Mr. Lun-Jun Liu Profile

Lun-Jun Liu

Graduate Student & Research Assistant at California Institute of Technology

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Author

Publications (13)

Proceedings Article | 17 August 2024 Presentation

The Terahertz Intensity Mapper: design, modeling, and characterization of the cryogenic receiver

Jianyang Fu, Shubh Agrawal, James Aguirre, Hrushi Athreya, Justin Bracks, Charles Bradford, Brockton Brendal, Nick Emerson, Jeffrey Filippini, Christopher Groppi, Steve Hailey-Dunsheath, Matthew Hollister, Reinier M. Janssen, Dylan Joralmon, Garrett Keating, Victor Gasho, Ryan Keenan, Mikolaj Kowalik, Lun-Jun Liu, Ian Lowe, Alex Manduca, Daniel Marrone, Philip Mauskopf, Evan Mayer, Rong Nie, Vesal Razavimaleki, Talia Saeid, Isaac Trumper, Joaquin Vieira, Jessica Zebrowski

Proceedings Volume PC13102, PC1310212 (2024) https://doi.org/10.1117/12.3019497

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Proceedings Article | 17 August 2024 Poster

Terahertz intensity mapper

Reinier M. Janssen, Shubh Agrawal, James Aguirre, Hrushi Athreya, Justin Bracks, Charles Bradford, Brockton Brendal, Bruce Bumble, Nick Emerson, Jeffrey Filippini, Jianyang Fu, Victor Gasho, Christopher Groppi, Steve Hailey-Dunsheath, Dylan Joralmon, Garrett Keating, Ryan Keenan, Mikolaj Kowalik, Lun-Jun Liu, Ian Lowe, Alex Manduca, Daniel Marrone, Philip Mauskopf, Evan Mayer, Rong Nie, Vesal Razavimaleki, Talia Saeid, Isaac Trumper, Joaquin Vieira, Jessica Zebrowski

Proceedings Volume PC13102, PC131021W (2024) https://doi.org/10.1117/12.3019189

Proceedings Article | 17 August 2024 Poster

Statistics on the optical performance of the kilopixel KID array for the terahertz intensity mapper (TIM) long wavelength spectrometer

Justin Bracks, Reinier M. Janssen, Shubh Agrawal, James Aguirre, Hrushi Athreya, Charles Bradford, Brockton Brendal, Bruce Bumble, Nick Emerson, Jeffrey Filippini, Jianyang Fu, Christopher Groppi, Steve Hailey-Dunsheath, Dylan Joralmon, Garrett Keating, Victor Gasho, Ryan Keenan, Mikolaj Kowalik, Lun-Jun Liu, Ian Lowe, Alex Manduca, Daniel Marrone, Philip Mauskopf, Evan Mayer, Vesal Razavimaleki, Talia Saeid, Isaac Trumper, Joaquin Vieira, Jessica Zebrowski, Rong Nie, Logan Foote, Elijah Kane

Proceedings Volume PC13102, PC131021J (2024) https://doi.org/10.1117/12.3020266

Proceedings Article | 17 August 2024 Presentation

The Terahertz Intensity Matter: science grade Kinetic Inductance Detector arrays

Lun-Jun Liu, Reinier M. Janssen, Bruce Bumble, Charles Bradford, Steve Hailey-Dunsheath, Shubh Agrawal, James Aguirre, Hrushi Athreya, Justin Bracks, Brockton Brendal, Jeffrey Filippini, Logan Foote, Jianyang Fu, Christopher Groppi, Dylan Joralmon, Elijah Kane, Garrett Keating, Ryan Keenan, Mikolaj Kowalik, Ian Lowe, Alex Manduca, Daniel Marrone, Philip Mauskopf, Evan Mayer, Rong Nie, Vesal Razavimaleki, Talia Saeid, Isaac Trumper, Joaquin Vieira, Jessica Zebrowski

Proceedings Volume PC13102, PC131020D (2024) https://doi.org/10.1117/12.3018118

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Proceedings Article | 16 August 2024 Poster + Paper

Development of an ultra-sensitive 210-micron array of KIDs for far-IR astronomy

Elijah Kane, Chris Albert, Nicholas Cothard, Steven Hailey-Dunsheath, Pierre Echternach, Logan Foote, Reinier Janssen, Henry (Rick) LeDuc, Lun-Jun (Simon) Liu, Hien Nguyen, Jason Glenn, Charles (Matt) Bradford, Jonas Zmuidzinas

Proceedings Volume 13102, 131021K (2024) https://doi.org/10.1117/12.3020346

KEYWORDS: Sensors, Black bodies, Resonators, Histograms, Inductance, Detector arrays, Design, Capacitors, Background noise, Tunable filters

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Proceedings Article | 16 August 2024 Presentation + Paper

Highly sensitive far-IR KIDs for PRIMA: optical characterization of a 25-micron array

Logan Foote, Chris Albert, Ritoban Basu Thakur, Nicholas Cothard, Peter Day, Steven Hailey-Dunsheath, Pierre Echternach, Byeong Ho Eom, Reinier Janssen, Elijah Kane, Henry Leduc, Lun-Jun Liu, Hien Nguyen, Jason Glenn, Charles Bradford, Jonas Zmuidzinas

Proceedings Volume 13102, 131020D (2024) https://doi.org/10.1117/12.3020228

KEYWORDS: Sensors, Black bodies, Spectroscopy, Modulation, Resonators, Detector arrays, Principal component analysis, Photon counting, Imaging spectroscopy

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Proceedings Article | 31 August 2022 Presentation + Paper

The terahertz intensity mapper: a balloon-borne imaging spectrometer for galaxy evolution

Daniel Marrone, James Aguirre, Justin Bracks, Charles Bradford, Brockton Brendal, Bruce Bumble, Anthony Corso, Mark Devlin, Nick Emerson, Jeffrey Filippini, Jianyang Fu, Victor Gasho, Christopher Groppi, Steve Hailey-Dunsheath, Jonathan Hoh, Matthew Hollister, Reinier M. Janssen, Dylan Joralmon, Ryan Keenan, Lun-Jun Liu, Ian Lowe, Philip Mauskopf, Evan Mayer, Rong Nie, Vesal Razavimaleki, Joseph Redford, Talia Saeid, Isaac Trumper, Joaquin Vieira

Proceedings Volume 12190, 1219008 (2022) https://doi.org/10.1117/12.2630644

KEYWORDS: Telescopes, Spectroscopy, Mirrors, Sensors, Cryogenics

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Proceedings Article | 31 August 2022 Poster + Paper

Design and testing of kinetic inductance detector package for the terahertz intensity mapper

L.-J. Liu, R. Janssen, C. Bradford, S. Hailey-Dunsheath, J. Filippini, J. Aguirre, J. Bracks, A. Corso, J. Fu, C. Groppi, J. Hoh, R. Keenan, I. Lowe, D. Marrone, P. Mauskopf, R. Nie, J. Redford, I. Trumper, J. Vieira

Proceedings Volume 12190, 121902F (2022) https://doi.org/10.1117/12.2629675

KEYWORDS: Galaxy evolution, Astronomy, Far infrared, Terahertz spectroscopy, Magnetism, Sensors, Aluminum, Semiconducting wafers, Stars, Magnetic sensors, Inductance, Prototyping, Galactic astronomy, Resonators

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The Terahertz Intensity Mapper (TIM) is designed to probe the star formation history in dust-obscured star-forming galaxies around the peak of cosmic star formation. This will be done via measurements of the redshifted 157.7 µm line of singly ionized carbon ([CII]). TIM employs two R~250 long-slit grating spectrometers covering 240 to 420 µm. Each is equipped with a focal plane unit containing four wafer-sized subarrays of horn-coupled aluminum kinetic inductance detectors (KIDs). We present the design and performance of a prototype focal plane assembly for one of TIM’s KID-based subarrays. The overall detector package must satisfy thermal and mechanical requirements, while maintaining high optical efficiency and a suitable electromagnetic environment for the KIDs. In particular, our design manages to strictly maintain a 50 µm air gap between the array and the horn block. The prototype detector housing in combination with the first flight-like quadrant were tested at 250 mK. A frequency scan using a vector network analyzer shows 823 resonance features, which represents ⪆90% yield, indicating a good performance of our TIM detector wafer and the whole focal plane unit. Initial measurements also showed that many resonances were affected by collisions and/or very shallow transmission dips as a result of a degraded internal quality factor. This is attributed to the presence of an external magnetic field during cooldown. We report on a study of magnetic field dependence of the quality factor of our quadrant array. We implemented a Helmholtz coil to vary the magnetic field at the detectors by (partially) nulling earth’s. Our investigation shows that the earth magnetic field can significantly affect our KIDs’ performance by degrading the quality factor by a factor of two to five, well below those expected from the operational temperature or optical loading. We find that we can sufficiently recover our detectors’ quality factor by tuning the current in the coils to generate a field that matches earth’s magnetic field in magnitude to within a few µT. We emphasize that it is impractical to fly a Helmholtz coil on TIM and dynamically “null” earth’s. Therefore, it is necessary to employ a properly designed magnetic shield enclosing the TIM focal plane unit. Based on the results presented in this paper, we set a shielding requirement of |B| ⪅3 µT.

Proceedings Article | 26 August 2022 Presentation

Kinetic inductance detectors for the Terahertz Intensity Mapper balloon mission: optical sensitivity and performance of kilopixel arrays.

Reinier M. J. Janssen, Rong Nie, Bruce Bumble, Lun-Jun Liu, Joseph Redford, Jeffrey Filippini, Charles Bradford, Steve Hailey-Dunsheath, James Aguirre, Justin Bracks, Anthony Corso, Jianyang Fu, Christopher Groppi, Jonathan Hoh, Ryan Keenan, Ian Lowe, Daniel Marrone, Philip Mauskopf, Isaac Trumper, Joaquin Vieira

Proceedings Volume PC12190, PC121900Q (2022) https://doi.org/10.1117/12.2630516

KEYWORDS: Sensors, Inductance, Spectrometers, Photodetectors, Staring arrays, Spectral resolution, Quasiparticles, Optical testing, Capacitors

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Proceedings Article | 13 December 2020 Poster + Presentation + Paper

Pre-flight optical test and calibration for the Cosmic Infrared Background ExpeRiment 2 (CIBER-2)

Kohji Takimoto, Seung-Cheol Bang, Priyadarshini Bangale, James Bock, Asantha Cooray, Kenta Danbayashi, Richard Feder, Masaki Furutani, Kevin Gates, Ryo Hashimoto, Viktor Hristov, Arisa Kida, Phillip Korngut, Alicia Lanz, Dae-Hee Lee, Lunjun Liu, Peter Mason, Toshio Matsumoto, Shuji Matsuura, Jodi-Ann Morgan, Chi Nguyen, Won-Kee Park, Dorin Patru, James Parkus, Shohta Sakai, Kei Sano, Hiroko Suzuki, Aoi Takahashi, Sohta Tatsu, Kohji Tsumura, Takehiko Wada, Shiang-Yu Wang, Yasuhiro Yamada, Michael Zemcov

Proceedings Volume 11443, 114435A (2020) https://doi.org/10.1117/12.2561917

KEYWORDS: Optical testing, Calibration, Infrared backgrounds, Optical calibration, Electron beam lithography, Galactic astronomy, Atmospheric optics, Rockets, Stars, Infrared radiation

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Proceedings Article | 13 December 2020 Poster + Presentation

Terahertz intensity mapper focal plane and array design

Reinier M. Janssen, Lunjun Liu, Rong Nie, Jianyang Fu, Isaac Trumper, Steve Hailey-Dunsheath, Charles Bradford, Jeffrey Filippini

Proceedings Volume 11453, 114531N (2020) https://doi.org/10.1117/12.2560705

KEYWORDS: Inductance, Detector arrays, Spectrometers, Aluminum, Absorption, Semiconducting wafers, Spectroscopy, Telescopes, Prototyping, Superconductors

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Proceedings Article | 6 July 2018 Paper

Development of data storage system and GSE for cosmic infrared background experiment 2 (CIBER-2)

Won-Kee Park, Seung-Chul Bang, John Battle, James Bock, Asantha Cooray, Kenta Danbayashi, Ambar DeSantiago, Viktor Hristov, Tomoya Kojima, Phillip Korngut, Alicia Lanz, Dae-Hee Lee, Lunjun Liu, Jared Loewenthal, Peter Mason, Toshio Matsumoto, Shuji Matsuura, Chi Nguyen, Ryo Ohta, Dorin Patru, Mark Peyer, Kei Sano, Aoi Takahashi, Kohji Takimoto, Kohji Tsumura, Takehiko Wada, Shiang-Yu Wang, Yasuhiro Yamada, Michael Zemcov

Proceedings Volume 10698, 1069849 (2018) https://doi.org/10.1117/12.2313184

KEYWORDS: Data acquisition, Electronics, Infrared backgrounds, Image sensors, Control systems, Rockets, Infrared detectors, Infrared astronomy, Software development

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Proceedings Article | 6 July 2018 Paper

Integration and instrument characterization of the cosmic infrared background experiment 2 (CIBER-2)

Chi Nguyen, Benjamin Stewart, Seung-Cheol Bang, James Bock, Asantha Cooray, Kenta Danbayashi, Ambar DeSantiago, Viktor Hristov, Tomoya Kojima, Phillip Korngut, Kevin Kruse, Alicia Lanz, Dae-Hee Lee, Lunjun Liu, Jared Loewenthal, Peter Mason, Toshio Matsumoto, Shuji Matsuura, Ryo Ohta, Christian Pape, Won-Kee Park, Dorin Patru, James Parkus, Kei Sano, Aoi Takahashi, Mark Peryer, Kohji Takimoto, Kohji Tsumura, Takehiko Wada, Shiang-Yu Wang, Yasuhiro Yamada, Michael Zemcov

Proceedings Volume 10698, 106984J (2018) https://doi.org/10.1117/12.2311595

KEYWORDS: Sensors, Rockets, Stars, Telescopes, Electronics, Cryogenics, Electron beam lithography, Data acquisition, Space telescopes

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Showing 5 of 13 publications

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