Optical Coating Technologies

Optical thin-film coatings can be deposited using various methods, each impacting their performance characteristics significantly.

Traditionally, methods like thermal and electron-beam (e-beam) evaporation, including ion-assisted e-beam evaporation (IAD), have been widely used for multilayer coatings required in high-performance mirrors and filters.

These methods, however, often result in "soft" coatings due to their inherent porosity, leading to durability issues, moisture absorption, wavelength shifts with temperature changes, and noticeable scattering.

In contrast, Notch Optics employs a sputtering deposition process for all its optical filters, which offers distinct advantages. Originally developed for magnetic disk drive heads and later adapted for optical applications, sputtering produces hard refractory oxide thin films that match the hardness of glass substrates.

This method ensures stable and reproducible deposition of hundreds of low-loss, reliable thin-film layers with high precision in optical thickness.

Ion-assisted Ion-beam Sputtering (IAD) enhances the sputtering process further by improving film density and reducing moisture absorption, temperature sensitivity, and scattering.

This results in very dense, low-scattering films ideal for demanding optical applications. Surface morphology studies using atomic force microscopy highlight the superior packing density of sputtered films compared to evaporated counterparts, maintaining substrate-level smoothness.

Historically, sputtering faced throughput limitations, particularly for larger filters needed in high-volume production. Notch Optics has overcome this challenge by developing advanced process technologies that enhance deposition rates and uniformity without compromising optical performance.

Their proprietary "optical monitoring" system ensures precise control over film thickness and spectral features, making sputtering a viable option for complex optical filters on a large scale.

Notch Optics continues to innovate in sputtering technology, improving efficiency and expanding capabilities, thereby maintaining its reputation for producing high-performance optical coatings suited for a wide range of applications in optics and photonics.