Abstract: The Huygens construction is used to elucidate that the negative refraction phenomenon may occur in the common uniaxial crystals under the appropriate condition. The critical angle of incidence for occurrence negative refraction is calculated and the equation for numerically computing the negative refraction angle is obtained. This is beneficial for the students giving a right overall understanding while the left-handed materials and the negative refraction phenomenon are introduced in the teaching.

Key words: left-handed material, negative refraction, Huygens construction, uniaxial crystals