TY - JOUR
T1 - Cryogenic W-band Electron Spin Resonance Probehead with an Integral Cryogenic Low Noise Amplifier
AU - Jbara, Moamen
AU - Zgadzai, Oleg
AU - Harneit, Wolfgang
AU - Blank, Aharon
N1 - Publisher Copyright:
© The Author(s) 2024.
PY - 2024
Y1 - 2024
N2 - The quest to enhance the sensitivity of electron spin resonance (ESR) is an ongoing challenge. One potential strategy involves increasing the frequency, for instance, moving from Q-band (approximately 35 GHz) to W-band (approximately 94 GHz). However, this shift typically results in higher transmission and switching losses, as well as increased noise in signal amplifiers. In this work, we address these shortcomings by employing a W-band probehead integrated with a cryogenic low-noise amplifier (LNA) and a microresonator. This configuration allows us to position the LNA close to the resonator, thereby amplifying the acquired ESR signal with minimal losses. Furthermore, when operated at cryogenic temperatures, the LNA exhibits unparalleled noise levels that are significantly lower than those of conventional room temperature LNAs. We detail the novel probehead design and provide some experimental results at room temperature as well as cryogenic temperatures for representative paramagnetic samples. We find, for example, that spin sensitivity of ~ 3 × 105 spins/√Hz is achieved for a sample of phosphorus doped 28Si, even for sub-optimal sample geometry with potential improvement to < 103 spins/√Hz in more optimal scenarios.
AB - The quest to enhance the sensitivity of electron spin resonance (ESR) is an ongoing challenge. One potential strategy involves increasing the frequency, for instance, moving from Q-band (approximately 35 GHz) to W-band (approximately 94 GHz). However, this shift typically results in higher transmission and switching losses, as well as increased noise in signal amplifiers. In this work, we address these shortcomings by employing a W-band probehead integrated with a cryogenic low-noise amplifier (LNA) and a microresonator. This configuration allows us to position the LNA close to the resonator, thereby amplifying the acquired ESR signal with minimal losses. Furthermore, when operated at cryogenic temperatures, the LNA exhibits unparalleled noise levels that are significantly lower than those of conventional room temperature LNAs. We detail the novel probehead design and provide some experimental results at room temperature as well as cryogenic temperatures for representative paramagnetic samples. We find, for example, that spin sensitivity of ~ 3 × 105 spins/√Hz is achieved for a sample of phosphorus doped 28Si, even for sub-optimal sample geometry with potential improvement to < 103 spins/√Hz in more optimal scenarios.
UR - http://www.scopus.com/inward/record.url?scp=85211360692&partnerID=8YFLogxK
U2 - 10.1007/s00723-024-01732-1
DO - 10.1007/s00723-024-01732-1
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AN - SCOPUS:85211360692
SN - 0937-9347
JO - Applied Magnetic Resonance
JF - Applied Magnetic Resonance
ER -