ISSN:
1572-9559
Keywords:
Filters
;
Infrared
;
Metallic mesh
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract By using a Michelson interferometer in the asymmetric mode with helium cooled bolometer, we have measured with precision the complex transmittance and reflectance of metallic meshes in the wavelength region 0.7〈λ/g〈5, where λ is the wavelength, and g is the period of the mesh. For λ≅g we observed a minimum power reflectance smaller than 10−4 at normal incidence. The important variations of the transmittance with the angle of incidence have been thoroughly investigated. Changes around the maximum transmittance are explained by the propagation of diffracted modes. Phase measurements show that a sharp dip appearing at λd with 1〈λd/g〈1.8 is related to the finite thickness of the mesh. From our measurements as well as other data precedently published it appears that there is a linear dependance between λd/g and the relative width of the slots of the mesh. All these deviations from classical models must absolutely be taken in account when designing high performances far infrared filters.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01007035
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