A-Z Product List
Fabrication and Coating
JDSU designs, develops and manufactures customized multilayer coated laser optics including:
Large Optics
Substrates up to:
High Energy
CW energy damage threshold typically ranges up to 20 kilowatts per square centimeter for coated nonmetallic substrates and up to 100 kilowatts per square centimeter for coated metallic substrates. Values will vary depending on specific substrate material, surface finish and laser wavelength.
Pulsed energy damage threshold for coated mirrors typically ranges up to 12 joules per square centimeter for a one-nanosecond pulse. Values will vary depending on substrate material, surface finish, length of laser pulse and laser wavelength.
Coatings tailored to meet most requirements are available in four general classifications.
Substrate Fabrication
Our modern optical shop fabricates substrates from sophisticated infrared materials such as Germanium and Zinc Selenide to the more popular glasses such as BK-7 and Fused Silica. These substrates are available in sizes up to 19 inches diagonal with flat and curved surfaces. They can be manufactured in virtually any shape and are suitable for most laser applications.
Instrumentation
JDSU designs and constructs its own self-contained, highly specialized measurement equipment for ultra-precise determination of coating reflection, absorption and scatter at selected laser wavelengths.
Ultraviolet
One region of the spectrum which represents state-of-the-art in both lasers and coatings is the near ultraviolet (UV) from 0.25 mm to 0.4 mm. Most of the coating materials which are transparent in the visible become highly absorbing in the UV. Thus new material combinations are necessary. OCLI has developed several coatings for the important laser wavelengths in the UV. In particular, high reflectance designs with extremely good power handling capability are available at 0.249mm (KrF*) and 0.354mm (XeF*). OCLI coatings with high reflectance (> 98%) and high power durability (> 15 J/cm2) at 0.354 mm have been reported by the U.S. Naval Weapons Center at China Lake, California.
The most commonly used substrate in the UV is fused silica, which can be produced with extremely low UV absorption. This material is a suitable substrate for both high reflector coatings and transmitting components. For high reflector applications only, UV absorbing substrates such as BK-7 can be used. Coatings in the UV are typically environmentally durable, meeting the hardness, adhesion, and humidity requirements of MIL-M-13508.
Antireflection Coatings
JDSU antireflection coatings can be applied to substrates up to 44 inches in diameter and will provide less than 0.1% in reflection at any point on the surface for near-normally incident energy. At non-normal incidence, the same low reflection value can be provided if the incident beam is linearly polarized. This coating has proved to be exceptionally stable with time and environmental changes.
Total Reflector Coatings
We routinely apply a dielectric total reflector coating to various substrates such as fused silica, BK-7 and Pyrex®. Substrate sizes up to 30 inches in diameter can be easily accommodated. Reflectance is typically greater than 99.5% at any point on the coated surface.
Beamsplitter Coatings
JDSU has developed a family of beamsplitter coatings to provide reflection and transmission characteristics within 1% of customer-specified values. The broad bandwidth of this design ensures uniform spectral performance even when the coating is applied to very large substrates.
Polarizing Beamsplitter Coatings
Beamsplitter coatings from JDSU provide high transmission for incident energy, with the E-Vector polarized parallel to the plane of incidence ('p' polarization), and very low transmission is provided for incident energy with the E-Vector polarized perpendicular to the plane of incidence ('s').
The polarizing beamsplitter can be used to convert unpolarized energy to linearly polarized energy or to split a linearly polarized beam into orthogonally polarized beams of equal amplitude. We can guarantee coating thickness uniformity within 1% for parts as large as 23 inches in diagonal.
Damage Threshold
Damage threshold of our coatings at 1.064mm has been measured at several facilities n the United States, including KMS Fusion and the Lawrence Livermore Laboratory of the University of California. These measurements indicate that OCLI coatings at 1.064mm consistently exhibit extremely good reliability in high-energy applications. When subject to a one nanosecond pulse, OCLI coatings typically withstand 7 to 10 joules per square centimeter. The damage threshold level indicated above has been achieved on beamsplitters up to 16 inches in diameter and on polarizers up to 10 x 18 x 2 inches and represents state-of-the-art performance for these types of coatings.
Instrumentation
We designed and built a 1.064mm test instrument for precisely measuring transmittance and reflectance for energy incidence over a wide range of angles and polarization status. Transmittance and reflectance values can be determined within ±0.02% at any point on optical elements up to 44 inches in diameter. In addition to reflectance and transmittance data, these measurements are used to determine the thickness uniformity and birefringence of the coating when applicable.
Environmental Performance
When applied to hard substrates, our coatings at 1.064mm are guaranteed to pass the hardness, humidity, and adhesion tests of MIL-M-13508. Samples from each coating run are subjected to these tests. If a failure occurs, the parts are considered to be out of specification and are rejected.
Coatings for Continuous-Wave and Pulsed Infrared Lasers
Antireflection Coatings
Due to the high power levels normally associated with continuous wavelength infrared lasers, refractive elements such as lenses and windows are normally avoided. However, in some systems, lenses are required for beam expansion and windows are required to contain the plasma or to provide a barrier between the laser system and the surrounding environment.
For continuous wave carbon dioxide lasers having performance at 10.6mm, a very popular window material is Zinc Selenide. This material is now available in sizes up to 30 inches in diameter with extremely high internal quality. Antireflection coatings can be applied to such windows to provide reflection less than 0.1% per surface. Such coatings can be used with windows having incident energy of several kilowatts per square centimeter at 10.6mm.
For high energy pulsed lasers at 10.6mm, alkali halide materials such as potassium chloride (KCI) and sodium chloride (NaCI) have proven very effective when used in low-humidity environments. We routinely achieve reflectance less than 0.15% per surface on NACI up to 18 inches in diameter. The coating will pass adhesion and hardness tests of MIL-M-13508 and has a typical laser damage threshold of 5 joules per square centimeter for one-nanosecond pulses.
For carbon monoxide (CO) and deuterium fluoride (DF) lasers, different window materials such as calcium fluoride or strontium fluoride are usually selected. Special antireflection coatings have been designed to cover the complete laser bands at these two wavelengths. For example, an antireflection coating for use with a DF laser must provide low reflectance over the wavelength range from 3.6mm to 4.1mm. The exact spectral and environmental performance levels of these antireflection coatings are related to the type of substrate material and the bandwidth requirements of the coating.
Total Reflector Coatings
Mirrors rather than lenses are widely used in high-energy continuous laser systems for beam directing and beam shaping, because there are very few low loss coating and substrate materials that are suitable for refractive components. Damage threshold for totally reflecting components is generally much higher than for refractive components.
Since energy transmittance is not a requirement for totally reflecting components, a wide range of substrate materials can be selected. In moderate power applications, low expansion ceramic materials such as ULE® or Cer-Vit® are used. In applications where incident energy is more than several kilowatts per square centimeter, metal substrates such as copper or molybdenum are used. In systems where incident energy exceeds 10 kilowatts per square centimeter, water-cooled metal mirrors are generally used. We coat the substrate material with a multilayer coating to increase the reflectance in the wavelength region of interest.
Of equal importance is the reduction in thermal loading provided by our high reflectance coating since all energy, which is not reflected from the mirror surface, is usually absorbed in the substrate material. Absorbed energy causes the substrate material to increase in temperature, resulting in deformation of the surface figure of the mirror. We typically achieve reflectance levels of about 99.85% at 10.6mm and 99.9% at 3.85Vm. These coatings can be applied to a wide range of substrate materials and will meet the hardness, adhesion, and humidity requirements of MIL-M-13508. Typical damage threshold for infrared laser mirror coating is approximately 5 to 10 kilowatts per square centimeter for glass or low expansion ceramic substrates and 12 to 40 kilowatts per square centimeter where the coating is applied to uncooled metal substrates.
