Inversion of the Sign of Birefringence and its Application in Thermometry

Abstract

Based on interference of polarized light the application of optical birefringence sign-inversion effect in biaxial crystals for temperature reference points and measurements is described. The reference point is determined through the shape of the conoscopic pattern or a minimum of the corresponding photocurrent. The known crystals cover the range from ∼ 20 K up to 1000 K. The sensitivity of the method is estimated to be 0.1–0.001 K. It is protected from electromagnetic interference. Parameters of the sensor are stable with temperature cycling, and the sensor has a built-in temperature reference point.

Keywords:

• Inversion of birefringence sign
• temperature reference points
• thermometry

PACS:

• 78.20.Nv+07.20.Dt.
• 42.81.Gs
• 42.81.Pa