As the use of space-based instruments such as telescopes, satellites and probes increases, a number of companies and research organisations are busy developing innovative coatings for onboard optical components. So, what are some of the most recent advances in the development and application of optical coatings for space-based devices? And, could advances made in the space sector eventually trickle down to other optical coating markets?
There is an arms race taking place in the optics sector, as laser manufacturers continually boost the output of their light sources and shorten pulse durations, while manufacturers of lenses, flats, splitters and mirrors work out how to protect their precision surfaces from the onslaught this increase in power represents.
Higher power lasers and ultrafast pulses are putting greater demands on the thin film coatings protecting the lenses in these systems. Complexity of thin films is increasing, with the number of layers reaching into the hundreds and coating runs lasting days. All of this requires precise deposition machines, and, in recent years, a number of companies have incorporated in-situ broadband optical monitoring into the coaters to improve precision and avoid costly errors.
Optical coating companies are building advanced monitoring and metrology into their production to meet the demands for specialised coatings. Vendors, including Advanced Thin Films in the US and Laseroptik in Germany, are now focusing on implementing monitoring mechanisms within their machinery to get better control over the deposition process, and also investing in metrology equipment to test the finished product.
While optics can be used to manipulate light in a variety of different ways, whether that’s through a lens, a mirror, beam splitters or filters, what sharpens the optical properties of these components are their coatings. Coatings are applied to virtually every optical device and are essentially used to control light. They are used in numerous applications, from barcode scanners, which have anti-reflection coatings as well as wear-resistant coatings, to cell phone cameras, to optics used in high-power laser systems.