance of the load branch is changed, resulting in phase shift. Finally, within 217.5GHz-225.5GHz, a continuous phase shift of 180° can be achieved, the insertion loss is less than 8.2dB and the phase shift difference between each state is about 22.5°.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"439 1-3 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77886937","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 : 2021-08-29DOI: 10.1109/IRMMW-THz50926.2021.9567634
N. Ginzburg, V. Zaslavsky, A. Malkin, A. Sergeev, I. Zotova, G. Boltachev, K. Sharypov, S. Shunailov, M. R. Ul’Masculov, M. Yalandin
We present the results of experiments on generation of sub-nanosecond 90-GHz superradiant (SR) pulses with a record peak power of ~150 MW. Such pulses are produced based on excitation of a surface wave in an oversized waveguide with 2D (double-periodical) corrugation. In such a structure, azimuthally propagating wave fluxes synchronize radiation from different azimuthal segments of a tubular electron bunch with a diameter greatly exceeding the wavelength. The implemented approach opens up the prospect of a radical increase in the total electron current and the peak power of SR pulses while maintaining azimuthal coherence of radiation. The results of experiments are in line with the theoretical predictions within the frame of the quasi-optical model and direct PIC simulations.
{"title":"Generation of 150 MW/0.7 ns W-Band Superradiant Pulses in a Strongly Oversized 2D Periodical Surface-Wave Structure","authors":"N. Ginzburg, V. Zaslavsky, A. Malkin, A. Sergeev, I. Zotova, G. Boltachev, K. Sharypov, S. Shunailov, M. R. Ul’Masculov, M. Yalandin","doi":"10.1109/IRMMW-THz50926.2021.9567634","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9567634","url":null,"abstract":"We present the results of experiments on generation of sub-nanosecond 90-GHz superradiant (SR) pulses with a record peak power of ~150 MW. Such pulses are produced based on excitation of a surface wave in an oversized waveguide with 2D (double-periodical) corrugation. In such a structure, azimuthally propagating wave fluxes synchronize radiation from different azimuthal segments of a tubular electron bunch with a diameter greatly exceeding the wavelength. The implemented approach opens up the prospect of a radical increase in the total electron current and the peak power of SR pulses while maintaining azimuthal coherence of radiation. The results of experiments are in line with the theoretical predictions within the frame of the quasi-optical model and direct PIC simulations.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"33 1 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79784424","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 : 2021-08-29DOI: 10.1109/IRMMW-THz50926.2021.9567576
M. Alonso-delPino, S. Bosma, C. Jung-Kubiak, G. Chattopadhyay, N. Llombart
In this paper, we will present a novel quasi-optical power distribution technique that will allow achieving an efficient multi-pixel LO power distribution for submillimeter-wave instruments. This method can distribute the power from one antenna to a multi-pixel lens array in a hexagonal configuration with a power coupling efficiency of nearly 60%. We will present a prototype based on a transmit array of 7 pixels at WR1.5.
{"title":"Broadband Power Distribution using Multi-Mode Leaky-Wave Lens Antennas at Submillimeter Wavelengths","authors":"M. Alonso-delPino, S. Bosma, C. Jung-Kubiak, G. Chattopadhyay, N. Llombart","doi":"10.1109/IRMMW-THz50926.2021.9567576","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9567576","url":null,"abstract":"In this paper, we will present a novel quasi-optical power distribution technique that will allow achieving an efficient multi-pixel LO power distribution for submillimeter-wave instruments. This method can distribute the power from one antenna to a multi-pixel lens array in a hexagonal configuration with a power coupling efficiency of nearly 60%. We will present a prototype based on a transmit array of 7 pixels at WR1.5.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"84 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79804834","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}
In this paper, a transmission-type power equalizer based on metallic rectangular waveguide with good tunability, high power handling capacity and simple structure for a Ka-band gyrotron travelling wave tube (gyro-TWT) is proposed. To verify the feasibility of the equalizer, a prototype operated at 32-35.5 GHz is fabricated and measured. The vector network analyzer (VNA) measurement results were in good agreement with the CST simulations.
{"title":"Design and Measurement of a Transmission-Type Waveguide Power Equalizer for a Ka-Band Gyro-TWT","authors":"Xiyuan Quan, Guo Liu, Wei Jiang, Jianxun Wang, Zewei Wu, Youlei Pu, Yong Luo","doi":"10.1109/IRMMW-THz50926.2021.9566858","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9566858","url":null,"abstract":"In this paper, a transmission-type power equalizer based on metallic rectangular waveguide with good tunability, high power handling capacity and simple structure for a Ka-band gyrotron travelling wave tube (gyro-TWT) is proposed. To verify the feasibility of the equalizer, a prototype operated at 32-35.5 GHz is fabricated and measured. The vector network analyzer (VNA) measurement results were in good agreement with the CST simulations.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"30 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79156918","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 : 2021-08-29DOI: 10.1109/IRMMW-THz50926.2021.9567591
Ariane De Vroede, P. Reynaert
The frequency scalability of self-mixing transistors with zero drain bias for THz power detection is demonstrated. Measurements of individual patch-coupled detectors tuned at 0.56 and 1.06 THz indicate no sensitivity degradation when moving towards higher frequencies.
{"title":"Performance Comparison of Self-Mixing Transistors at 0.56 and 1.06 THz in 65nm CMOS","authors":"Ariane De Vroede, P. Reynaert","doi":"10.1109/IRMMW-THz50926.2021.9567591","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9567591","url":null,"abstract":"The frequency scalability of self-mixing transistors with zero drain bias for THz power detection is demonstrated. Measurements of individual patch-coupled detectors tuned at 0.56 and 1.06 THz indicate no sensitivity degradation when moving towards higher frequencies.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"19 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79392370","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 : 2021-08-29DOI: 10.1109/IRMMW-THz50926.2021.9567255
A.A. Paraipan, A. M. Conte, M. Missori
Terahertz time-domain spectroscopy (THz-TDS) is a powerful tool for probing collective molecular vibrational modes of biomolecules. In this study, we used THz-TDS to investigate the low-energy vibrational modes of a group of organic molecules belonging to saccharides (or carbohydrate) in their solid state. Ab-initio simulations based on density functional theory (DFT) were carried out by employing a state-of-the-art method for the calculation of the weak intermolecular forces driving the collective motion of organic molecules. This approach allowed us to identify and analyze the low-energy vibrations finding their percentage contributions of intermolecular and intramolecular motion of the optical phonons.
{"title":"Experimental and theoretical THz spectroscopy of solid saccharides","authors":"A.A. Paraipan, A. M. Conte, M. Missori","doi":"10.1109/IRMMW-THz50926.2021.9567255","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9567255","url":null,"abstract":"Terahertz time-domain spectroscopy (THz-TDS) is a powerful tool for probing collective molecular vibrational modes of biomolecules. In this study, we used THz-TDS to investigate the low-energy vibrational modes of a group of organic molecules belonging to saccharides (or carbohydrate) in their solid state. Ab-initio simulations based on density functional theory (DFT) were carried out by employing a state-of-the-art method for the calculation of the weak intermolecular forces driving the collective motion of organic molecules. This approach allowed us to identify and analyze the low-energy vibrations finding their percentage contributions of intermolecular and intramolecular motion of the optical phonons.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"11 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84293084","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 : 2021-08-29DOI: 10.1109/IRMMW-THz50926.2021.9566859
J. Li, R. Rana, L. Zhu, C. Liu, H. Schneider, A. Pashkin
We have studied the THz generation in DSTMS using a quasi-3D model that takes into account high-order nonlinear effects beyond the χ(2) nonlinearity. The nonlinear refractive index (Kerr effect) and three-photon absorption (3PA) coefficients for the wavelength of 1.4 μm utilized in the model were determined by the Z-scan method. The simulation results are in good agreement with the experimentally measured THz and near-infrared spectra, confirming the validity of the proposed model. Our analysis shows that the 3PA process mainly limits THz generation in DSTMS at high pump fluences. The cascaded optical rectification further decreases THz conversion efficiency due to the spectral broadening of the excitation pulse.
{"title":"THz conversion efficiency in DSTMS limited by high-order nonlinearities","authors":"J. Li, R. Rana, L. Zhu, C. Liu, H. Schneider, A. Pashkin","doi":"10.1109/IRMMW-THz50926.2021.9566859","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9566859","url":null,"abstract":"We have studied the THz generation in DSTMS using a quasi-3D model that takes into account high-order nonlinear effects beyond the χ(2) nonlinearity. The nonlinear refractive index (Kerr effect) and three-photon absorption (3PA) coefficients for the wavelength of 1.4 μm utilized in the model were determined by the Z-scan method. The simulation results are in good agreement with the experimentally measured THz and near-infrared spectra, confirming the validity of the proposed model. Our analysis shows that the 3PA process mainly limits THz generation in DSTMS at high pump fluences. The cascaded optical rectification further decreases THz conversion efficiency due to the spectral broadening of the excitation pulse.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"15 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85040909","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 : 2021-08-29DOI: 10.1109/IRMMW-THz50926.2021.9567395
S. Roh, Samuel Pinnock, Jens Jakschik, A. Pronin, M. Dressel
A THz vortex beam describes light with a larger than ordinary total angular momentum. Increased total angular momentum modifies the optical selection rules, opening a new territory of material research. We discuss the basic concept of vortex beams and a possible approach for future THz studies. The experiments on Landau level transitions will be given as an example.
{"title":"THz Vortex Light and Landau Level Transitions in Topological Semimetals","authors":"S. Roh, Samuel Pinnock, Jens Jakschik, A. Pronin, M. Dressel","doi":"10.1109/IRMMW-THz50926.2021.9567395","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9567395","url":null,"abstract":"A THz vortex beam describes light with a larger than ordinary total angular momentum. Increased total angular momentum modifies the optical selection rules, opening a new territory of material research. We discuss the basic concept of vortex beams and a possible approach for future THz studies. The experiments on Landau level transitions will be given as an example.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"117 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85614915","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 : 2021-08-29DOI: 10.1109/IRMMW-THz50926.2021.9567088
Yulian He, Yuansheng Wang, Q. Wen
With a surface-passivated GaAs, a performance-enhanced, ultrafast, all-optical spatial terahertz modulator was realized. The lower surface recombination rate and longer carrier lifetime induced by passivation render passivated-GaAs superior to pure-GaAs in modulation depth (MD) at a little sacrifice of response rate, eliminating its dependence on intensive laser. At low photodoping levels, the maximum of 1.6-times enhancement in MD was achieved. When the power increased to 60 mW, comparable MD of 94% to that in Si-based one at equivalent photodoping, and simultaneously ultrafast response of 69 MHz which is much faster than 100-kHz level by Si-based, was obtained. This performance-enhanced, ultrafast modulator is highly desired in actual situations and offers a viable avenue to breaking the compromise between MD and speed.
{"title":"Ultrafast All-Optical Terahertz Modulation with Sulfur-Passivated GaAs","authors":"Yulian He, Yuansheng Wang, Q. Wen","doi":"10.1109/IRMMW-THz50926.2021.9567088","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9567088","url":null,"abstract":"With a surface-passivated GaAs, a performance-enhanced, ultrafast, all-optical spatial terahertz modulator was realized. The lower surface recombination rate and longer carrier lifetime induced by passivation render passivated-GaAs superior to pure-GaAs in modulation depth (MD) at a little sacrifice of response rate, eliminating its dependence on intensive laser. At low photodoping levels, the maximum of 1.6-times enhancement in MD was achieved. When the power increased to 60 mW, comparable MD of 94% to that in Si-based one at equivalent photodoping, and simultaneously ultrafast response of 69 MHz which is much faster than 100-kHz level by Si-based, was obtained. This performance-enhanced, ultrafast modulator is highly desired in actual situations and offers a viable avenue to breaking the compromise between MD and speed.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"130 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85759994","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 : 2021-08-29DOI: 10.1109/IRMMW-THz50926.2021.9567318
M. Yu, W. Xu, J. Shi, G. Wu, H. Wang, P. Wu
High temperature superconducting (HTS) Josephson junction (JJ) mixers are attractive candidates in receivers for terahertz (THz) communication due to their high sensitivity, wide bandwidth, low local oscillator (LO) power requirement and high harmonic numbers. The required LO frequencies and the cost can be greatly reduced when harmonic signals can be detected at high orders (more than 100). In this paper, up to 114th harmonic mixings is presented in a HTS bicrystal YBa2Cu3O7-δ (YBCO) JJ harmonic mixer coupled with a bowtie loaded meander antenna at 0.21 THz. HTS JJs will be promising high-order harmonic mixers for THz practical applications on reception or detection at THz bands.
{"title":"Terahertz harmonic mixer based on HTS Josephson junction","authors":"M. Yu, W. Xu, J. Shi, G. Wu, H. Wang, P. Wu","doi":"10.1109/IRMMW-THz50926.2021.9567318","DOIUrl":"https://doi.org/10.1109/IRMMW-THz50926.2021.9567318","url":null,"abstract":"High temperature superconducting (HTS) Josephson junction (JJ) mixers are attractive candidates in receivers for terahertz (THz) communication due to their high sensitivity, wide bandwidth, low local oscillator (LO) power requirement and high harmonic numbers. The required LO frequencies and the cost can be greatly reduced when harmonic signals can be detected at high orders (more than 100). In this paper, up to 114th harmonic mixings is presented in a HTS bicrystal YBa2Cu3O7-δ (YBCO) JJ harmonic mixer coupled with a bowtie loaded meander antenna at 0.21 THz. HTS JJs will be promising high-order harmonic mixers for THz practical applications on reception or detection at THz bands.","PeriodicalId":6852,"journal":{"name":"2021 46th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)","volume":"1 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2021-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85880082","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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