Cryogenic Thermo-Optical Coefficient of SU-8 Measured Using a Racetrack Resonator at 850 nm
SU-8 is an emerging polymer material for integrated optical circuits that has demonstrated good structural properties in a cryogenic environment. In this article, we investigate the thermo-optical properties of SU-8 for a wavelength <inline-formula><math xmlns="http://www.w3.org/1998/M...
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2024-08-01
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| author | Salvador A. Medina-Rangel Nicola Maraviglia John O’Hara Artem S. Vorobev Simone Iadanza Emanuele Pelucchi Liam O’Faolain |
| author_facet | Salvador A. Medina-Rangel Nicola Maraviglia John O’Hara Artem S. Vorobev Simone Iadanza Emanuele Pelucchi Liam O’Faolain |
| author_sort | Salvador A. Medina-Rangel |
| collection | DOAJ |
| description | SU-8 is an emerging polymer material for integrated optical circuits that has demonstrated good structural properties in a cryogenic environment. In this article, we investigate the thermo-optical properties of SU-8 for a wavelength <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>λ</mi><mo>=</mo><mn>850</mn><mtext> </mtext><mi mathvariant="normal">n</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula>, from room temperature to cryogenic temperature down to 14 K. To measure the material properties, we designed and fabricated SU-8 racetrack resonators via electron beam lithography. While cooling the device in a closed-cycle cryostat, we measured the resonance spectrum as a function of the temperature from which we determined the temperature-induced variations of the group and effective indices of the waveguide. With the aid of waveguide eigenmode simulations, we used these data to derive the temperature dependence of the SU-8 refractive index <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>n</mi></mrow><mrow><mi>S</mi><mi>U</mi><mo>−</mo><mn>8</mn></mrow></msub><mfenced separators="|"><mrow><mi>T</mi></mrow></mfenced></mrow></semantics></math></inline-formula>. At room temperature (T~295 K), the thermo-optic coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mrow><msub><mrow><mi>d</mi><mi>n</mi></mrow><mrow><mi>S</mi><mi>U</mi><mo>−</mo><mn>8</mn></mrow></msub></mrow><mo>/</mo><mrow><mi>d</mi><mi>T</mi></mrow></mrow><mo>=</mo><mo>−</mo><mn>5.3</mn><mo>±</mo><msup><mrow><mn>0.2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup><mtext> </mtext><mi mathvariant="normal">K</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula>. At low temperature (T~14 K), <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mrow><msub><mrow><mi>d</mi><mi>n</mi></mrow><mrow><mi>S</mi><mi>U</mi><mo>−</mo><mn>8</mn></mrow></msub></mrow><mo>/</mo><mrow><mi>d</mi><mi>T</mi></mrow></mrow><mo>=</mo><mo>−</mo><mn>1.27</mn><mo>±</mo><msup><mrow><mn>0.05</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup><mtext> </mtext><mi mathvariant="normal">K</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula>. Our research shows the potential of SU-8 photonics in a cryogenic environment, suitable for the integration with quantum light sources emitting in the near infrared (NIR). |
| format | Article |
| id | doaj-art-de99d27f9e06490996afa90e68e30d0a |
| institution | OA Journals |
| issn | 2304-6732 |
| language | English |
| publishDate | 2024-08-01 |
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| spelling | doaj-art-de99d27f9e06490996afa90e68e30d0a2025-08-20T01:55:46ZengMDPI AGPhotonics2304-67322024-08-0111980010.3390/photonics11090800Cryogenic Thermo-Optical Coefficient of SU-8 Measured Using a Racetrack Resonator at 850 nmSalvador A. Medina-Rangel0Nicola Maraviglia1John O’Hara2Artem S. Vorobev3Simone Iadanza4Emanuele Pelucchi5Liam O’Faolain6Tyndall National Institute, University College Cork, Lee Maltings Complex Dyke Parade, T12 R5CP Cork, IrelandTyndall National Institute, University College Cork, Lee Maltings Complex Dyke Parade, T12 R5CP Cork, IrelandTyndall National Institute, University College Cork, Lee Maltings Complex Dyke Parade, T12 R5CP Cork, IrelandTyndall National Institute, University College Cork, Lee Maltings Complex Dyke Parade, T12 R5CP Cork, IrelandLaboratory of Nano and Quantum Technologies, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, SwitzerlandTyndall National Institute, University College Cork, Lee Maltings Complex Dyke Parade, T12 R5CP Cork, IrelandTyndall National Institute, University College Cork, Lee Maltings Complex Dyke Parade, T12 R5CP Cork, IrelandSU-8 is an emerging polymer material for integrated optical circuits that has demonstrated good structural properties in a cryogenic environment. In this article, we investigate the thermo-optical properties of SU-8 for a wavelength <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>λ</mi><mo>=</mo><mn>850</mn><mtext> </mtext><mi mathvariant="normal">n</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula>, from room temperature to cryogenic temperature down to 14 K. To measure the material properties, we designed and fabricated SU-8 racetrack resonators via electron beam lithography. While cooling the device in a closed-cycle cryostat, we measured the resonance spectrum as a function of the temperature from which we determined the temperature-induced variations of the group and effective indices of the waveguide. With the aid of waveguide eigenmode simulations, we used these data to derive the temperature dependence of the SU-8 refractive index <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>n</mi></mrow><mrow><mi>S</mi><mi>U</mi><mo>−</mo><mn>8</mn></mrow></msub><mfenced separators="|"><mrow><mi>T</mi></mrow></mfenced></mrow></semantics></math></inline-formula>. At room temperature (T~295 K), the thermo-optic coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mrow><msub><mrow><mi>d</mi><mi>n</mi></mrow><mrow><mi>S</mi><mi>U</mi><mo>−</mo><mn>8</mn></mrow></msub></mrow><mo>/</mo><mrow><mi>d</mi><mi>T</mi></mrow></mrow><mo>=</mo><mo>−</mo><mn>5.3</mn><mo>±</mo><msup><mrow><mn>0.2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup><mtext> </mtext><mi mathvariant="normal">K</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula>. At low temperature (T~14 K), <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mrow><msub><mrow><mi>d</mi><mi>n</mi></mrow><mrow><mi>S</mi><mi>U</mi><mo>−</mo><mn>8</mn></mrow></msub></mrow><mo>/</mo><mrow><mi>d</mi><mi>T</mi></mrow></mrow><mo>=</mo><mo>−</mo><mn>1.27</mn><mo>±</mo><msup><mrow><mn>0.05</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup><mtext> </mtext><mi mathvariant="normal">K</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula>. Our research shows the potential of SU-8 photonics in a cryogenic environment, suitable for the integration with quantum light sources emitting in the near infrared (NIR).https://www.mdpi.com/2304-6732/11/9/800SU-8thermo-optic coefficientpolymer waveguidecryogenicphotonic integrated circuitracetrack resonator |
| spellingShingle | Salvador A. Medina-Rangel Nicola Maraviglia John O’Hara Artem S. Vorobev Simone Iadanza Emanuele Pelucchi Liam O’Faolain Cryogenic Thermo-Optical Coefficient of SU-8 Measured Using a Racetrack Resonator at 850 nm Photonics SU-8 thermo-optic coefficient polymer waveguide cryogenic photonic integrated circuit racetrack resonator |
| title | Cryogenic Thermo-Optical Coefficient of SU-8 Measured Using a Racetrack Resonator at 850 nm |
| title_full | Cryogenic Thermo-Optical Coefficient of SU-8 Measured Using a Racetrack Resonator at 850 nm |
| title_fullStr | Cryogenic Thermo-Optical Coefficient of SU-8 Measured Using a Racetrack Resonator at 850 nm |
| title_full_unstemmed | Cryogenic Thermo-Optical Coefficient of SU-8 Measured Using a Racetrack Resonator at 850 nm |
| title_short | Cryogenic Thermo-Optical Coefficient of SU-8 Measured Using a Racetrack Resonator at 850 nm |
| title_sort | cryogenic thermo optical coefficient of su 8 measured using a racetrack resonator at 850 nm |
| topic | SU-8 thermo-optic coefficient polymer waveguide cryogenic photonic integrated circuit racetrack resonator |
| url | https://www.mdpi.com/2304-6732/11/9/800 |
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