PVD coating is a process in which the optical coating is applied using thermal energy.
is applied with the aid of thermal energy. The aim is to manufacture high-performance optical components.
What are the advantages of PVD coating?
PVD on glass, metalls and semiconductors
From fused silica to Germanium
Minimum layer stress
Thin films for precision optics
Production of functional surfaces
Mirrors, anti-reflection and filter
PVD stands for Physical Vapor Deposition. This type of coating is a process in which the surface is refined by thermally fused material. In the process, the coating material for the metallic coating is vaporized. The result is surfaces that have excellent optical properties.
The coating process consists of seven steps. In the first step, the equipment is prepared for coating. The evaporators are filled with material.
For PVD coating, these are typically oxides, fluorides, sulfides and metals such as gold, chrome, silver and aluminum. In the second step, the cleaned optics are fixed in the system. Then the vacuum chamber is closed and the vacuum pumps are started. After reaching the starting pressure, the coating is started in the next step. The thickness of the coating is adjusted with regard to the planned application. Thus, it is possible to optimize the properties of a coating for a wavelength, an angle of incidence or polarization.
We coat metals according to customer specifications and optimized for the corresponding applications. The offer ranges from the production of individual parts to large-scale production. PVD coating of optical glasses takes place in a high vacuum. To achieve the desired optical properties, the individual layers must be precisely controlled during PVD coating. Most coatings are produced by thermal vapor deposition. For this purpose, evaporators are required, which are located at the bottom of the system. The optics to be coated are thereby fixed in a rotating calotte.
PVD coating is done with different metals:
- Gold
- Silver
- Aluminum
- Rhodium / Platinum / Chrome
Aluminum is easy to evaporate and for this reason is used for applications from UV to NIR. Coating with aluminum is the most common method for making mirrors. However, the reflectivity of aluminum decreases over time.
When PVD coating with aluminum, oxide forms on the surface after some time. However, at the same time this protects the surface from further oxidation.
Optical coatings made of metals sometimes have considerable absorption losses. For this reason, the reflection is too low for many technical applications. One way to increase the reflection is to apply additional dielectric layers to the metal coating. Dielectric coatings reduce absorption and improve reflection. For highly reflective mirrors, on the other hand, dielectric coatings are used exclusively. These coatings transmit the non-reflective part and can thus achieve very low absorption values. Such optimized PVD coatings are optimized for a specific wavelength or laser and in this way achieve excellent reflection values of up to 99.9 %.
Optical coatings for CO2 lasers are designed to meet the highest demands. These coatings are used in laser cutting, laser marking and internal optics.
Surfaces treated with our high-quality PVD coatings are characterized by high resistance to environmental influences, even though the coatings are extremely thin, measuring only a few nanometers or micrometers. Metallic coatings are only suitable for a limited range of applications due to their high absorption.
Aluminum is easy to evaporate and for this reason is used for applications from UV to NIR. Coating with aluminum is the most common method for making mirrors. However, the reflectivity of aluminum decreases over time.
When PVD coating with aluminum, oxide forms on the surface after some time. However, at the same time this protects the surface from further oxidation.
Here you will find our overview of optical mirrors