One alternative is to apply a single layer on a relatively thick, highly reflecting mirror substrate. It could be a high-index dielectric material or a metallic covering. Furthermore, spatially changeable layer thickness dielectric Variable reflectivity mirror is conceivable. The spatial dependence can be added, for instance, by using a mask to deposit a material flux that is dependent on location. To create mirrors whose reflectivity depends exclusively on radial direction, the substrate is frequently rotated during deposition.
Other manufacturing techniques are also possible, like the spatially dependent modification of reflection properties after the production of initially homogeneous mirrors. If such surface modifications are carried out by laser light, a large range of reflectance forms can be produced.
It should be emphasized that Fractional handpiece will not be produced by a simple Gaussian variation in the layer thickness values of the Bragg mirror. This is because the interference conditions in such a mirror cause the reflectance to have a complex dependence on the Bragg wavelength. The variable reflectance could differ slightly from a flat surface or a prescribed curved surface. These modifications could be minimal for a lot of applications.
Be aware that variations in the thickness of the entire Oem laser head as well as interference effects in dielectric coatings may result in variations in optical phase alterations in addition to variations in reflectance. Only a very small minority of mirror manufacturers can create variable reflectivity mirrors, and those mirrors are quite uncommon in second-hand mirrors.
Applications of Mirrors with Variable Reflectivity
In lasers with unpredictable resonators, variable reflectivity mirrors are typically employed as output couplers. The laser beam would typically tend to get bigger and bigger in a resonator, but in this case the fluctuating reflectivity limits the diameter. Mirrors with Gaussian reflectance are commonly employed. By using this Optical design consulting technique, it is possible to create lasers with high beam quality and output beams that are nearly diffraction-limited, or mode areas with sizable mode areas. Several high-power lasers, including CO2 lasers and various solid-state lasers, are affected by this.
