Anisotropy of two-photon absorption and free-carrier effect in nonpolar GaN

作者：Fang, Yu; Zhou, Feng; Yang, Junyi; Wu, Xingzhi; Xiao, Zhengguo; Li, Zhongguo; Song, Yinglin^*

来源：Applied Physics Letters, 2015, 106(13): 131903.

DOI：10.1063/1.4916829

• OPTICAL NONLINEARITIES
• ELECTRONIC-PROPERTIES
• CARBON NANOTUBES
• SILICON
• SEMICONDUCTORS
• FILMS
• GAAS
• INGAASP
• LIGHT
• INDEX

We reported a systematic study about the anisotropic optical nonlinearities in bulk m-plane and a-plane GaN crystals by Z-scan and pump-probe with phase object methods under picosecond at 532 nm. The two-photon absorption coefficient, which was measured as a function of polarization angle, exhibited oscillation curves with a period of pi/2, indicating a highly polarized optical third-order nonlinearity in both nonpolar GaN samples. Furthermore, free-carrier absorption revealed stronger hole-related absorption for E perpendicular to c than for E//c probe polarization. In contrast, free-carrier refraction was found almost isotropic due to electron-related refraction in the isotropic conduction bands.

• 出版日期2015-3-30
• 单位哈尔滨工业大学; 苏州大学