White Papers

Next-Generation Thin-Film Optical Filters for Life Sciences

13NovNovember 13, 2015

Next-generation thin-film optical filters enhance excitation and emission in fluorescence imaging and detection systems.

Fluorescence based systems have revolutionized the way organisms, cells, and biomolecules are visualized and detected. However, challenges that are common in these instruments, such as bleedthrough, background autofluorescence, and poor signal-to-noise ratios (S/N), can reduce performance and lead to frustration.

Fortunately, performance and signal quality can be greatly improved by integrating next-generation thin-film optical filters into fluorescence based instruments. Because proper optical filtering boosts throughput and enables wide-scale blocking, it solves problems like backscatter and poor signal quality, resulting in bright, high-contrast images of the target molecules.

Because system performance greatly depends on filter quality, optical filters are arguably the most important component of any fluorescence based instrument. With that in mind, here are some important concepts that should be considered when selecting optical filters for a fluorescence based system. (more…)

Learning Center, White Papers

Ultra-Narrowband Optical Bandpass Filters with Large Format and Improved Temperature Stability

18SepSeptember 18, 2014

Michael Scobey, Peter Egerton, Rance Fortenberry, and Amber Czajkowski

Sophisticated monitor and deposition methods enable multi-cavity narrowband filters that push the envelope of performance.

Hard coated ultra-narrowband optical filters made using modern plasma processes offer much improved transmission, temperature stability and out of band blocking as compared to legacy soft coatings. These filters are used in optical systems as diverse as LIDAR (light detection and ranging), Doppler shift detection of plasma velocity, laser cleanup, chemical and gas sensing, as well as for cutting-edge astronomy and instrumentation applications. (more…)

Learning Center, White Papers

Advanced Plasma Deposition Improves Ultra Narrowband Optical Filters

14JanJanuary 14, 2014

Michael Scobey, Peter Egerton and Rance Fortenberry

Published in SPIE Optical Design & Engineering December 18th, 2013.

A novel computer-controlled deposition system for multicavity filters improves their spectral precision and contrast.

Narrowband filters are a critical technology for a variety of applications such as lidar (light detection and ranging), laser cleanup, chemical and gas sensing, instrumentation, and astronomy. The design principles are well known and relatively simple. All designs rely on stacked Fabry-Pérot resonant cavities with dielectric reflectors composed of layers a quarter of a wavelength thick, spaced apart by cavities multiple half-wavelengths across. Several cavity filters are used in combination to ‘square up’ the spectral wave shape, resulting in the transmitted light having a ‘flat-topped’ spectrum when compared with that from light passed through single-cavity filters, which has a sharp, peaked spectral shape. Such multicavity filters also have much steeper rejection responses than single-cavity filters: the less-steep spectral slopes of single-cavity filters can compromise signal-to-noise in narrowband detection. (more…)

Learning Center, White Papers

Precision Infrared Narrow Bandpass and Dual Bandpass Filters Featuring Low OH-Band Absorption

20JunJune 20, 2013

Alluxa Engineering Staff, June 2013

Alluxa’s new precision infrared bandpass and dual bandpass filter technology brings new levels of performance with higher transmissions, steeper slopes, and flatter pass bands than traditional evaporated coatings.

Alluxa’s new class of Infrared (IR) bandpass and dual band filters bring the precision of dielectric filters to the IR between 2 and 5 microns. They are manufactured with an advanced, plasma enhanced PVD process using durable, hard metal-oxide, and durable semiconductor front surface thin films. The films have excellent environmental stability. The OH (water) band at 2.7 microns shows loss below the measurement limit even after 10 days of harsh Mil-810G temperature and humidity cycling. (more…)

Learning Center, White Papers

Specifying Plasma Deposited Hard Coated Optical Thin Film Filters

13DecDecember 13, 2012

Alluxa Engineering Staff, December 2012

Due to their complex nature and diverse end-use applications, thin film optical filters have always been a challenge to specify. This paper defines the major types of filters and offers guidelines on how to specify key attributes, while also optimizing the cost.

Due to their complex nature and diverse end-use applications, thin film optical filters have always been a challenge to specify. This paper defines the major types of filters and offers guidelines on how to specify key attributes, while also optimizing the cost. The filter types discussed include

Band pass types of ultra-square high cavity count, ultra-narrow and soft coating replacements
Dichroic and Polychroic tilted beamsplitter filters

(more…)

Learning Center, White Papers

Thin Substrate, Dichroic and Polychroic Thin Film Filters Featuring Flatness Less Than Zero Point 1 Waves RMS

13DecDecember 13, 2012

Alluxa Engineering Staff, December 2012

Alluxa Introduces a New Line of Ultra-Flat Dichroic and Polychroic High Performance Thin Film Filters that Feature a Flatness of <0.1wave RMS Without the Need for Backside Compensation.

Alluxa is introducing a new line of thin substrate ultra-flat dichroics and polychroic filters for use in imaging applications that require flatness levels exceeding 0.1 waves RMS per inch. These filters are unique because they achieve flatness by eliminating the high stresses of as-deposited traditional ion-based coating process such as Ion Beam Sputtering (IBS) and Ion Assisted Deposition (IAD). Alluxa’s new technique uses a novel plasma coating process that produces low loss, fully dense dielectric films with essentially net zero stress on the primary coated side. This means that the coatings do not require industry standard backside compensation or the use of very thick and expensive substrates to assure flat surface figures. The backside is coated with a simple low cost and high performance Anti-Reflection (AR) coating. Alluxa has achieved flatness levels of <0.1 waves RMS at 632.8 nm per inch with substrates as thin as 0.5mm. (more…)

Learning Center, White Papers

Flat Top, Ultra-Narrow Bandpass Optical Filters Using Plasma Deposited Hard Oxide Coatings

09SepSeptember 9, 2012

Alluxa Engineering Staff, September 2012

Thin film optical filters with ultra-narrow bandwidth, high transmission and flat spectral profiles improve optical system performance for a variety of applications such as LIDAR, laser cleanup, and instrumentation.

Alluxa’s new class of ultra-narrow filters are designed for applications such as laser clean up, LIDAR, telecommunications and instrumentation and offer the narrowest and “squarest” filter profiles in the visible and NIR as well as transmission levels that approach 100%. They are manufactured with Alluxa’s proprietary advanced plasma enhanced PVD process using durable, hard metal-oxide, front surface thin films and are virtually impervious to environmental effects. (more…)

Learning Center, White Papers

New Metrology Techniques for Advanced Thin Film Optical Filters

21JunJune 21, 2012

Alluxa Engineering Staff, June 2012

Improvements in optical filter performance require improvements in optical filter measurement techniques.

Alluxa’s thin film optical filter technology has advanced to the point where the spectral slopes and blocking levels are challenging even the best metrology equipment and techniques. This paper discusses the issues and provides solutions to measuring the spectral response of this new class of high performance filters.

(more…)

Learning Center, White Papers

Durable, Front Surface Hard Optical Coatings For Replacing Laminated Soft Coatings

03MayMay 3, 2012

Alluxa Engineering Staff, May 2012

Alluxa’s proprietary high speed plasma deposition technology for the first time delivers the optical performance and durability of hard coated optical filters at laminated soft coating pricing.

Soft coatings, also known as laminated coatings are well known to possess poor environmental durability, poor temperature stability, low transmission, high optical scatter and low blocking levels, yet they are still widely used due to their low cost, ready availability and legacy status. Alluxa’s proprietary high speed plasma deposition technology for the first time delivers the optical performance and durability of hard coated thin film optical filters at laminated soft coating pricing. (more…)

Learning Center

Thin Film Glossary

19SepSeptember 19, 2010

(more…)

Learning Center

Alluxa Learning Center