Coating Technology & Design
Through continued investment in emerging technologies, Omega Optical introduces Dual Magnetron Reactive Sputtering (DMR Sputtering) to its portfolio of deposition methods. DMR Sputtering utilizes a proprietary plasma/ion, reactive, dual magnetron process, employing the latest advancements in programmable logic controls. Unlike traditional, time-consuming sputtering processes, including Ion Beam Sputtering (IBS), DC Magnetron, and Reactive Ion Plating (RIP), Omega's instrumentation is unmatched in process speed, completing depositions at significantly higher rates. The result of this high velocity fabrication, combined with state-of-the-art monitoring capable of in-process self-correction, yields a cost-effective finished product with exceptional uniformity and spectral discrimination.
A Word About Deposition Technology:
DMR Sputtering represents an important part of Omega's deposition portfolio. While used in applications requiring the most stringent spectral discrimination, it is important to remember that every unique optical configuration benefits from the proper choice of coating technology. Considerations such as image quality, system sensitivity, spectral isolation, and most importantly, cost, are all factors when choosing a filter. Often times, consultation at the initial stages of R&D greatly influences the proper choice of coating technology allowing a system to achieve the highest level of performance.
- Transmission in excess of 98%
- Low loss / ultra-low scatter coatings
- Durable, shift-free, environmentally stable surface coatings
- Full batch uniformity
- Theoretical models match spectral results of finished product
- High velocity manufacturing equals cost savings
- High laser damage threshold capability
- Large capacity sputtering instruments
- Sizes from 3mm to 200mm
- 1mm – 50mm thickness
- 250nm - 1700nm spectral coating range
QuantaMAX™ – for high performance interference filters
Outstanding spectral characteristics on a wide variety of substrate materials utilizing our state-of-the-art deposition technology, Dual Magnetron Reactive Sputtering (DMRS).
For today's most sensitive instruments, QuantaMAX™ optical coatings provide exceptional throughput. As seen in Figure 1, a standard 510-560 interference filter achieves transmission in excess of 97%. Combined with deep out of band attenuation, QuantaMAX™ optical coatings make every photon count.
For many applications, the out of band blocking at the detector is as important as the overall transmission. Figure 2 shows the out of band blocking from 300-1000nm and the optical density average of > 6.0. A ﬁlter with these characteristics operating in a system with an ideal light source and detector could be expected to have a signal/noise ratio of exceeding 10,000:1, while collecting all available signal.
Lot to Lot Reproducibility
With the Dual Magnetron Reactive Sputtering (DMRS) process, QuantaMAX™ optical coatings employ the latest methods in optical thin-ﬁlm design and deposition control. Utilizing the DMRS technology we achieve very precise individual layer thickness, along with forward and backward "proof-reading" of layer execution, leading to a high degree of predictability and reproducibility lot-to-lot. As depicted in Figure 3, the edge of the 650-670 bandpass ﬁlter varies only 1 nm in either the cut-on or cut-off edges across a sampling of 5 individual deposition lots.
Minimized Transmission Band Distortion
The ability to precisely deposit a layer of coating material of optimized optical thicknesses in a stable and highly reproducible manner throughout the deposition cycle provides excellent transmission characteristics with minimal pass-band rippling. Figure 4 and 5 show the typical performance of long-pass and short-pass interference ﬁlters.
Alpha Technology is the culmination of Omega's ongoing research and development regarding filter design and deposition techniques. Employing a proprietary method of controlling the coating process, this technology yields filters with exceptionally high signal-to-noise, as well as, steep transition slopes suitable for the most demanding applications. With Alpha Technology, optical systems achieve the highest level of spectral discrimination – images are brighter, contrast is enhanced and instruments perform to the limits of detection. Whenever an optical design demands the utmost level of precision, Alpha Technology is the obvious choice.
- Extremely sharp transitions from stopband to passband
- Precise, repeatable location of cut-on/cut-off wavelengths, tolerances within +/-0.01 to +/-0.005 of the edge 0.3OD - wavelength (50%)
- Transmission 85% avg., 80% minimum, up to 8% gain with anti-reflection coatings
- Tightly controlled ripple at cut-on
- Nearly uniform transmittance across the passband
- Exceptional attenuation of out-of-band signal
- Single surface coatings suitable for PMT and silicon detectors
- Optical quality transmitted wavefront
- Longpass, shortpass and bandpass spectral profiles
5-Decade Slope Factor:
Slope factor is a measure by which the sharpness of transition between attenuation and transmission is achieved. The industry standard is a 1-Decade slope factor measured between 80% and 10% transmission. Omega's Alpha Technology raises the bar by using a 5-Decade slope factor defined as:
Where λ OD5 is the wavelength at which an optical density of 5 is achieved (.001% transmission). Note that optical density of 0.3 is equivalent to 50% transmission.
Typical industry longpass filters display a 5% 1-Decade slope factor. Alpha Technology produces slope factors 5-50 times steeper and controls these edges to the following values at a 5-Decade slope factor: 1% Epsilon, 3% Gamma, and 5% Beta.
Alpha Epsilon – 1% 5-Decade Slope Factor
A superior filter for Raman and other demanding applications requiring superior spectral discrimination. These filters match the performance of a holographic Super Notch in edge steepness and depth of blocking.
Alpha Gamma – 3% 5-Decade Slope Factor
Steep edges, broader transmission and blocking regions with the same edge precision and smooth passband provided by the Alpha Epsilon design. Ideal for most fluorescent applications.
Alpha Beta – 5% 5-Decade Slope Factor
For less demanding applications and a better value than catalog filters. Much sharper edge precision than competitive long/shortpass filters.
Free Spectral Range and Blocking:
Longpass filters have a stopband from deep UV to cut-on edge and a passband from cut-on edge to 2500nm. Blocking performance is measurable to >/=OD5 minimum and >/=OD20 (in theory) for Alpha Epsilon.
Shortpass filters have a stopband from cut-off edge to the limits of a PMT or CCD detector sensitivity and a transmission band from cut-off to 1.3 x cut-off or 400nm.
SpectraPlus™ coating technology is the deposition of multiple layers of thin film coatings on glass and acrylic lenses for the enhancement of viewing color images to address two primary areas, color imaging systems as well as applications where the eye is the detector. The coating allows transmission of three bands of pure color—red, green, and blue—while blocking those intermediate wavelengths that distort the perception or recording of color. It also eliminates wavelengths in the ultraviolet and near infrared, which are detrimental to an accurate color rendering and visual record. This coating is generally applied to depict an accurate hue, enhanced saturation, increased color signal-to-noise, and a resulting improved Modulation Transfer Function (MTF).
Omega Optical has developed two unique products, Depth Defining® and Color Max™, using the SpectraPlus™ viewing enhancement coating.
Coatings such as photochromics, anti-scratch, or hydrophobic can be added to produce high performing products worldwide.
Applications of the coating technology and products where vision is critical:
- For Digital Imaging Systems
- Commercial Printing Industry: Pre-press Scanners
- Machine Vision Industry: Camera and Lens Systems
- Office and Home Small Equipment Industry: Desktop Scanners, Color Copiers, Digital Copiers
- Photography/Video/Film Industry: Video & Digital Cameras and Lenses, Photo Scanners
- Remote Sensing: Camera Systems
- For Human Eye and Photographic Film Detection
- Sports Eyewear Industry: Sunglasses, Ski Goggles, Active Sports Glasses
- Lighting Industry: Medical and Dental Lights, Bulb and Reflector coatings
- Photography/Video/Film Industry: Camera Lens, Video, Film and Slide Projectors, Color and Black & White Film Printers, Enlarger Lens
- Sports Optics Industry: Binoculars and spotting scopes, Rifle Scopes
SpectraPLUS™ is protected by U.S. patent #5,646,781.
Depth Defining & ColorMax Filters
Depth Defining® series is an entirely new approach to displaying and viewing an image with an X and Y impression as well as a clear Z element. The ultra-complex spectral function divides the visible into two visually identical white mixtures, which are mutually exclusive.
The left and right viewing eye see distinct images that have been projected spatially or temporally independent. The result is an image with depth that the viewer can experience with clarity.
ColorMAX™ series is intended for spectral refinement with the intended purpose of improving color rendition through saturation and hue. Curved lenses are coated with a complex multi-layer coating that removes harmful UV rays, as well as IR. These coatings further eliminate the colors of light that stimulate multiple cones that result in color confusion. A common use for this technology is eyewear that forces all colors to explode from their background, but it can also be applied into a variety of applications.
We offer two ColorMAX™ filters with SpectraPLUS™ coatings; XB29 is optimized for digital imaging sensors and XB30 is optimized for the human eye and film. All filters are finished to the highest imaging quality standards and are available in stock and custom sizes.