变折射率组合三角棱镜产生无衍射线结构光

Step Refractive Index Combined Triangular-Section Prism Generating Non-Diffracting Linear Structured Beam

提出一种可产生大焦深无衍射线结构光的新型光学元件——变折射率组合三角棱镜,由正、负等腰三角棱镜胶合在一起设计而成,其变换光束特性与单个正等腰三角棱镜相同,等效折射率由正、负等腰三角棱镜折射率之差决定,因此可通过两个折射率接近的正、负等腰三角棱镜组合得到一个更加接近1的等效折射率,以获得更大焦深的无衍射线结构光,解决了单个正等腰三角棱镜小角度加工困难的技术问题。采用几何光学理论分析了产生无衍射线结构光的原理,计算了无衍射线结构光的相关参数。由衍射积分理论分析和模拟了新型光学元件后的光强分布特性。研究表明,平面波正面入射新型光学元件可以产生具有大焦深的无衍射线结构光。

A novel optical element-step refractive index combined triangular-section prism generating non-diffracting linear structured beam with longer distance is proposed.This element is designed with gluing positive and negative isosceles triangular-section prisms.Its property is the same as single positive isosceles triangular-section prism for beam transformation,and its equivalent index of refraction is decided by the difference of refraction index of positive and negative isosceles triangular-section prisms.Therefore,we can get an equivalent index of refraction closer to 1 by combining positive and negative isosceles triangular-section prisms with the approximate index of refraction.And also the non-diffracting linear structured beam with longer distance can be obtained.The technical problem of difficulty in machining the small bottom corner is solved.The formation mechanism of the non-diffracting linear structured beam is analyzed by geometrical optics,and the relevant parameters are also calculated.The intensity distribution is simulated by diffraction and interference theory.The results show that when a plane wave illuminates on the novel optical element,a non-diffracting linear structured beam is formed in longer distance.