1.
光刻机是现代工业的集大成者,其最核心的两大部件为光源与光学镜头。我国研制的某型号光刻机的光源辐射出某一频率的紫外光,光刻机光学镜头投影原理简化图如图所示,等腰直角三角形ABC为三棱镜的横截面,半球形玻璃砖的半径为R,O为球心,
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmo%3E%27%3C%2Fmo%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
为玻璃砖的对称轴。间距为
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsqrt%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmsqrt%3E%3Cmi%3ER%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
的a、b两束平行紫外光从棱镜左侧垂直AB边射入,经AC边反射后进入半球形玻璃砖,最后会聚于硅片上表面的M点,M点位于
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmo%3E%27%3C%2Fmo%3E%3Cmi%3EO%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
的延长线上。半球形玻璃砖的折射率为
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsqrt%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmsqrt%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
, 来自棱镜的反射光关于轴线
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmi%3EO%3C%2Fmi%3E%3Cmo%3E%27%3C%2Fmo%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
对称,光在真空中的传播速度为c。
(i)要使射向玻璃砖的光线最强,三棱镜的折射率至少为多少?
(ii)紫外光从进入玻璃砖到传播到M点所用时间为多少?
![](http://tikupic.21cnjy.com/ct20241o/a5/fe/a5fe334a2f77a8cbacc9501421d0abdd.png)