| 主权项 |
1. An omnidirectional nonmetallic mirror prepared by a process comprising the steps of:
A) defining a base structure including at least two layers, layer a and layer b, made of different non-metallic materials, layer a and layer b being each associated with an elementary matrix incorporating physical parameters of the layer and parameters of light passing through the layer, the physical parameters including thickness da of layer a, thickness db of layer b, refractive index na of layer a and refractive index nb of layer b, the parameters of the incident light including wavelength λ, angle of incidence θ, TE mode and TM mode; B) defining a heterostructure by applying a selected substitution σ to the base structure, the substitution σ replacing one layer in the base structure with a predetermined combination of layer a and layer b, the heterostructure defined by the iterated action of σ a having a total of N layers with each layer j being associated with its transfer matrix Sj incorporating the physical parameters of layer j and the parameters for light passing through layer j where j is 1 to N; C) calculating a product of matrices
MN=SN SN-1 SN-2 . . . S2 S1 with a computer by a block-wise recurrence defined by σ and according to their arrangement by means of the block-wise recurrence to obtain the transfer matrix MN of the heterostructure defined in step B, from which the heterostructure transmission coefficient T is calculated also by the computer with the formula:T=4(TrMN)2+(aTrMN)2where TrMN is the trace of the matrix MN and aTrMN its antitrace;
D) comparing the transmission coefficient T so obtained with a threshold value Tthresh predetermined in view of the envisaged use of the mirror and
if the transmission coefficient T is below the threshold value Tthresh, for any angle of incidence θ between θ1 and θ2, at the wavelength or over a span of wavelengths being considered, for the TE mode and for the TM mode, the structure is an omnidirectional mirror for the light having an angle of incidence θ lying between θ1 and θ2,if the transmission coefficient T is above the threshold value Tthresh for at least one angle of incidence θ lying between θ1 to θ2, at the wavelength or in the span of wavelengths considered, either for the TE mode, or for the TM mode, identifying the heterostructure as not being an omnidirectional non-metallic mirror and then:
defining another heterostructure by step B with a new substitution a and repeating steps C and D until a non-metallic omnidirectional mirror is obtained, ordefining another base structure in step A and repeating steps B, C, and D; and E) if a non-metallic omnidirectional mirror is identified in step D depositing N layers to form this omnidirectional non-metallic mirror. |
