Deposition error compensation for optical multilayer coatings. I. Theoretical description

Area of Science:

• Optical Engineering
• Materials Science
• Thin Film Technology

Background:

• Manufacturing complex optical coatings with multiple layers presents challenges, particularly with non-dense deposition techniques.
• Deposition errors can compromise multilayer performance and disrupt monitoring and control of subsequent layers.

Purpose of the Study:

• To describe a versatile deposition error compensation program for simulating and controlling the manufacture of optical multilayers.
• To establish optimal monitoring strategies for multilayer fabrication through statistical analysis of simulations.

Main Methods:

• Developed a deposition error compensation program incorporating effective medium theory for porous layers.
• Simulated random errors in layer thickness, porosity, and included measurement errors.
• Evaluated monitoring strategies for a sharp edge filter manufactured using three physical vapor deposition methods.

Main Results:

• The program enables simulation and real-time control of multilayer optical coating manufacture.
• Effective medium theory accurately models porous layers by relating optical constants to microstructure.
• Statistical analysis identified the most effective monitoring strategies for specific multilayer designs and deposition methods.

Conclusions:

• Deposition error compensation is crucial for achieving desired optical performance in multilayer systems.
• The developed program provides a versatile tool for optimizing optical coating manufacturing processes.
• Understanding and mitigating deposition errors through simulation and compensation is key to reliable multilayer fabrication.