实验研制了针对波长248 nm KrF准分子激光的零级抑制石英相位掩模器。用双层掩蔽和图形转移技术,在双面抛光的石英基片上以CHF3/O2为反应气体,用反应离子刻蚀技术制作了具有良好完整性、周期1.085 μm的石英相位掩模器。实际测量表明其零级衍射效率被抑制到5.97%。

A method for fabricating zero order nulled silica grating phase masks for 248 nm KrF excimer laser is described. Perfect silica mask gratings with the period of 1.085 μm have been produced using bilayer resist and proper techniques for pattern transfer. Exprimental measurements show that the zero order diffraction efficience is less than 6%. Etch of silica substrates is performed by reactive ion etching in CHF 3/O 2. Theoretical analysis shows that these phase masks can be used for producing grating pattern by self-interference and for fabricating UV written fiber Bragg gratings.