Cryogenic W-band Electron Spin Resonance Probehead with an Integral Cryogenic Low Noise Amplifier

Moamen Jbara, Oleg Zgadzai, Wolfgang Harneit, Aharon Blank

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish
JournalApplied Magnetic Resonance
DOIs
StateAccepted/In press - 2024

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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