Metal-Dielectric Dual Bandpass Filter

gds

This filter transmits two fairly narrow bands of wavelengths centered at 770 and 920 nm.
8 W1 m, W$ l7 s8 g9 @8 |+ x0 lPlot of metal-dielectric design

This design is for normal incidence on a BK7 (ordinary) glass substrate. Three materials are used: Au, SiO2, and TiO2. Starting with a thin, one-layer design, TFCalc's needle/tunneling method produced a sequence of designs of increasing complexity. The design (whose performance is shown above) consists of 13 layers.
Here is the design, with the first layer closest to the substrate and thickness given in nm:

    AU        16.58
4 x! ]: b  n# x/ A: {8 |    SIO2     115.39
    TIO2      96.33
    SIO2      49.67
6 o, N0 |4 X, v# P    TIO2      39.24
    SIO2     152.40
) [+ L0 B4 b4 [* j+ a; H( ]    TIO2      93.69
    SIO2     270.66
9 {7 J2 O: g8 t! R8 i8 `    AU         4.16
+ o# p9 @. |/ Y. ]- d- C7 `    SIO2      10.49
9 U7 ^/ T  ~7 q6 Z    TIO2      95.25
    SIO2     102.01
    AU        10.76