An FBG Optical Approach to Thermal Expansion Measurements under Hydrostatic Pressure

Priscila F S Rosa; Sean M Thomas; Fedor F Balakirev; Jon Betts; Soonbeom Seo; Eric D Bauer; Joe D Thompson; Marcelo Jaime

doi:10.3390/s17112543

An FBG Optical Approach to Thermal Expansion Measurements under Hydrostatic Pressure

Sensors (Basel). 2017 Nov 4;17(11):2543. doi: 10.3390/s17112543.

Authors

Priscila F S Rosa¹, Sean M Thomas², Fedor F Balakirev³, Jon Betts⁴, Soonbeom Seo⁵, Eric D Bauer⁶, Joe D Thompson⁷, Marcelo Jaime^{8

9}

Affiliations

¹ Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA. pfsrosa@lanl.gov.
² Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA. smthomas@lanl.gov.
³ National High Magnetic Field Laboratory, Los Alamos National Laboratory, MS E536, Los Alamos, NM 87545, USA. fedor@lanl.gov.
⁴ National High Magnetic Field Laboratory, Los Alamos National Laboratory, MS E536, Los Alamos, NM 87545, USA. jbbetts@lanl.gov.
⁵ Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA. soonbeom@lanl.gov.
⁶ Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA. edbauer@lanl.gov.
⁷ Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA. jdt@lanl.gov.
⁸ National High Magnetic Field Laboratory, Los Alamos National Laboratory, MS E536, Los Alamos, NM 87545, USA. mjaime@lanl.gov.
⁹ Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. mjaime@lanl.gov.

Abstract

We report on an optical technique for measuring thermal expansion and magnetostriction at cryogenic temperatures and under applied hydrostatic pressures of 2.0 GPa. Optical fiber Bragg gratings inside a clamp-type pressure chamber are used to measure the strain in a millimeter-sized sample of CeRhIn₅. We describe the simultaneous measurement of two Bragg gratings in a single optical fiber using an optical sensing instrument capable of resolving changes in length [dL/L = (L- L₀)/L₀] on the order of 10^-7. Our results demonstrate the possibility of performing high-resolution thermal expansion measurements under hydrostatic pressure, a capability previously hindered by the small working volumes typical of pressure cells.

Keywords: hydrostatic pressure; optical fiber Bragg grating; quantum criticality.