Monochromatic Monitoring Simulation is  OptiLayer tool that is aimed for performing experiments on computational manufacturing of optical coatings.

Monochromatic Monitoring Simulation option allows you to perform computational experiments simulating deposition processes in vacuum chambers equipped with monochromatic monitoring devices.

You can specify all major factors causing errors in layer thicknesses:

• Mean deposition rates of the materials and their fluctuations;
• Random and systematic deviations of refractive indices;
• Mean shutter delay and its fluctuations;
• Incidence angle, scan interval, monitoring spectral range and number of wavelength points;
• Level of random noise and drift in measurement data.

Monitoring wavelengths are taken from the Monitoring spreadsheet.

These wavelengths can be specified by an optical coating engineer or chosen automatically with the help of the advanced monitoring strategies.

Example illustrating advanced monitoring strategies.

8-layer AR coating working in the spectral range from 650 nm to 750 nm, and in angular range from 0 to 70 degrees. Light is non-polarized. Substrate is Suprasil, layer materials are Nb₂O₅ and SiO₂.

Simulation parameters:

• Deposition rates are 0.5 nm/s (H-material) and 0.8 nm/s (L-material);
• Fluctuations of the deposition rates of 5% and 10%;
• Systematic errors in H-refractive index is 1%;
• Random errors in H-index is 0.5%;
• Average shutter delay and its fluctuation of 0.5 s and 0.1 s, respectively;
• Noise in measurement transmittance signal is 0.015%;
• Time interval between measurements of 1 s;
• Calibration drifts of the monitoring transmittance signal is 0.01% with correlation time 5 s.

Monitoring wavelength is 700 nm - middle of the antireflection spectral range

Monitoring wavelength of 621 nm is obtained with the help of the advanced monochromatic monitoring strategy of OptiLayer.

Monochromatic monitoring simulations help to production yields in the case of these two monitoring wavelengths. 

Estimation of the production yield \(Y\) is the ratio of successful and total simulated runs.

To distinguish between successful and unsuccessful deposition runs, the range targets are to be introduced. In this problem, the range target is defined as \(R\le 9.5\%\)  in the spectral range from 650 nm to 750 nm.

With monitoring wavelength of 700 nm production yield is 0%:

All simulated coatings are outside of the allowed corridor \(R\le 9.5\%\).

With monitoring wavelength of 621 nm production yield is 0%:

All simulated coatings are inside of the allowed corridor \(R\le 9.5\%\).