The weak strain induced by uniaxial strain device is calibrated by strain-induced second-harmonic generation (SISHG) from silicon (111) surface. Dependences of the strain-induced second-harmonic intensity on sample azimuth angle show that the strain leads to increase of SH intensity. The high consistency of the SH-measured strain and the applied strain indicates that weak strain can be accurately calibrated by SISHG. The small applied strain does not greatly affect the 3 m symmetry of silicon (111) surface, but enhances the SH intensity evidently. The bulk inversion symmetry of crystal silicon vanished under applying of uniaxial strain and this also has demonstrated by first-principles simulation. Furthermore, the theoretical relative variation of Si–Si bond length agrees exactly with the applied strain along  direction.
© 2013 Optical Society of America
Original Manuscript: December 6, 2012
Revised Manuscript: February 22, 2013
Manuscript Accepted: March 17, 2013
Published: April 12, 2013
Ji-Hong Zhao, Xian-Bin Li, Zhan-Guo Chen, Xing Meng, and Gang Jia, "Precise measurement of weak strain by second-harmonic generation from silicon (111) surface," J. Opt. Soc. Am. B 30, 1200-1204 (2013)