Temperature-dependent photo-elastic coefficient of silicon at 1550 nm

The associated paper presents a study on the temperature-dependent
photo-elastic coefficient in single-crystal silicon with (100) and (110)
orientations at a wavelength of 1550 nm. The measurement of the
photo-elastic coefficient was performed using a polarimetric scheme across
a wide temperature range from 5 K to 300 K. The experimental setup
employed high-sensitivity techniques and incorporated automatic beam path
correction, ensuring precise and accurate determination of the
coefficient’s values. The results show excellent agreement with previous
measurements at room temperature, specifically yielding a value of dn/dσ =
−2.463E-11 1/Pa for the (100) orientation. Interestingly, there is a
significant difference in photo-elasticity between the different crystal
orientations of approximately 50 %. The photo-elastic coefficient’s
absolute value increases by approximately 40 % with decreasing temperature
down to 5 K. These findings provide valuable insights into the
photo-elastic properties of silicon and its behavior under varying
mechanical stress, particularly relevant for optomechanical precision
experiments like cryogenic gravitational wave detectors and microscale
optomechanical quantum sensors.