Optical Coating

Photonchina owns different kinds of coaters, both overseas brand and domestic brand, to supply different coatings as follows,

• Antireflection Coating(AR)
• Partial Reflection Coating(PR)
• Beamsplitter Coating
• High Reflection Coating(HR)
• Metal or Metallic Coating.

We can provide coatings with high surface quality, high damage threshold coatings, and more.

 

Anti-Reflection Coating (AR coating)

Photonchina offers a wide range of antireflection coatings covering the ultraviolet, visible, near infrared, and infrared regions. For most uncoated optics, 4% or more of incident light is reflected at each surface, resulting significant losses in transmitted light level. Utilizing a thin film anti-reflection coating can improve the overall transmission, as well as minimizing stray light and back reflections throughout the system. The AR coating can also prevent the corresponding losses in image contrast and lens resolution caused by reflected ghost images superimposed on the desired image.

Four types of AR coating: the Single Layer Magnesium Fluoride AR coating, the Broadband Multilayer AR coating, and Multilayer AR V-coating.

A single layer Magnesium Fluoride AR coating is the most common choice that offers extremely broad wavelength range at a reasonable price. It is standard on achromats and optional on our N-BK7 optical parts like plano-convex spherical lenses, cylindrical lenses, quartz waveplate etc. Comparing to the uncoated surface, the MgF₂ provides a significant improvement by reducing the reflectance to less than 1.5%. It works very well over a wide range of wavelengths (400 nm to 700 nm) at angles of incidence less than 15 degrees.

Broadband Multilayer AR coating improves the transmission efficiency of any lens, prism, beam-splitter, or windows. By reducing surface reflections over a wide range of wavelengths, both transmission and contrast can be improved. Different ranges of Broadband Multilayer AR coating can be selected, offering average reflectance less than 0.5% per surface. Coatings perform efficiently for multiple wavelengths and tunable laser, thereby eliminating the need for several sets of optics.

V-coatings offer the lowest reflectance for maximum transmission. With its high durability and high damage resistance, Laser line AR V-coating can be used at almost any UV-NIR wavelength with average reflectance less than 0.25% at each surface for a single wavelength. Valuable laser energy is efficiently transmitted through complex optical systems rather than loss to surface reflection and scattering. The trade off to its superior performance is the reduction in wavelength range. Except for some optical components in our stock which are ready to delivery, most V-coating can be coated on a semi-custom basis.

Dual Wavelength Band, Offer very low reflectance at two widely spaced wave lengths, such as Nd: YAG Laser (1064) and its second harmonic (532).

 

Other types of optical coating

 

COATING TYPE		PROPERTIES AND APPLICATIONS
PARTIAL REFLECTION	Narrow Band	Provide 50% reflection and transmission at an angle of 45° incidence for a single wavelength. Perfect for beamsplitter applications. Transmission/reflection (T/R) ratio of 20/80. Additional T/R ratios for beamsplitter are available upon request.
	Broadband	Provide 50% reflection and transmission over a wide bandwidth. Photonchina also provides coating with different R/T ratios and specific angles of incidence.
BEAMSPLITTER	Laser Line Polarizing Beamsplitters	High reflection for s-polarized and reflection for p-polarized for laser applications.
	Broadband Polarizing Beamsplitters	Wide wavelength bandwidths provide high reflection to s-polarized and antireflection to p-polarized.
	Dichroic Beamsplitter Mirrors	These coatings separate the laser fundamental and the pump wavelength or the fundamental and the second harmonic. They are specifically applied to laser mirrors.
HIGH REFLECTION	Dioeletric High Reflective Coatings	Provide high reflectance over a broad bandwidth and are ideal for tunable laser or white light applications.
	Metallic High Reflective Coatings	Metallic coating have low peak reflectance, mechanical durability and a high damage threshold, but they have an extremely broad bandwidth and low cost. They are insensitive to angle of incident light and polarization.