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What is an Optical Notch Filter and What Do They Do?
July 5, 2022 4:42 pm Leave a Comment
Optical notch filters are devices designed to attenuate light within a specific wavelength range to a very low level while transmitting most wavelengths with little intensity loss. Other names for optical notch filters include band-rejection or band-stop filters.

They do the opposite of bandpass filters, a different type of filter that provides high out-of-band rejection and high in-band transmission, thus only allowing light transmission within a small wavelength range.

The tilt of the optical notch filter with respect to the incident light is its angle of incidence (AOI). If the incident light is normal to a notch filter, the AOI is 0°. Transmission depends on the AOI for all-dielectric stack filters. As the AOI increases, the central wavelength of the hindering region shifts to shorter wavelengths.

Optical Notch Filter Frequencies

Optical notch filters reject or block a specific wavelength region while transmitting on either side of the blocking region. Traditional notch filters offer up to 85% peak transmission.

Optical Density

Optical density (OD) refers to the amount of energy that an optical notch filter rejects or blocks. If the optical density value is high, the filter blocks more energy, resulting in low transmission. If the optical density value is low, the filter rejects less energy, resulting in high transmission.

Optical density is crucial in establishing the strength of a filter. Its measurements can help in measuring the growth of a microorganism’s culture, biomass concentration, and other analytical techniques used in the life sciences.

You can find notch filters of different bandwidths in the market, but the most common types are narrowband filters.

Traditional band-stop filters also come with harmonic rejection bands. However, you need to worry about these only where wide pass bands are necessary. Although it is possible to adjust coating designs to remove harmonic rejection bands where they are not required, such coatings are more sophisticated and need to be thicker.

Optical Notch Filter Applications

Optical notch filters have many applications where there is a need to transmit some wavelengths while reflecting or blocking others.

These include:
- Spectroscopy: Spectroscopy uses optical notch filters to evaluate the rotational and vibrational characteristics of molecular and crystal structures. Notch filters also assist scientists in evaluating the properties of molecules by isolating the specific wavelengths of interest. This feature helps in evaluating forensics evidence, identification of an unknown substance, drug detection, and evaluation of how molecular structures respond to certain environments.
- Optical communication systems: These systems use optical notch filters to deter any distortions that can get into the light pathway. For instance, they are useful for laser safety applications such as laser eye protection, whereby safety glasses have a coating to block potentially harmful wavelengths.
- Analytical measurements: Notch filters, through optical density measurements, help measure analytical techniques such as the growth of micro-cultures and biomass concentration.
- Life Sciences: Optical notch filters are crucial in life science applications such as confocal or multi-photon microscopy, Raman spectroscopy, and more.
- Multi-band rejection: OD 4 or OD 6 optical notch filters have a multi-notch capability. Notch filters with such capabilities are useful in applications that require the rejection of the multiple narrow bands without using a multi-filter setup. OD 4 filters are great for applications that require narrow rejection bands of ±2.5% of the center wavelength and more than 99% reflection of the designated laser wavelength. On the other hand, OD 6 filters are useful for applications that require deep blocking of a narrow wavelength range while providing broad transmission of the other wavelengths. The applications include integration into life science systems, laser-based Raman spectroscopy, and fluorescence.
Contact Evaporated Coatings for Your Optical Notch Filter Projects

Optical notch Filters selectively block a section of the spectrum while allowing the transmission of all other wavelengths. They are useful where there is a need to transmit some wavelengths while reflecting or blocking others, e.g., in spectroscopy, optical communication, and life-science applications.

At Evaporated Coatings, Inc., we are the best in helping our customers implement optical notch filter projects for narrowband, broadband and multiband applications. Our goal is to give our customers a product that meets or exceeds their specifications and all other compliance requirements. Also, we consistently strive to enhance customer satisfaction by implementing an effective quality management system, recruiting a knowledgeable team, applying risk-based thinking, and continual improvement.

Contact us for all your optical notch filter project needs or request a quote to get started.
Why Notch Filters Are Essential in The Coating Industry
January 24, 2022 4:45 pm Leave a Comment
Notch filters, otherwise known as band-rejection or band-stop filters, are a type of optical filter designed to selectively reject a wavelength band and transmit at both longer and shorter wavelengths. Notch filters are often used throughout the coating industry to create components for various technological and scientific applications such as raman spectroscopy, laser-based fluorescence instrumentation, protection from laser radiation, and more.

Notch Filters in the Coating Industry

Ion-assisted electron-beam deposition technologies are the most widely used in coating manufacturing. This method features numerous advantages, such as a high deposition rate and excellent stress quality. To create notch filters using this deposition technique, it’s important to consider layer thickness constraints. If the layer thicknesses are not too thick or too thin, it allows for more accurate control of the index of refraction and thickness.

Notch Filter Applications

Notch filters are used across various applications that require the transmission of some wavelengths while others need to be reflected or blocked. For example, many types of spectroscopy use this type of filter to assess the rotational and vibrational characteristics of molecular and crystal structures. This is especially beneficial in assessing how molecular structures react in specific environments as well as identifying unknown substances, detecting drugs, and analyzing forensic evidence.

A crucial factor in determining a filter’s strength is optical density. These measurements help in the growth of a microorganism culture, measuring biomass concentration, and other analytical processes within the life science industry.

Another application of notch filters is with optical communications systems. These systems use notch filters to block any distortion that happens in a light pathway. Notch filters are also used frequently for laser safety applications, including laser eye protection. Safety glasses are designed and coated to reject harmful laser wavelengths.

Most notch filters offer up to 85% peak transmission. Notch filter designs are available for deposition onto polymers, fiber ends, semiconductor materials, crystals, glass, and other temperature sensitive materials.

Notch Filter Coatings from Evaporated Coatings

Notch coatings are effective in transmitting some wavelengths while blocking others, making them suitable for a range of optical applications throughout various industries. At Evaporated Coatings, we manufacture notch filters with up to three rejection bands. Our design team can work with you to determine your specific requirements including incident medium, angle of incidence, optical density, steepness of cut on and cut off transitions, and transmission wavelength range. As experts in optical coatings, we can deliver a notch filter solution that meets the needs of your unique application.

To learn more about our capabilities, or to get started on your custom notch filter solution, contact the experts at Evaporated Coatings today.
What Are Neutral Density Filters?
4:10 pm Leave a Comment
A neutral density (ND) filter is a darkened glass affixed to a lens. This filter between the subject and the imaging tool reduces light wavelengths so that colors are not overexposed. ND filters only affect light, not color reproduction, sharpness, or contrast. We’ll explain in more detail how ND filters work, the various types of ND filters, and filter solutions by Evaporated Coatings.

How Do Neutral Density Filters Work?

Filtering the intensity of the colors of light that reach the imaging sensor allows operators better control over shutter speed and aperture selection. Thus, ND filters allow users to capture clear images in intense lighting conditions, yielding results that cannot be created through post-production editing.

Types of ND Filters

Fixed ND filters, also called solid ND filters, have a coating equally distributed across the filter frame, producing a predetermined filter density. You can choose how dense you want the fixed ND filter to be depending on your imaging conditions. For instance, using a lighter density 3-stop filter allows you to set the shutter speed three times slower.

Variable ND filters feature two polarized filters working together, where one blocks a set amount of light while the other rotates so that the user can control the total amount of light let in at any given time.

ND filters come in a wide range of polarization levels, from 2x, 4x, 8x, all the way up to 8192x. Each increase in multiplier corresponds to one f-stop, or one EV of light difference registered by the imaging tool. The polarization levels represent optical density (OD) and translate to different percentages of the original lens opening. For example, 2x means a 50% lens opening and 0.3 OD, 4x means a 25% opening and 0.6 OD, and 8x represents a 12.5% opening and 0.9 OD.

Neutral Density Filters from Evaporated Coatings

ND filters allow you to control how much light filters through your imaging tool. They enable better control over shutter speed and aperture settings, so you can create clearer images without affecting contrast, sharpness, or color.

Evaporated Coatings, Inc. has been a leader in optical coatings for more than 60 years. We have maintained this position by innovating vacuum deposition technology and thin film processes. From design to preparation to coating, ECI brings technical knowledge, competitive pricing, and customized service to every client’s optical solution. Our product line covers a variety of optical coatings and substrates. For more information about our products and capabilities, contact us today.
What Are Thin-Film Optical Filters?
January 20, 2022 10:11 pm Leave a Comment
Usually attached to a substrate like glass, thin-film optical filters are layers of materials with optical properties. These filters change the direction of light as it passes through them, creating internal interferences. Filters can be specially designed to transmit, reflect, or block light in any wavelength between ultraviolet (UV) and infrared (IR).

Thin-film optical filters can be used for many optical applications, including astronomy, solar imaging, fluorescence microscopy, telecommunications, and remote sensing. This blog will discuss the mechanics of thin-film optical filters and their five main types.

How Thin-Film Optical Filters Work

To create a thin-film optical filter, we deposit the necessary coating onto the optical glass with extreme precision. One deposition method is ion-assisted e-beam evaporation. During this process, a beam of ions is directed at the substrate at the same time that the evaporated materials are being deposited onto the substrate. The ions contain energy that is released into the evaporative atoms of the materials, creating a thin film.

Physical vapor deposition creates thin films by vaporizing solid material inside a vacuum and then depositing it onto the substrate. This type of deposition results in durable, scratch-resistant coatings. They can also withstand high temperatures.

The specific thickness and number of coatings will affect the wavelength of light that passes through the filter. These methods, along with others, create durable coatings to achieve the intended optical effects.

Types of Thin-Film Optical Filters

There are five main types of optical filters.
1. Bandpass Filters. These filters transmit certain wavelengths and block out the surrounding light.
2. Notch Filters. This type of filter blocks out a variety of wavelengths and transmits light on either side.
3. Shortpass Edge Filters. Short wavelengths are transmitted through this filter, and longer wavelengths are blocked.
4. Longpass Edge Filters. Long wavelengths are transmitted through this filter, while short wavelengths are blocked.
5. Dichroic Filters. A dichroic filter reflects certain wavelengths while others pass through it.
The first four filters are intended for use at 0° or other small angles of incidence. Dichroic filters are best used at 45° or less.

Some of these types can be combined to create multiband filters. We can also create custom filters that have a different spectral shape than those listed above.

Evaporated Coatings Inc.’s Thin-Film Optical Filters

Evaporated Coatings Inc. has over 60 years of experience producing high-precision optical coatings. We have the expertise necessary to design and create thin-film optical filters that will solve your industry-specific problems. We are dedicated to staying up-to-date in the optical filter industry, as we develop our own thin-film designs and processes using advanced deposition methods.

Our experienced engineering staff handles the entire process: design, preparation, and coating. We deliver personalized service to customers in the United States and around the world. Contact us to find out how we can meet your specific thin-film optical filter requirements.
Considerations for Selecting AR Coatings
August 11, 2021 3:21 pm Leave a Comment
Anti-reflective (AR) coatings are optical coatings that decrease the amount of light reflected off a surface. Commonly applied to lenses, mirrors, or glass barriers, AR coatings are designed to maximize the throughput of light, while reducing hazards caused by reflections. This ability makes AR coatings an ideal solution for optical instruments, imaging devices, cameras, telescopes, eyeglasses, binoculars, and more.

To determine whether AR coatings are the best fit your needs, there are various factors to consider, including the number of optical elements, the substrate, and the application.

Number of Optical Elements

Uncoated reflective glass substrates can interfere with the passage of light through an optical system. Due to Fresnel reflection, 4% of transmitted light is lost at each interface of an uncoated glass substrate, resulting in only 92% total transmission of incident light. The reduced throughput and reflected light can simultaneously cause damage and reduce performance.

AR coatings increase throughput and stop the reflected light from causing damage. They are especially useful for systems containing multiple optical elements, as they allow for more efficient use of light.

Substrate

The type of substrate will also play a role in determining whether an AR coating will be the most effective solution. At Evaporated Coatings, we offer AR coatings for the following substrates:

Glass

Glass AR coatings can target any wavelength spectrum ranging from 200nm to 2500nm. To ensure maximum transmission through a system, clients can specify their incident medium, wavelength range, angle of incidence, polarization needs, and the substrate index of refraction. Glass is frequently used in laser systems, which require AR coatings that can meet or exceed Laser Damage Threshold (LDT) minimums for the system.

Plastic and Molded Polymer

Many plastics and molded polymer substrates are vulnerable to heat damage, so they need particular AR coating processes in which the temperature doesn’t exceed 50°C. Low-temperature AR coatings can be applied to a wide variety of substrates, such as Kapton, polycarbonates, acrylics, and more. However, they typically operate within a slightly narrower range of frequency, from 300nm to 2000nm.

Fiber Optics

Fiber optic materials, including fiber arrays and ends, laser diodes, lenses, and more, utilize AR coatings to increase light transmission. These materials require a low-temperature anti-reflective coating process that reduces the risk of outgassing. To meet the needs of various applications, these AR coatings come in many designs, including L-Band, C-Band, dual wavelength, and more.

Crystals, Semiconductors, and Garnet

For these substrates, AR coatings are deposited with high energy, producing dense films with superior surface qualities and low optical loss. These AR coatings ensure a high resistance to laser damage, excellent surface qualities, and minimal spectral shift due to moisture exposure. AR coatings can be customized based on the sensitivity of the crystals, wafers, or semiconductor materials.

Application

AR coatings solve a variety of issues across a diverse range of industries, including photography, optometry, solar energy, and more. When determining whether AR coatings are the right solution for your needs, it’s important to consider your intended application.

Common applications that benefit from AR coatings include:
- Displays. AR coatings on displays and screens allow for greater optical performance by minimizing glare and reflection. When outside light hits a screen, it causes glare. AR coatings can solve this problem.
- Camera Systems. Camera systems use AR coatings to reduce unwanted reflections and glare when used for imaging and telecommunications.
Types of AR Coatings

If you determine that your application can benefit from an AR coating, it is crucial to understand the different types to ensure you choose the best fit. There are many types of AR coatings available, including:
- Single. Single magnesium fluoride coatings have an excellent refractive index for use on glasses, cameras, and other lenses that interact with visible light. The coating can also resist abrasion and humidity.
- Multi. Multi coatings consist of several thin films, each of which has different refraction indices. This type of AR coating maximizes transmission.
- Broadband. Broadband coatings are specifically designed to improve transmission over a wider waveband. As a result, this type of coating is much more versatile.
- “V”. V coatings specifically target a narrow wavelength range, and they are typically used in laser systems. The coating has a high refractive index for all wavelengths outside the designated range.
To learn even more about AR coating considerations, download our eBook, called Key Principles & Design Considerations for Anti-Reflection Coatings, which expands on this information and more.

AR Coatings From Evaporated Coatings

There are many factors to consider when determining whether an AR coating is right for your needs. At Evaporated Coatings, we work with you to identify and design high-quality AR coatings catered to your specific application. Learn more about our anti-reflective coatings or request a quote today to start your order.
What’s the Difference Between Anti-Reflective and Anti-Glare?
May 16, 2021 6:07 pm Leave a Comment
“Anti-reflective” and “anti-glare” are common terms related to coating, but they are each distinct and provide different benefits. Depending on a particular application, an anti-reflective or anti-glare coating may be appropriate to use. Knowing what separates these two concepts can help determine which is best to use for a given coating.

Here, we’ll review the differences between anti-reflective and anti-glare coatings and the common applications for each.

Key Differences Between Anti-Reflective vs. Anti-Glare

When deciding whether to use anti-glare vs. anti-reflective coating, there are a few distinct differences to keep in mind.

Anti-Reflective

Anti-reflective coatings feature:
- The ability to decrease power output for LED lighting and displays, making it suitable for many types of ambient lighting
- High transmission with reduced reflectance
- Reduced ghost images
- Increased brightness and glass transmission
- Enhanced contrast to create clear, sharp text and graphics
- The ability to customize it for precise light wavelengths
Anti-Glare

For other applications, features of anti-glare coatings include:
- Suitability with high-ambient or outdoor light applications with external sources of reflection
- High resolution with low reflection, along with an anti-newton ring and high durability
- Acid etching on one or two glass surfaces
- Dispersal of light on glass surface as light hits it
- Maintains low reflection when exposed to oily fingerprints, unlike untreated surfaces or glass with anti-reflective coating
Anti-Reflective Coated Glass Applications

Anti-reflective coatings are suitable for many applications requiring optimal image quality. This is because they consist of a single or multiple layers, which are intended to create destructive interference in reflected light. In turn, this permits the maximum level of light transmission without sacrificing image quality.

There are several applications that are compatible with anti-reflective coated glass, including:
- LCD Displays
- LED Lighting Optics
- Telecommunications
- Front Panel Displays
Anti-Glare Coated Glass Applications

Like anti-reflective coatings, anti-glare coatings can disperse reflected light, enabling users to focus on a transmitted image, making it suitable for a variety of applications requiring high-quality images. However, unlike anti-reflective glass, anti-glare coated glass is also ideal for more interactive technology that requires users to touch screens with their hands, as it prevents oil from decreasing picture quality. Additionally, anti-glare glass features varying etching and quality levels, ranging from 60 to 130 gloss units for optimizing display or picture frame quality. A low gloss level of around 60 units will lead to a more diffuse panel surface, significantly reducing glare. On the other hand, a higher diffusion level can also decrease panel resolution.

Some specific applications for anti-glare coatings include:
- Computer Screens
- LCD Displays
- Electronic Displays
- Medical Instrumentation
- Touch Screens
An Introduction to the Different Types of Optical Filters
April 26, 2021 1:58 pm Leave a Comment
Optical filters are passive optical devices that consist of specialized optical coatings applied onto a substrate. The coatings modify the refractive index of the substrate, enabling them to reflect, transmit, or absorb incoming light depending on its wavelength. This quality is useful for various optical tools and systems, such as chemical analysis units and microscopes.

Optical filters are available in many variations, each of which possesses distinct characteristics that make it suitable for particular applications. Below, we provide an overview of some of the different types available.

Absorptive Filters

Absorptive filters have coatings made from organic and inorganic materials. These materials enable the filter to absorb the undesirable wavelengths and transmit the desirable wavelengths. This design ensures that no energy is reflected back toward the light source.

Dichroic Filters

In contrast to absorptive filters, dichroic filters—also called thin-film filters or interference filters—have coatings that enable them to reflect the undesirable wavelengths and transmit the desirable wavelengths. The thickness and properties of the coatings determine which wavelengths are reflected and which wavelengths are transmitted. These types of optical filters are highly accurate, enabling users to target a small range of wavelengths.

Notch Filters

Notch filters—also called band-stop filters or band-reject filters—are designed to block a specific frequency band (i.e., the stopband frequency range). Any wavelengths above or below this range are allowed to pass through freely. These types of optical filters are ideal for applications involving the combination of two or more signals since they can help isolate out interference.

Bandpass Filters

In contrast to notch filters, bandpass filters are designed to block every frequency except for a small range. They are a combination of shortpass filters and longpass filters—filtering out any wavelengths that are too short or too long. This cutoff range can be lengthened or narrowed by adjusting the number of layers in the filter.

Shortpass Filters

Shortpass filters are designed to transmit wavelengths below a set length determined by the optical coating and substrate. Any wavelengths that are longer than that point are blocked. These types of optical filters are commonly used to isolate specific higher regions of a broad spectrum and in conjunction with longpass filters for bandpass filtration applications. Typical applications include chemical analysis systems.

Longpass Filters

Longpass filters are designed to transmit wavelengths above a set length determined by the optical coating and substrate. Any wavelengths that are shorter than that point are blocked. Typical applications include fluorescent spectroscopy systems. Additionally, they are commonly used in conjunction with shortpass filters for bandpass filtration applications.

Thin-Film Optical Filter Solutions From Evaporated Coatings, Inc.

Want to learn more about optical filters and how to choose the right one for your optical needs? Turn to the experts at Evaporated Coatings! We specialize in the supply of high-precision optical coatings. By helping customers select the right coating and applying it to their substrates, we can make custom optical filters for virtually any application.

Check out our custom optical filters page to learn more about our thin-film coating capabilities. To discuss your optical filter requirements with one of our team members, contact us today.
Design Guide for Thin Film Coatings
April 14, 2021 9:19 am Leave a Comment
Thin film coatings, such as antireflective (AR) coatings, are made from various materials, such as metals, oxides, and compounds, and are deposited in layers onto a substrate. Thin film coatings can be deposited in both single and multiple layers, and the configuration you choose determines how it will manipulate different wavelengths of light.

Thin film coatings have many different characteristics, which are used to improve or alter some element of the substrate’s capabilities. The design and configuration of thin film coatings heavily depend on performance requirements, and the proper design is crucial to the functionality and overall success of your application.

Single Layer AR Coatings

Single-layer AR coatings can have different refractive indices depending on the material. For example, single-layer AR coatings of magnesium-fluoride have a refractive index of 1.38. Applying the coating to a substrate with a 1.9 refractive index provides 0% reflection.

Single-layer AR coatings of magnesium-fluoride can be adjusted to perform with various wavelengths and typically prevent reflection of 550 nm lasers. Single-layer AR coatings are prevalent, but complex applications may require multi-layer AR coatings.

Double & Triple Layer AR Coatings

Two or more AR coating layers can overcome the limitations of a single layer AR coating. Combining high and low index coatings, such as 2.3 and 1.38 produces a narrow bandwidth and close to 0% reflection. Three-layer coatings create a broadband AR coating using two high and a single low index coating, such as 2.1 and 1.38.

Some substrates cannot achieve the necessary refractive index with a single coating. Multi-layer coatings allow manufacturers to use more available materials to block a more diverse range of incident angles and wavelengths. It is vital to consider the ideal materials when selecting a two or three-layer AR coating, as the refractive indexes available are limited and deposition is imperfect.

Design Considerations for Thin Film Coatings

When designing a configuration for thin film coatings, consider the following factors:
- Thin film coatings offer increased performance at lower angles of incidence.
- Longwave pass (LWP) filters allow for greater transmission and typically higher-performance than shortwave pass (SWP) filters. LWP filters enhance manufacturing tolerance and use more simple AR coatings.
- Designing a coating with a greater than 2:1 bandwidth ratio increases the difficulty. It requires more layers and increases the percentage of reflection, with a higher reflection penalty when coating 30° and 45° angles of incidence.
- For the most ideal design for manufacturing, consider materials that are 10nm or greater thickness.
- Specify only necessary coating requirements. Performance is most optimal when requirements are specific and there is not a wide range.
It is also necessary to consider the substrate texture. Substrates with lithography or etching require an AR coating with an approximate profile with a smaller height and width than the shortest wavelength.

Single wavelength coatings are typically easier to manufacture compared to multiple wavelength coatings. Specific materials must be chosen for each wavelength, increasing the cost and complexity, especially when transmitting long and short wavelengths.

Thin Film Coatings From Evaporated Coatings, Inc.

When designing thin film coatings, such as AR coatings, films can be deposited in single and multiple layers to suit various substrates and applications. There are essential considerations when designing a thin film coating that will offer the performance you expect. At Evaporated Coatings, Inc., we are a leader in thin film coatings with over 60 years of experience in optical coating solutions. We can work with you to design and deposit custom AR coatings based on the needs of your application.

For more information, or for help with your thin film coating design, contact us today. We also offer an eBook, called How to Determine Your Ideal Thin Film Coating Process, if you’d like to learn more about which thin film coating process might be right for you.
Applications of Optical Microscopes
March 15, 2021 3:11 pm Leave a Comment
Optical microscopy is a technique that allows the viewing of samples more closely using optical microscopes. It relies on light and one or more lenses to magnify samples. Optical microscopy is remarkably versatile, increasing the detail and contrast of a microscopic specimen. A range of applications rely on simple and complex microscopy techniques.

Fluorescence

Fluorescence microscopy is a type of optical microscopy that uses a fluorescent dye called fluorophores. When light hits the dye, it induces fluorescence rather than scattering or absorbing light, making tissue, cells, and proteins visible under a microscope. Fluorophores absorb energy from a specific wavelength known as the excitement range resulting in the energy’s re-emission in a wavelength known as the emission range.

Learn more about how we employ optical filters in fluorescence microscopy.

Phase Contrast

Click to expandPhase contrast is a form of optical microscopy that allows operators to view transparent specimens with enhanced contrast. Transparent samples, cells, and microorganisms are viewable in high-contrast without fixing or staining the samples. The technique allows viewers to see live specimens in their natural state.

Differential Interference Contrast

Differential interference contrast (DIC) introduces contrast to samples with minimal contrast using optical microscopy. It provides a near 3D appearance to the specimen, allowing viewers to see a contrasting image in high resolution. DIC uses infrared light for its long wavelengths, allowing the light to penetrate thick samples.

DIC creates a contrasting image when light passes through a polarizing filter and another polarized optical device. The polarized light passes through an objective-specific prism where the light beam is split and passes through a condenser. The condenser focuses the beams of light on specific points of the specimen.

The light beams pass through the specimen at various locations and various wavelengths. They move on to an objective lens that refocuses the beams on the rear of the focal plane. The nosepiece prism combines the beams, and the beam passes through the analyzer. The analyzer causes destructive and constructive interference, bringing the beams to the identical axis and plane. The light travels to the camera for the viewing of the DIC image.

Brightfield and Darkfield Illumination

Brightfield illumination presents a dark specimen on a bright background to create contrast. It is a simple technique that positions a light source below the sample. Light passes through the specimen to an objective lens and optical sensor. The darkness of the specimen increases with the specimen’s density. The more dense the sample is, the more pronounced the image will be.

Brightfield illumination is the result of these four key elements:
- Light Source
- Condenser Lens
- Objective Lens
- Eyepiece or Camera
Darkfield illumination creates a light specimen image on a dark background, contrasting the brightfield illumination technique. This technique enhances a specimen’s contrast without staining, allowing observation of living specimens.

Darkfield illumination begins with a light source that is obstructed by a dark field patch stop as it enters the microscope. The light is reduced to a ring where the condenser lens focuses it onto the sample. When the light hits the specimen, it transmits or scatters. The objective lens permits scattered light but blocks transmitted light with help from the dark illumination block.

Optical Microscopy Solutions From Evaporated Coatings

Optical microscopy improves specimen viewing by magnifying microscopic samples and enhancing their visibility with techniques and lenses. Fluorescence, phase contrast, brightfield illumination, darkfield illumination, and DIC allow optical microscopes to deliver a closer image in various applications.

At Evaporated Coatings, we specialize in high-quality optical coatings. We manufacture a range of optical filters, including excitement and emission filters for fluorescence microscopy. Our designers can help you find a cost-effective and high-performance solution, and our technicians use leading technology to manufacture the substrate and coatings you require. Contact us today to learn more about our high-quality optical coating solutions.
Ion Beam Sputtering
March 11, 2021 9:34 pm Leave a Comment
Ion Beam Sputtering Coating (IBS) uses an ion source to deposit or sputter a thin film onto your targeted material to create a dielectric film. Since an ion beam is mono-energetic and collimated, it creates a very precise control over the thickness of the film. Since an ion beam is mono-energetic and collimated, it creates very precise control over the thickness of the film.

A typical configuration of IBS systems includes the substrate, a target, and a gridded ion source, with the ion beam being focused on a target material, and a nearby substrate being the sputtered target material.

What Is Ion Beam Deposition?

IBS, otherwise known as ion beam deposition, is a process that deposits a thin film of dielectric or metallic material onto a substrate while allowing for extremely fine control over the coating thickness. During this process, an ion beam or source deposits, or sputters, material from a supply onto the workpiece in a dense, consistent pattern.

Ion beam deposition processes are uniquely advantageous because operators can control everything from the sputtering rate to the ionic energy and density. This allows for complete control of the microstructure and film stoichiometry of the deposited layer. For applications that demand precision, such as with semiconductors, IBS outperforms alternative sputtering processes like physical vapor deposition.

What Is Assisted Ion Beam Deposition?

Assisted ion beam deposition uses two simultaneous processes — IBS and ion implementation — to create an intermixed coating. This process allows for a fine degree of control and can form gradually thickening or thinning transitions between the film layer and the underlying substrate’s original surface layer. Assisted ion beam deposition also gives the deposited film a much stronger bond.

The Main Advantage of Ion Beam Sputtering Coatings

One of the advantages of IBS is the control you get over several parameters. These include ion current density, ion energy, and the angle of incidence to help with the control of film microstructure. This is the main advantage and difference of sputtering processes, which makes IBS a great choice for any challenging applications you may have.

Additional Benefits of IBS Coatings

IBS coatings are known for providing precision control and high-density deposition layers. Other benefits of this coating method include:
- High Energy Bonding. The IBS process provides enough kinetic energy to create a durable bond between the substrate’s surface and the coating.
- Uniformity. Sputtering is typically emitted from a larger target surface area, ensuring a more uniform application when compared to vacuum coating and other alternative methods.
- Versatility. IBS can provide a coating for nearly any material, even those with high melting points. This makes it an excellent choice for projects that require very particular coating properties.
Ion Beam Sputtering Coatings From Evaporated Coatings

At Evaporated Coatings, Inc., we specialize in providing high-quality optical coatings, AR coatings, depositions, and more. We work with each of our clients to select the right coating process based on each project’s budget, unique requirements, and intended applications. Contact us today to learn more about our design, preparation, and coating services, or visit this page to learn more about our IBS services.