宽截止窄带高反射滤光膜设计

窄带高反射滤光膜在光通讯、光学探测仪器等领域有着重要应用.探讨了"基片|H(LH)m1aL(HL)m2βCr,M|空气"膜系结构的窄带高反射滤光膜系,讨论了金属Cr层厚度,以及两种不同的匹配膜系对滤光膜特性的影响,计算了Cr层内部的电场分布.结果表明,较厚的金属层可实现更宽的截止带宽,匹配层的加入有效地实现了宽截止带的深截止,使中心波长处导纳为较大值的匹配膜系可以更好地实现滤光膜宽截止、窄带高反射特性;匹配膜层使中心波长处Cr层内部的电场强度趋于零,有效地降低了整个膜系的吸收,提高了反射率.

Design of Narrowband High-Reflection Filter Coating with Wide Stop Band

Narrowband high-reflection filter coatings are very important in optical communication and optical detectors. A kind of narrowband high-reflection filter coating with structure of “substrate H(LH)m1αL(HL)m2βCrM air” was proposed, the influences of Cr thickness and two different matching film stacks on the characteristics of the filter coating was discussed, and the distribution of the internal electric field was calculated. Results show that a wider stop band in reflection can be realized with a thicker metallic layer and inserting a matching stack will produce a deep rejection of the stop-band. The matching stack leading to a greater admittance helps obtain a wide stop-band and narrow-band high reflection, and also produces zero electric field intensity in the Cr layer at the central wavelength, which consequently reduces the absorption and enhances the reflectance of the filter.