Metallic Mirror Coating


Different types of parabolic, spherical, and flat mirrors are produced having different types of mirror substrates. These products have a variety of metallic and dielectric coatings that make them suitable for various applications. The various types of mirror coatings include Protected Aluminum, Enhanced Aluminum, UV Enhanced Aluminum, Bare Gold, and Protected Gold etc that are used for visible applications.

UV and DUV enhanced aluminum is used for UV and visible applications while Bare and Protected Gold offer high reflectance for near Infrared and Infrared Wavelength.

First Surface and Second Surface Mirrors

All the mirrors you use are first surface mirrors. This mirror has a high reflectance coating deposited on the front surface of a variety of different types of glass, metal or semiconductor substrates. The other surface of the mirror may be clear or ground and the mirror is oriented so that the coating faces the source. They are widely used in precision optics applications.

Second surface mirror uses the same coating technology but the coating is applied to the bottom surface and over coated with the black paint. The other surface of the second surface must be clear and the mirror is oriented in the way that the incident light first passes through the transparent substrate material and then gets reflected by the coating. This protects the coating layer from scratch and oxidation but this type of mirror are unsuitable for most precision optics applications.

·         The mirror substrates on the second surface mirror leads to chromatic dispersion of the light incident on its surface.


·    Reflection at the substrate leads to ghost images indicated by the dashed orange line. An unwanted second reflection occurs as the light exits the substrate that decreases the net reflectance of the mirror. Also, the stray ghost reflection is observed when the light bounces between the coated and non-coated surfaces of the substrate.

Enhanced or Protected Mirror Coating

The metal coating is delicate and needs a protective coating over its surface. The unprotected metal coating should never be touched or cleaned with anything but clean and dry in air. A dielectric metal coating on the metallic mirrors improves handling of the component, increases the durability of the metal coating and provides protection from oxidation. The coating also enhances the reflectance of the metal coating in specific spectral regions.

Location: Australia

Comments

Post a Comment

Popular posts from this blog

Everything You Want to know About Collimating Lens from Thorlabs or Elsewhere

Image
Collimating lenses are optical lenses that help in making the light entering into the spectrophotometer parallel. With a collimating lens from Thorlabs or elsewhere, one can control the field of view, spatial resolution of their setup, collection angles for sampling and illumination. Why are they important in the first place? One of the prime reasons for use of the collimating lens is high divergence result of a laser diode. It is made up of aspheric lenses, they do not pose spherical aberration. Collimating lenses are usually picked as and when a collimated beam requirement is between one and five millimetres. Where are they used and how are they used? Collimating lens is placed inside a collimator. An Optical collimator is utilized for calibration, testing and measurement. In one of the types of the collimator, patterns are projected into infinity. When a target is kept in the focal plane of a collimator, the uniform target seems extremely near. This phe
Read more

Collimating Lens from Throlabs for LED

Image
LED has a small protective dome over the diode that is commonly known as the primary optic that serves to protect and shape the output of the small diode. But light from the primary optic of the LED is broad for most application and lacks intensity for long distance. To reduce this drawback LED fixtures use secondary fixtures like collimating lens from Thorlabs or other labs, reflectors, TIR optics etc that collects light and magnifies its intensity towards the target. If you wish to create lenses and reflectors for LEDs, then you need to use some logical ways apart from just scaling them down from the light source. This is because LED has much smaller form factors than other light sources and also differs in the way it emits light . Use of collimating lens in LED          The collimating lens of the LED undergoes the process of Total Internal Reflection or TIR. TIR is defined as the complete reflection of a ray of light within a medium such as water or glass from the
Read more

Importance of Collimating Lens

Image
The collimator is a device that changes the diverging light or other radiations from a point source into a parallel beam. This specific feature of the device makes it an important part in spectroscopy and geometric and physical optics. An optical collimator consists of a tube with a convex lens at one end and an adjustable aperture at the other. The collimating lens of Thorlabs inside the collimator produces rays into the parallel beam so that the image can be viewed without parallax. Uses of Collimating Lens The collimating lens of Thorlabs or other labs is curved optical lenses that are used by the user to control the field of view, collection efficiency and spatial resolution of their setups. It is also used to configure illumination and collection angles for sampling. Use of Collimating Lenses in Radiology The collimator lens is also used in radiology where a collimator is an arrangement of absorbers for limiting beam of X-rays, gamma rays, or nuclear par
Read more