Anti-Reflective Coatings (AR)
Coating Type Properties and Applicaitons
Single Layer MgF2 Applied to materials with refractive indices from 1.45 to 2.4.  The most popular AR coating for visible spectrum.  It is insensitive to change in incidence angle.
Multilayer Used to provide low reflectance with in a narrow durable wavelength band for most laser applications. Minimum reflection can be less than 0.1%.
Broadband Multilayer Excellent performance over a broad range of spectrum.  Coating performance is sensitive to angle of incidence.
Dual Wavelength Band Low reflectance at two widely spaced wavelengths, such as Nd:YAG Laser(1064nm) and its SHG(532nm).

Single Layer MgF2 Anti-Reflective Coatings (SAR)

Magnesium fluoride(MgF2) is probably the most widely used thin film material for optical coatings.  Its performance is not outstanding but represents a significant improvement over an uncoated surface.
Multilayer Anti-Reflective Coatings (VAR)
Multilayer AR coatings can reach low reflectivity at center wavelength.  It is often applied to single laser wavelength or multiple closely spaced wavelength system to guarantee the lowest loss for center wavelength.  Wavelength range for Multilayer AR coatings range from 250nm to 2200nm.  Center wavelength and damage threshold are important to the selection of suitable coating.
Multilayer Broadband Anti-Reflective Coatings (WAR)
In contrast to single layer MgF2 broadband AR coating, Multilayer Broadband AR coating can reach higher transmission in broadband spectrum.  It is ideal for a wide range of multi-wavelength laser and white light applications. Wavelength range and reflectivity of the Multilayer Broadband AR Coating is determined by the incident angle.
Dual Wavelength Band Anti-Reflective Coatings (DAR)
This coating allows two center wavelengths radiation to pass through the substrate with high transmission.  Dual Wavelength Band Anti-Reflective(AR) Coatings is often used in frequency doubling systems or multi-laser output system such as Nd:YVO4 laer(1064nm) and its second harmonic generation(SHG) of green laser(532nm).
Partial Reflective Coatings
Coating Type Properties and Applications
Narrow Band Provide 50% reflection and transmission at an angle of 45 incidence for a single wavelength.  Perfect for beamsplitters application.  Transmission/Reflection (T/R) ratio is 20/80.
Broad Band Provide 50% reflection and transmission over a wide bandwidth.  We can provide coatings with different R/T ratios at any specific angle of incident.
Single Wavelength and Partial Reflective Coatings (SPR)
When a narrow wavelength radiation is incident on SPR coating, part of the radiation is reflected and the other part is transmitted.  This coating always show a high reflectivity for S-polarization radiation and high transmission for P-polarization radiation.  The main application of this coating is for a beamsplitter with 45 angle of incidence.
Broadband Partial Reflective Coatings (BPR)
BPR coating has similar performance to that of SPR coatings.  However, BPR coating can split the incident radiation over a wide spectrum, not SPR.  
High Reflective Coatings (HR)
Coating Type Properties and Applications Wavelength Range
Dielectric High Reflective Coatings Provide high reflectance over a broad bandwidth.  Ideal for a tunable laser or in white light applications. 250nm ~ 2200nm
Metallic High Reflective Coatings Low peak reflectance, mechanical durability and high damage threshold.  Insensitive to angle of incidence and polarization. near-UV, visible and near-IR
Dielectric High Reflective Coatings (DHR)
Dielectric coating can produce very high reflection (more than 99.8% at designed wavelength).  They are commonly used in a single wavelength laser cavity where the lowest cavity loss at a center wavelength is essential.  Center wavelength range from 250nm to 2200nm for DHR coatings.  
Metallic High Reflective Coatings (MHR)
Red Optronics can offer MHR coatings made of Au, Ag, AI, Cr, or Ni-CR.  These coatings are applied where a consistent high reflection over a wide spectral range is required.  MHR reflectivity is not as high as DHR coatings but it can cover near-UV, visible and near-IR spectrum.  To prevent metallic coatings from oxidization, MHR coatings have dielectric overcoat.  


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