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Optical Coating
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Anti-Reflective
Coatings (AR)
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| Coating Type |
Properties and
Applications |
| 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. |
| Multi-layer |
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
Multi-layer |
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). |
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Single Layer MgF2 Anti-Reflective
Coatings (SAR)
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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.
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Multi-layer Anti-Reflective Coatings (VAR)
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Multi-layer 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
Multi-layer AR coatings range from 250nm to 2200nm. Center
wavelength and damage threshold are important to the selection
of suitable coating.
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Multi-layer Broadband Anti-Reflective Coatings (WAR)
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In contrast to single layer MgF2 broadband AR coating,
Multi-layer 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 Multi-layer Broadband AR Coating is
determined by the incident angle.
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Dual Wavelength Band Anti-Reflective Coatings (DAR)
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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).
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Partial
Reflective Coatings
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| Coating Type |
Properties and
Applicaitons |
| 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. |
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Single Wavelength and
Partial Reflective Coatings (SPR)
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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.
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Broadband Partial
Reflective Coatings (BPR)
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BPR coating has similar
performance to that of SPR coatings. However, BPR coating
can split the incident radiation over a wide spectrum, not SPR.
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High Reflective
Coatings (HR)
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| 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.
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near-UV, visible and
near-IR |
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Dielectric High Reflective Coatings (DHR)
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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.
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Metallic High Reflective Coatings (MHR)
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New Rise Optics 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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