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Tests of Sapphire Crystals Produced with Different Growth Processes for Ultra-stable Microwave Oscillators

Instrumentation and Detectors 2016-01-20 v1

Abstract

We present the characterization of 8-12 GHz whispering gallery mode resonators machined in high-quality sapphire crystals elaborated with different growth techniques. These microwave resonators are intended to constitute the reference frequency of ultra-stable Cryogenic Sapphire Oscillators. We conducted systematic tests near 4 K on these crystals to determine the unloaded Q-factor and the turnover temperature for whispering gallery modes in the 8-12 GHz frequency range. These characterizations show that high quality sapphire crystals elaborated with the Heat Exchange or the Kyropoulos growth technique are both suitable to meet a fractional frequency stability better than 1x10-15 for 1 s to 10.000 s integration times.

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Cite

@article{arxiv.1504.02711,
  title  = {Tests of Sapphire Crystals Produced with Different Growth Processes for Ultra-stable Microwave Oscillators},
  author = {Vincent Giordano and Christophe Fluhr and Serge Grop and Benoit Dubois},
  journal= {arXiv preprint arXiv:1504.02711},
  year   = {2016}
}

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