| 摘要 |
<p>According to one aspect, the invention relates a spectral band-pass filter, which is optimized for the transmission of an incident wave at at least a first given central wavelength lambda0, and which includes: a metal grating having a thickness (t) greater than approximately lambda0/50 and including at least a first set of substantially identical, parallel slots having a width (W) less than around lambda0/10, and being spaced apart periodically or quasi-periodically according to a first period that is less than said first central el wavelength, a layer of dielectric material having a thickness (h) and a given refractive index (ng), which is coupled to the metal grating to form a waveguide for the waves diffracted by the grating, said first period of the grating being designed such that only orders 0 and ±1 of a wave having normal incidence and a wavelength lambda0 are diffracted in the layer of dielectric material, the assembly of the dielectric layer and grating being suspended, during use, in a fluid having a refractive index of close to 1.</p> |
