Optical Components
Optical Coatings, also called optical thin films, or optical thin film filters, are thin films of refractive materials deposited on the interfaces of the substrates of optical components and elements. Optical coating, composed of one single layer or multiple layers of thin films, modifies the interaction between light and surfaces and improves the transmission, reflection, and absorption in order to enhance the overall efficiencies of optical systems or alter the polarization state of lights. Typically, the coatings are adhered to the surface of optics using physical vapor deposition (PVD).
Hangzhou Shalom EO’s optical coatings cater to requirements of various operation wavelengths spanning from deep-ultraviolet (DUV), UV, VIS, to IR spectrum. Whether oriented to provide maximized optical transmissions and high reflections or to control the spectral compositions and characteristics of light, Shalom EO is capable of customizing optical coatings that reach your ideal expectations and fit your budget. The diverse types of optical coatings that we provide, including anti-reflection coatings, high-reflection dielectric coatings, metallic HR coatings, optical filter coatings, and beamsplitter coatings can be applied to an extensive range of optical components and laser optics, such as optical windows, optical lenses, optical mirrors, optical filters, polarizers, laser mirrors and lenses, nonlinear crystals, and laser crystals, etc.
Optical coatings in the general term can be divided into dielectric coatings and metallic coatings. Dielectric optical coatings are refractive thin films made of dielectric materials deposited on the substrate utilizing interference effects to achieve specific optical characteristics. Dielectric optical coatings can be composed of one single layer of thin film, as in the simplest case, to hundreds of alternating layers of thin films of different refractive indices to cancel the reflected waves from different optical interfaces via destructive interference or to maximize Fresnel reflection's constructive interference. The thickness of each film can range from a few tens of nanometers to a few hundred nanometers, where the thicknesses are fine-tuned to cooperate with the refractive indices of the coating materials to realize the flexible manipulation of interference. Metallic coatings are often applied as high reflection (HR) coatings on optical mirrors. Metallic HR coatings, although exhibiting higher fundamental absorption of the incident light, which leads to limited reflectivities, have the advantages of superior broadband reflection, and slight wavelength dependence due to the complex index of refraction present. Metallic mirror coatings are cost-effective and versatile attributing to their simple manufacturing process. Metallic coatings are delicate and prone to contamination, oxidation, and subsequent degradation, therefore enhanced metallic coatings and protected metallic coatings are manufactured to preserve the metallic coatings and increase their reflectance.
Shalom EO supplies a series of specialized coatings, including:
Anti Reflection (AR) Coatings: Anti-Reflection, or Anti-reflective (AR) coatings are optical coatings, often made of oxides, that minimize reflection, maximize transmission, and avoid ghost images. With AR coatings, the loss due to reflectivities can be effectively reduced, and if there are multiple optical components, the total energy efficiencies could be enhanced significantly with the AR coatings. We provide various AR coatings, including Broadband AR (BBAR) Coatings that offer optimized optical transmission across a wavelength range of interest, Dual/Multiple Wavelength AR Coatings that transmit two or multiple specific wavelengths, and Laser Line V-Coatings with V-shaped transmission curves designed for maximizing transmission of a narrow bandwidth around the center laser wavelengths.
High Reflective (HR) Dielectric Coatings: High Reflective (HR) Coatings are designed to provide high reflectance with minimal loss. Dielectric mirror coatings consist of alternating layers of thin films of different materials, one with a high index and one with a low index. Our HR dielectric coatings are suitable for applications requiring strong reflectivities at specific wavelengths, ideal as mirror coatings and other coating applications.
Metallic Mirror Coatings: We also offer metallic high-reflection coatings made of materials such as aluminum (Al), silver (Ag), and gold (Au) for optical mirrors. These coatings are available in protected or enhanced versions to ensure durable performance and better reflectivities of our metallic mirror coatings. Metal mirror coatings are sometimes excellent for ultra-short pulsed lasers where very broad bandwidth is required. The aluminum mirror coatings and UV enhanced aluminum coatings are cost-effective options for ultra-violet applications, the silver HR coatings are suitable for visible to infrared spectral range, while the gold high-reflective coatings provide excellent reflectivities for NIR to IR wavelength range.
Optical Filter Coatings: Optical filter coatings are optical coatings purposed to manipulate the spectral characteristics of light. Shalom EO offers a wide selection of optical filter coatings, including bandpass filter coatings, long pass/short pass coatings, optical notch filter coatings, and laser line filter coatings that are used for isolation of the wanted spectral bands.
High Power and Ultrafast Optical Coatings: Shalom EO provides optical coatings with elevated laser induced damage threshold (LIDT) for high power applications. Ultrafast optical coatings including ultrafast-enhanced silver coatings, low GDD dielectric coatings, and chirped mirror coatings for ultrafast pulsed lasers are also available.
Beamsplitter Coatings and Dichroic Coatings: The beamsplitter and dichroic coatings enable flexible separation of light into the wanted ratio. We can provide both polarizing and non-polarizing beamsplitter coatings High extinction ratios and high power laser grade beamsplitter coatings are available.
At Shalom EO, we use the advanced Ion Assisted Electron Beam Deposition (IAD e-beam) technique in our class 1000 clean room in-house coating workshop. The design and fabrication of optical coatings are a delicate process that involves the mindful exploitation of the material properties and the microstructures. For example, when customizing dielectric optical coatings, the thicknesses of the layers of the thin films are optimized, using modeling software, to realize the sophisticated manipulation of the constructive and destructive interference effects. Before the coating process starts, all the substrates are cleaned in our cleaning workshop with ultrasonic cleaning machines to remove particulate residue from the substrates.
Our IAD e-beam coating process combines the evaporation of target materials via electron beam with ion assistance, so that optical coatings can be formed at lower temperatures, meanwhile the ion bombardment improves coating densities, reducing the chances of spectral shifts under different environmental conditions. Our leading-edge IAD e-beam coating machines, such as the SHINCRON MIC-1350TBN, ensure that each coating meets the highest standards of performance, endurance, and precision.
Shalom EO maintains strict quality control standards throughout the coating process. From in-process control to final optical inspection, we ensure that the specification of optical coating meets the required specifications. Our state-of-the-art metrological equipment, including：
PerkinElmer Lambda 1050+ spectrometer, Ultrafast Innovations GOBI white light interferometer, etc., enable precise measurements. Critical technical parameters and individual test reports, such as transmission curves of optical coatings, are provided for our customers.
We also work with laboratories to obtain authentic results for the laser induced damage threshold (LIDT) to ensure that the damage resistance of the optical coatings adheres to the given specification. You can also click here to view a blog in our resource sector to learn about laser-induced damage threshold.
