Evaporated Coatings Inc. is a leading provider of dielectric mirrors coatings and applications. Please choose from the list of services to best determine your needs!

Crystals and Semiconductor Materials

Fiber Optic Devices

Glass Substrates

Plastic and Molded Polymer Optics

Laser Mirror Coatings

dielectric coatings

ECI Can Design a Custom Solution

A dielectric mirror is designed from multiple layers of transparent optical materials, like thin-film coatings, dielectric coatings, and interference coatings. The Fresnel reflection coefficient from an only interface between two different materials is not big. However, many interfaces’ reflections interfere and result in a high reflectivity of the device.

The Bragg mirror is the most common design and it leads to the biggest possible reflectivity for a number of materials and layer pairs. Dichroic mirrors can also be designed by using controlled properties for distinct wavelengths.

How are they designed?

To properly design a dielectric mirror, there have to be certain criteria, like:

  • Anti-reflection properties
  • A mix of reflectivities at different wavelengths
  • A certain chromatic dispersion profile
  • Broad reflection ranges
  • Specific polarization properties
  • A minimum sensitivity to expansion errors

These designs are only found by using numerical optimization algorithms. It is very challenging, as the mirrors need certain parameter space and high dimensionality. 

Designing a mirror is not an easy task. Sometimes, there has to be a compromise between the required number of layers, growth precision and obtained optical properties.

How are the mirror properties calculated?

A mirror’s reflecting properties are calculated with modeling software based on a matrix method. Every layer is associated with a 2-by-2 complex matrix. Moreover, each matrix is multiplied so it results in a matrix of the whole layer structure. From here, the amplitudes of waves can be calculated. The properties of chromatic dispersion are the result of the frequency dependence of the transmission/reflection coefficients. This can be calculated through Fresnel equations.

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