A new approach to eliminate half-wave holes in short-wave pass filters with layer inhomogeneity

作者：Bao Ganghua; Jiao Hongfei^*; Cheng Xinbin; Liu Huasong; Wang Zhanshan

来源：Acta Optica Sinica, 2014, 34(8): 0831001.

DOI：10.3788/AOS201434.0831001

• Admittance matching
• Half-wave hole
• High-power laser systems
• Inhomogeneities
• Quarter wave stacks
• Repetitive structure
• Shortwave pass filter
• Theoretical performance

Short-wave pass filter is an important optical component in high power laser systems which has the repetitive structure of (0.5LH0.5L)N. But its optical property is significantly influenced by the half-wave hole due to layer inhomogeneity. Analysis by admittance theory shows the key reason for the presence of half-wave hole: the end point of the admittance locus of the periodic structure based on the quarter-wave stack doesn't return to the initial point again. The greater the deviation, the worse the half-wave hole. By inserting matching layers between high and low index materials, a new method is presented to eliminate half-wave hole. The new short-pass film is designed and successfully fabricated, which has a super wide and smooth region with low reflectance at around second harmonic.The experimental results consistent well with the theoretical performance.

• 出版日期2014
• 单位同济大学