This section provides an overview for notch filters as well as their applications and principles. Also, please take a look at the list of 13 notch filter manufacturers and their company rankings. Here are the top-ranked notch filter companies as of November, 2024: 1.Alluxa, 2.Tokyo Instruments, Inc, 3.K&L Microwave.
Table of Contents
A notch filter is an optical filter that attenuates (blocks) light in a specific wavelength band to a very low level, while transmitting light in other wavelength bands at a high transmission rate.
Notch Filters are also called bandstops or bandpass filters. Generally, bandpass filters are used to transmit only light in a specific wavelength band, whereas notch filters do the opposite (blocking the transmission of light in a specific band).
Notch Filters are used to remove excitation light from a single wavelength laser beam. A laser is generally a device that oscillates with an excitation light to produce high intensity and high power.
It emits light at a single wavelength, but the excitation light can be mixed in. Notch Filters can be used for the purpose of extracting the light emitted by the laser and blocking the excitation light.
Notch Filters are also used in Raman spectroscopy and fluorescence spectroscopy, which are analytical scientific instruments that use lasers. By cutting off the light from the excitation light source, etc., and detecting only the Raman spectrum or fluorescence spectrum to be measured, measurements with little background can be made.
Notch Filters are made of a dielectric multilayer film, which are composed of multiple layers of dielectrics with different refractive indices, on an optically polished glass substrate.
The dielectric multilayer film does not absorb light, and the difference in refractive index between the layers causes reflection and interference, thus blocking light in a specific band. The transmittance varies depending on the angle of incidence and polarization (S or P polarization). The center wavelength of the blocked light shifts to shorter wavelengths as the angle of incidence increases.
Dielectric multilayer films are composed of materials with high refractive index (refractive index 2~2.5) such as titanium oxide and tantalum, and materials with low refractive index (1~1.5) such as silicon oxide and magnesium fluoride. These films can be deposited by vapor deposition in a vacuum or by electron beam deposition on a dielectric material.
The surface of the filter is very strong and scratch-resistant due to the dielectric multilayer film and anti-reflective AR coating, etc. It is possible to suppress performance degradation caused by time, temperature, and humidity, and to increase transmittance outside of a specific wavelength region.
In addition, the direction of incidence is determined and is generally indicated by an arrow-like mark on the edge of the filter. Whether the incidence is from the end of the arrow or along the arrow differs depending on the manufacturer, so it is necessary to confirm the direction of incidence in advance.
The following terms are necessary to define the performance of Notch Filters in the selection:
1. Optical Density (OD) indicates how well a Notch Filter blocks laser light of a particular wavelength. 6 indicates transmission to the power of 10 minus 6, or 0.0001%, and the higher the OD value, the higher the blocking ratio.
However, the higher the OD value, the more optical it is and the wider the blocking area tends to be. Therefore, you can select a Notch Filter with an appropriate OD value by checking in advance how much you need to cut from the intensity of the laser to be used and knowing the OD value sufficient for blocking.
2. Center wavelength
The center wavelength is the wavelength at the center of the wavelength range where light does not penetrate the Notch Filter and where the OD value is the largest. Since the main purpose of notch filters is to block lasers, most commercially available notch filters are generally designed so that the center wavelength matches the wavelength of the most frequently used lasers. Some manufacturers produce Notch Filters with a specially selected center wavelength by special order, but they are more expensive than the commercially available ones.
3. Blocking region
The blocking region is the wavelength region where light is blocked by the Notch Filter. It is defined by the full width at half maximum of the region where no light is transmitted. Notch Filters generally have a high transmittance in the wavelength region outside the blocking region, and some filters have a transmittance that decreases as the wavelength region moves away from the blocking region. Therefore, when measuring a broad spectrum, it is necessary to check the transmittance spectrum in the measurement wavelength range in advance, because there is a problem that the target light cannot pass through the Notch Filter.
*Including some distributors, etc.
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K&L Microwave, a subsidiary of Dover Corporation, is a designer and manufacturer of RF and microwave filters, located in Salisbury, Maryland. They offer a range of products including band pass filters, band reject filters, low pass filters, high pass filters, as well as multiplexers, and switches. These products are designed to control and manipulate signals based on their frequencies, allowing for precise signal filtering and routing in electronic systems and communication networks. The company holds quality certifications including AS9100D with ISO9001:2015 certification from Intertek Testing Services and ISO9001:2015 certification from SAI Global Assurance.
Alluxa, founded in 2007 and based in Santa Rosa, California, is a manufacturer and supplier specializing in optical filters and thin-film coatings. The company’s product range includes optical filters like bandpass, notch, and dichroic filters, as well as pressure transmitters and more. They also offer custom and OEM optical filter development for non-standard spectral shapes, unusual coating materials, and other unique technical specifications. Their optical filters and thin-film coatings find applications in microscopy, imaging, flow cytometry and LIDAR technology. Alluxa holds ISO9001:2015 certification and offers technical support in every step of the manufacturing process, serving clients nationwide.
Chroma Technology Corporation, established in 1991 and based in Bellows Falls, Vermont, is a manufacturer and supplier of optical filters and related products. The company’s main activity involves producing precision optical filters used in various applications such as fluorescence microscopy, flow cytometry, and imaging systems. The company's quality products play a crucial role in enhancing light manipulation and detection in scientific research, medical diagnostics, and industrial applications. With a strong effort on modernization and customer satisfaction, Chroma Technology has earned a status as an important provider of optical solutions globally.
KR Electronics, located in Avenel, New Jersey, is a designer and manufacturer of filters for both the commercial and military markets since 1973. They produce various types of filters and custom-synthesized filters for specific applications such as in military, commercial, medical, and communications. Their product line includes bandpass filters, highpass filters, lowpass filters, and root cosine filters, and they employ advanced computer-based techniques for synthesis, analysis, and testing to meet specifications. KR Electronics is ISO 9001:2015 certified and J-STD-001 Certified.
Circutor, established in 1973 and headquartered in Barcelona, Spain, is a manufacturer that develops technology and solutions for the electrical and energy sector. The company's products include measurement and control devices, metering equipment, control systems, and harmonic filtering. It also offers power factor correction and portable power analyzers, such as the MYeBOX-150+3 FLEX-R45. Its products help to reduce CO2 emissions by reducing energy consumption. It serves a range of industries such as generator, tertiary sector, and home use.
Gigahertz Solutions GmbH is a manufacturer of high- and low-frequency field strength measurement technology products established in 1990 and located in Langenzenn, Bayern, Germany. The company offers demand switches for automatically disconnecting electrical devices from power supplies, field strength meters for measuring electromagnetic fields in a range of environments, and shielding materials for providing protection from low- to high-frequency radiation. It also offers measurement accessories for related applications, such as antennae and probes. The company’s products are mainly used by clients in the telecom, electrical engineering, and building biology sectors.
ABBEY ELECTRONIC CONTROLS LTD, founded in 1990 and located in Wigan, United Kingdom, is a manufacturer providing electronic control solutions. The company manufactures a wide range of electronic and gas products, including snow and rain sensors, ignition controllers, and air pressure switches. It also offers related accessories, such as conversion kits, edge connectors, and controller knobs. The company serves original equipment manufacturers (OEMs) across diverse industries, providing electronic solutions to meet their specific needs.
Detas S.p.A. (Detas Group), established in 1978 and headquartered in Rezzato, Brescia, Italy, is an electric and electronic device and component manufacturer and supplier. The company primarily produces wiring devices as well as a line of electronic devices for industrial automation. Its products include power supplies, EMC (electromagnetic compatibility) devices, and entry systems for cables with and without connectors. The company serves the IA, traffic safety, and LED lighting sectors, and its brands include Detas EV Chargers, Haake, and REO Italia.
DETI SAS, founded in 1995 and headquartered in Gouesnou, France, is a manufacturer and supplier of RF and microwave solutions. The company specializes in designing and manufacturing passive microwave products for military applications. It supplies dedicated filters and couplers or combiners for electronic warfare and satcom as well as EMC lab test markets. The company also provides bespoke solutions for the maintenance, repair, or upgrade of embedded defense equipment. It offers services including custom engineering for required specifications, obsolescence treatment, and reverse engineering services for broken or worn-out electronic products.
Tokyo Instruments, Inc., established in 1981, and headquartered in Tokyo, Japan, is a manufacturer of opto-electronics products and systems. The company offers a wide range of products, including laser processing machines, aligning systems, photodetectors, analyzers for photoelectron spectroscopy, and spectroscopy array detectors. Also offered are high-speed, high-sensitivity cameras in UV to IR, and photon detectors or counters. The company's product families consist of the Nanofinder series of 3D Laser Raman Microspectroscopy systems and the iDus Workhorse laboratory and OEM CCD platform for low-light spectroscopy.
Ranking as of November 2024
Derivation MethodRank | Company | Click Share |
---|---|---|
1 | Alluxa |
17.6%
|
2 | Tokyo Instruments, Inc |
14.7%
|
3 | K&L Microwave |
11.8%
|
4 | CIRCUTOR |
8.8%
|
5 | KR Electronics |
8.8%
|
6 | DETI SAS |
5.9%
|
7 | Detas SpA |
5.9%
|
8 | EPA GmbH |
5.9%
|
9 | KVG GMBH |
5.9%
|
10 | Gigahertz Solutions GmbH |
5.9%
|
Derivation Method
The ranking is calculated based on the click share within the notch filter page as of November 2024. Click share is defined as the total number of clicks for all companies during the period divided by the number of clicks for each company.Number of Employees
Newly Established Company
Company with a History
*Including some distributors, etc.
*Including some distributors, etc.
Country | Number of Companies | Share (%) |
---|---|---|
United States of America | 4 | 50.0% |
Germany | 2 | 25.0% |
Spain | 1 | 12.5% |
Japan | 1 | 12.5% |