1. Extended Cauchy equations of congruent LiNbO_3 in the terahertz band and their applications
- Author
-
Yan-qing Lu, Wei Hu, Guang-hao Shao, Yun-chao Shi, and Shi-Jun Ge
- Subjects
Materials science ,Birefringence ,business.industry ,Infrared ,Terahertz radiation ,Lithium niobate ,Stacking ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,law.invention ,010309 optics ,Optical rectification ,chemistry.chemical_compound ,Optics ,chemistry ,Achromatic lens ,law ,0103 physical sciences ,Optoelectronics ,0210 nano-technology ,business ,Refractive index - Abstract
The refractive indices of ordinary and extraordinary waves (no and ne) of congruent LiNbO3 (CLN) in the terahertz (THz) band are measured at different temperatures. Extended Cauchy equations are proposed to describe the temperature- and frequency-dependent refractive indices. With less than 0.5% deviation, both no and ne can be obtained accurately. The values of no and ne are ~7 and ~5.4, respectively, which are much larger than those in the visible band. The extremely high birefringence (~1.6) may lead to some interesting applications of linear, electro-optic, and nonlinear optical effects of CLN. As an example, true zero-order THz waveplates (WPs) could be obtained with considerable low loss based on thin CLN wafers. The working frequency can be tuned by changing the environmental temperature. Moreover, wide bandwidth achromatic THz WPs were also achievable by stacking four CLN wafers together with precise orientation control.
- Published
- 2016
- Full Text
- View/download PDF