Figure 4. Evaporative deposition produces porous coatings that can absorb moisture, while IAD reduces this problem and IBS completely eliminates it .
Depending on the application, there can be several different challenges that laser engineers need to address in the development of new-generation laser sources, stability, beam quality and certain power levels are key to most remote-sensing or medical applications, while in the defense market it is size, weight and efficiency that are even more important and difficult to achieve. For a system to become smaller, lighter and more powerful, it means having a narrower spot size and higher fluencies that optical components must be able to withstand. The lifetime and stability of the weakest component will therefore define the longevity of the system itself, with the need to give special attention to the production of each individual component.
Continuous irradiation going through a volume of amorphous glass will run into all the impurities and potential absorbers typical for the actual wavelength. In the 2 µm region, the biggest foes are OH absorption bands, which cause local heating of glass that results in thermal lensing and distortions. This well-known issue is easily resolved with the right selection of infrared-grade fused silica (OH concentration <5 ppm) or calcium fluoride optics.
Altechna solution for 2 µm applications
The development of new-generation optical components capable of managing today’s challenges is a complex process. It involves more than one discipline, ranging from material science to engineering. Altechna engineers have identified several technological bottlenecks of laser systems that work in the region around 2 µm and prepared a full industrial solution. High-quality optical components for laser resonators and delivery optics are now available in prototyping quantities, as well as for mass production.
*NOTE: No damages were found while testing, therefore, LIDT value could not be evaluated. LIDT value should be higher than maximum fluence value used in the test. This fluence value is written in the specification table .
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5.Trey Turner, Laser Focus World (2011), Thin-film coatings: Military laser technologies challenge optical-coating manufacturers, <https://www. laserfocusworld.com>.
6.Tested at Lidaris, JSC.