摘要
将一种可旋转的双棱镜引入到相位掩模技术中以改变光栅的写入Bragg波长.在该系统中,光纤光栅是由来自可旋转双棱镜所形成的波长为248nm的紫外干涉条纹写入的,其中,相位掩模被用作1级衍射光的分束器,通过双棱镜的旋转可改变两写入光束的交叉角.为了初始化Bragg波长的参考值,双光栅的顶角由相位掩模的1级衍射角和双棱镜的折射率确定.因为在～100nm范围内两光束的非对称旋转对光栅周期的改变是5×10-4nm,双棱镜引入的光栅的闪耀可忽略.当Bragg波长的移位为1nm时,棱镜最大的旋转角为～1degree,最小的旋转角是～2.4min.与Talbot干涉仪中平面镜的旋转角～23s/nm相比,该相位干涉仪中棱镜的旋转精度降低了2～3个数量级.
A rotatable biprism is introduced in phase mask technique to change the inscribed Bragg of grating. In this system, the gratings are inscribed by the UV interference fringes of 248 nm derived from a rotatable biprism, where the phase mask is used as a beam splitter, and the biprism is rotated to change the intersection angle of two beams. For initializing the reference quantity of Bragg wavelength, the vertex angles of the biprism are determined by the ？1 diffraction angle of phase mask and the refract index of the biprism. Because the change of grating period caused by the asymmetrical rotation of two beams is limited to 5×10-4 nm at a tunability of the Bragg wavelength of ~100 nm, the tilt of grating caused by the rotation of the biprism can be ignorable. As the shift of Bragg wavelength is 1 nm, the maximum rotation angle of the prism is ~1 degree, and the minimum rotation angle is ~3 minute. By contrasting with the rotation angle ~23 second/nm of the mirror in Talbot interferometer, the rotation precision of the prisms is decreased by two or three orders of magnitude in this phase mask interferometer.
出处
《光子学报》
EI
CAS
CSCD
北大核心
2009年第12期3194-3197,共4页
Acta Photonica Sinica
基金
Supported by the S&T Project of Yunnan Province(2007F181M)
