In this article, we present an experimental study of the polarization characteristics of the emission intensity from the surface of a material using terahertz (THz) passive measurements. We developed an experimental system and method to measure the intensity of a sample at several emission angles with vertical and horizontal polarization relative to the plane of the sample surface within a 5 K error in the brightness temperature. Emissions at 280 and 490 GHz wavebands were measured using subharmonic mixer receivers with Schottky barrier diodes operating at room temperature. We measured the intensity of radiation from a magnetic substance-loading material called MF110, which is used as a calibration hot load of THz radiometers because of its low reflectivity and light weight. Although the experimental conditions limited the range of the emission angle and temperatures of the sample and experimental system, it was confirmed that the polarization characteristics of the emission at each emission angle were in accordance with the Fresnel equations. Because the optical system in the experiment used a polarization rotator and a movable ellipsoidal mirror that enabled the receiver to remain stable, a highly sensitive system to measure sample emission was developed.
{"title":"Experimental Study of Polarization Characteristics of Terahertz Emission","authors":"Takayoshi Yamada;Makito Kobayashi;Yuki Uchiyama;Yutaka Hasegawa;Hiroyuki Maezawa;Hideaki Miyamoto;Yasuko Kasai","doi":"10.1109/TTHZ.2024.3496571","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3496571","url":null,"abstract":"In this article, we present an experimental study of the polarization characteristics of the emission intensity from the surface of a material using terahertz (THz) passive measurements. We developed an experimental system and method to measure the intensity of a sample at several emission angles with vertical and horizontal polarization relative to the plane of the sample surface within a 5 K error in the brightness temperature. Emissions at 280 and 490 GHz wavebands were measured using subharmonic mixer receivers with Schottky barrier diodes operating at room temperature. We measured the intensity of radiation from a magnetic substance-loading material called MF110, which is used as a calibration hot load of THz radiometers because of its low reflectivity and light weight. Although the experimental conditions limited the range of the emission angle and temperatures of the sample and experimental system, it was confirmed that the polarization characteristics of the emission at each emission angle were in accordance with the Fresnel equations. Because the optical system in the experiment used a polarization rotator and a movable ellipsoidal mirror that enabled the receiver to remain stable, a highly sensitive system to measure sample emission was developed.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 1","pages":"1-7"},"PeriodicalIF":3.9,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1109/TTHZ.2024.3492997
Theodore Reck;Jeffrey Hesler;Eric Bryerton
Correlating radiometers are presented at D-band (100–120 GHz) and G-band (160–185 GHz). The D-band system is a heterodyne receiver focused around the 118.75 GHz oxygen line and the G-band system is a direct-detection pseudocorrelating receiver focused around the 183.31 GHz water-vapor line. These systems are integrated into multiple waveguide blocks to facilitate troubleshooting and to enable different RF filters to be applied to the low noise amplifier (LNA)-based front ends. Discussion of the data-processing is presented for both systems. The D-band system has a noise temperature of 410 K at 120 GHz. The correlated output of this system increased the Allan time from 100 ms to 7 s. The G-band system has an average noise temperature of 780 K, with an increase in Allan time from 1 ms to 10 s.
{"title":"D- and G-Band Correlating Radiometers","authors":"Theodore Reck;Jeffrey Hesler;Eric Bryerton","doi":"10.1109/TTHZ.2024.3492997","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3492997","url":null,"abstract":"Correlating radiometers are presented at D-band (100–120 GHz) and G-band (160–185 GHz). The D-band system is a heterodyne receiver focused around the 118.75 GHz oxygen line and the G-band system is a direct-detection pseudocorrelating receiver focused around the 183.31 GHz water-vapor line. These systems are integrated into multiple waveguide blocks to facilitate troubleshooting and to enable different RF filters to be applied to the low noise amplifier (LNA)-based front ends. Discussion of the data-processing is presented for both systems. The D-band system has a noise temperature of 410 K at 120 GHz. The correlated output of this system increased the Allan time from 100 ms to 7 s. The G-band system has an average noise temperature of 780 K, with an increase in Allan time from 1 ms to 10 s.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 2","pages":"200-209"},"PeriodicalIF":3.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1109/TTHZ.2024.3492996
Cassandra N. Whitton;Daniel Lu;Adhitya B. Sriram;Philip D. Mauskopf;Christopher E. Groppi;Michael Marrs;Paul F. Goldsmith;Georgios C. Trichopoulos
There exist scientifically interesting molecular lines, such as the ground state transitions of water, that cannot be observed except from space. Observations of these lines can be made more cost-effective by lightweighting observation components, such as the primary optical aperture. This is particularly important for SmallSats and CubeSats which have highly limited weight budgets. Here, we present a flat lightweight metamaterial lens, which operates at 480 GHz, close to the 557 GHz ground state transition of ortho–H$_{2}$O. The lens is composed of alternating layers of spin-coated polyimide and patterned aluminum. The aluminum patterning was generated by optimization to a specific phase pattern. We have manufactured and tested the lens. The lens has an optical diameter of 124 mm. It weighs 3 grams and is less than 150 microns thick. It is also flexible. We have demonstrated using a near-field scan that the optical performance of the lens is nearly diffraction-limited. We have found the loss of the lens using radiometric techniques to be 2.5 dB. This loss is roughly 1.5 dB higher than expected, and we investigate possible reasons for this discrepancy.
{"title":"Design and Measurements of a 480 GHz Metamaterial Flat Lens","authors":"Cassandra N. Whitton;Daniel Lu;Adhitya B. Sriram;Philip D. Mauskopf;Christopher E. Groppi;Michael Marrs;Paul F. Goldsmith;Georgios C. Trichopoulos","doi":"10.1109/TTHZ.2024.3492996","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3492996","url":null,"abstract":"There exist scientifically interesting molecular lines, such as the ground state transitions of water, that cannot be observed except from space. Observations of these lines can be made more cost-effective by lightweighting observation components, such as the primary optical aperture. This is particularly important for SmallSats and CubeSats which have highly limited weight budgets. Here, we present a flat lightweight metamaterial lens, which operates at 480 GHz, close to the 557 GHz ground state transition of ortho–H<inline-formula><tex-math>$_{2}$</tex-math></inline-formula>O. The lens is composed of alternating layers of spin-coated polyimide and patterned aluminum. The aluminum patterning was generated by optimization to a specific phase pattern. We have manufactured and tested the lens. The lens has an optical diameter of 124 mm. It weighs 3 grams and is less than 150 microns thick. It is also flexible. We have demonstrated using a near-field scan that the optical performance of the lens is nearly diffraction-limited. We have found the loss of the lens using radiometric techniques to be 2.5 dB. This loss is roughly 1.5 dB higher than expected, and we investigate possible reasons for this discrepancy.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 2","pages":"218-227"},"PeriodicalIF":3.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1109/TTHZ.2024.3493001
Gonzalo García-Lozano;Guillermo Mercant;Marianela Fernández-Rodríguez;María Carmen Torquemada;Luis M. González;Tomás Belenguer;Alexander Cuadrado;Luis Miguel Sánchez-Brea;Javier Alda;Mahmoud Elshorbagy
The core of spectrometers for deep space exploration in the far-infrared spectral range is a diffraction grating optimized for a defined range of wavelengths. This contribution presents an in-depth analysis of the fabrication, morphological characterization, and spectral efficiency verification of this type of gratings operating in the THz range. Two different manufacturing techniques were used: the first one was laser ablation and microstructuring with a five-axis femtosecond laser system, and the second one was a traditional micromachining technique using milling tools. The gratings have a blazed geometry with saw-tooth profiles that enhances the efficiency of the diffracted order of interest, $m=1$ , at the TM polarization mode, and within a spectral range between 70 and 114 $mu$ m. The morphological features of the fabricated gratings were measured by confocal microscopy and analyzed using topographic parameters. The measured averaged profiles were used to compute the diffraction efficiency of the fabricated gratings and to compare the actual manufactured profiles against the experimental results. Our measurement setup fixes the wavelength of the illuminating source to six values between 60 and 120 $mu$ m (2.5 and 4.7 THz). At each of these spectral lines, we have scanned the angle of incidence between 20 $^circ$ and 75 $^circ$ . This angular range includes the nominal value of the angle of incidence, $theta _mathrm{inc}=57^circ$ . The experimental values of efficiency can be easily compared with those resulting from computation, where the efficiency is calculated for each one of the available wavelengths as a function of the angle of incidence. This approach has allowed us to validate the design and conclude that gratings fabricated using femtosecond laser ablation perform better than those obtained through micromachining processes. In any case, both manufacturing techniques generate gratings above the validation threshold for diffraction efficiency, $eta > 0.65$ .
{"title":"Experimental Analysis of the Spectral Reflectivity of Metallic Blazed Diffraction Gratings in the THz Range for Space Instrumentation","authors":"Gonzalo García-Lozano;Guillermo Mercant;Marianela Fernández-Rodríguez;María Carmen Torquemada;Luis M. González;Tomás Belenguer;Alexander Cuadrado;Luis Miguel Sánchez-Brea;Javier Alda;Mahmoud Elshorbagy","doi":"10.1109/TTHZ.2024.3493001","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3493001","url":null,"abstract":"The core of spectrometers for deep space exploration in the far-infrared spectral range is a diffraction grating optimized for a defined range of wavelengths. This contribution presents an in-depth analysis of the fabrication, morphological characterization, and spectral efficiency verification of this type of gratings operating in the THz range. Two different manufacturing techniques were used: the first one was laser ablation and microstructuring with a five-axis femtosecond laser system, and the second one was a traditional micromachining technique using milling tools. The gratings have a blazed geometry with saw-tooth profiles that enhances the efficiency of the diffracted order of interest, \u0000<inline-formula><tex-math>$m=1$</tex-math></inline-formula>\u0000, at the TM polarization mode, and within a spectral range between 70 and 114 \u0000<inline-formula><tex-math>$mu$</tex-math></inline-formula>\u0000m. The morphological features of the fabricated gratings were measured by confocal microscopy and analyzed using topographic parameters. The measured averaged profiles were used to compute the diffraction efficiency of the fabricated gratings and to compare the actual manufactured profiles against the experimental results. Our measurement setup fixes the wavelength of the illuminating source to six values between 60 and 120 \u0000<inline-formula><tex-math>$mu$</tex-math></inline-formula>\u0000m (2.5 and 4.7 THz). At each of these spectral lines, we have scanned the angle of incidence between 20\u0000<inline-formula><tex-math>$^circ$</tex-math></inline-formula>\u0000 and 75\u0000<inline-formula><tex-math>$^circ$</tex-math></inline-formula>\u0000. This angular range includes the nominal value of the angle of incidence, \u0000<inline-formula><tex-math>$theta _mathrm{inc}=57^circ$</tex-math></inline-formula>\u0000. The experimental values of efficiency can be easily compared with those resulting from computation, where the efficiency is calculated for each one of the available wavelengths as a function of the angle of incidence. This approach has allowed us to validate the design and conclude that gratings fabricated using femtosecond laser ablation perform better than those obtained through micromachining processes. In any case, both manufacturing techniques generate gratings above the validation threshold for diffraction efficiency, \u0000<inline-formula><tex-math>$eta > 0.65$</tex-math></inline-formula>\u0000.","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"15 1","pages":"8-16"},"PeriodicalIF":3.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10746638","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1109/TTHZ.2024.3492893
{"title":"2024 Index IEEE Transactions on Terahertz Science and Technology Vol. 14","authors":"","doi":"10.1109/TTHZ.2024.3492893","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3492893","url":null,"abstract":"","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 6","pages":"893-917"},"PeriodicalIF":3.9,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10746425","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1109/TTHZ.2024.3486590
{"title":"IEEE Women in Engineering","authors":"","doi":"10.1109/TTHZ.2024.3486590","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3486590","url":null,"abstract":"","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 6","pages":"890-890"},"PeriodicalIF":3.9,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10742499","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1109/TTHZ.2024.3486594
{"title":"IEEE Open Access Publishing","authors":"","doi":"10.1109/TTHZ.2024.3486594","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3486594","url":null,"abstract":"","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 6","pages":"891-891"},"PeriodicalIF":3.9,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10742497","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1109/TTHZ.2024.3486592
{"title":"TechRxiv: Share Your Preprint Research with the World!","authors":"","doi":"10.1109/TTHZ.2024.3486592","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3486592","url":null,"abstract":"","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 6","pages":"892-892"},"PeriodicalIF":3.9,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10742496","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1109/TTHZ.2024.3482636
{"title":"IEEE Transactions on Terahertz Science and Technology Publication Information","authors":"","doi":"10.1109/TTHZ.2024.3482636","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3482636","url":null,"abstract":"","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 6","pages":"C3-C3"},"PeriodicalIF":3.9,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10742495","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1109/TTHZ.2024.3482632
{"title":"IEEE Microwave Theory and Techniques Society Information","authors":"","doi":"10.1109/TTHZ.2024.3482632","DOIUrl":"https://doi.org/10.1109/TTHZ.2024.3482632","url":null,"abstract":"","PeriodicalId":13258,"journal":{"name":"IEEE Transactions on Terahertz Science and Technology","volume":"14 6","pages":"C2-C2"},"PeriodicalIF":3.9,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10742500","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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