Inputs
Use consistent units; validate ranges.
v1.0
Model notes: effective indices are computed for s-polarization using n_eff = sqrt(n² − (n_a·sinθ)²) with ambient n_a=1.
HR width estimate Δλ
—
HR width estimate (octave)
—
nH,eff / n₂,eff
—
OD at λ₀ (max shown)
—
Spectra settings
AOI: –° | ns: –
Export tips: Use Export CSV to copy the layer stack into spreadsheets / coating tools.
Design results
Charts
Spectra
Layer stack
About
Structure thickness bars are in nm;
OD curve uses OD = −log10(1−R₀) at λ₀.
OD curve uses OD = −log10(1−R₀) at λ₀.
Click Compute (top right) to generate the Chirped design and spectra.
S1 structure
p-modulated quarter-wave
High Index Layer (H)
Low Index Layer (L)
S2 structure
extended low-index thickness
High Index Layer (H)
Low Index Layer (L)
OD vs number of layers
evaluated at λ₀
Reflectance (R)
%
Transmittance (T)
%
Absorbance (A)
%
R, T, A
combined
Layer order is from ambient side to substrate side (1…2m).
| # | Type | n_eff | t_S1 (nm) | t_S2 (nm) |
|---|---|---|---|---|
| Compute to generate the layer stack. | ||||
Notes: This tool gives a quick analytic estimate of HR-zone width and OD at λ₀ for quasi-notch structures in s-polarization.
What this tool does
This tool can be used as a starting design for high reflectors or dispersive mirrors for ultrafast laser applications.
Layer thicknesses of such mirrors deviate from the quarter-wave thicknesses.
If 𝜆0 is the central wavelength of the HR zone and 𝜖 is a chirp parameter, then physical thicknesses of coating layers are evenly distributed between 0.25 ⋅(1 +𝜖) ⋅𝜆0/𝑛𝐻,...,0.25 ⋅(1 −𝜖) ⋅𝜆0/𝑛𝐿 (thicknesses are decreasing as in Figure of S1 and S2 structures) or between 0.25 ⋅(1 −𝜖) ⋅𝜆0/𝑛𝐻,...,0.25 ⋅(1 +𝜖) ⋅𝜆0/𝑛𝐿 (thicknesses are increasing).
It calculates:
Layer thicknesses of such mirrors deviate from the quarter-wave thicknesses.
If 𝜆0 is the central wavelength of the HR zone and 𝜖 is a chirp parameter, then physical thicknesses of coating layers are evenly distributed between 0.25 ⋅(1 +𝜖) ⋅𝜆0/𝑛𝐻,...,0.25 ⋅(1 −𝜖) ⋅𝜆0/𝑛𝐿 (thicknesses are decreasing as in Figure of S1 and S2 structures) or between 0.25 ⋅(1 −𝜖) ⋅𝜆0/𝑛𝐻,...,0.25 ⋅(1 +𝜖) ⋅𝜆0/𝑛𝐿 (thicknesses are increasing).
It calculates:
- This tool estimate the width of HR zones of chriped mirrors at normal incidence and plot the chriped mirror design structure.
- Effective indices for s-polarization at the given incidence angle.
- Layer thickness sequences for two quasi-notch structures (S1, S2).
- OD at λ₀ as a function of layer count.
- HR-zone bandwidth estimates (Δλ) for S1 and S2 can be estimated as: Δ𝜆 =Δ𝜆𝑄𝑊𝑀 +𝜖 ⋅𝜆0. From this tool one can estimate the HR zone and find a reasonable 𝜖 value for your design problem..
- The width of the HR zone is not dependent on the number of layers. Of course, if the number of layers is growing, the average reflectance over the HR zone is increasing.
Engineering note: This is not a full transfer-matrix spectral simulation. For production-grade design, you should verify with a full optical model (TMM) using dispersive n,k and real substrate stacks.
ASTRACOAT Chriped Filter Design — UI rebuild for clarity and reliability (no collapsibles, stable charts, exports).