{"id":3663,"date":"2026-11-03T13:16:04","date_gmt":"2026-11-03T05:16:04","guid":{"rendered":"http:\/\/www.nobetciecza.com\/blog\/?p=3663"},"modified":"2026-11-03T13:16:04","modified_gmt":"2026-11-03T05:16:04","slug":"what-is-the-spectral-sensitivity-of-seya-namioka-flat-field-concave-holographic-grating-4deb-4d3365","status":"publish","type":"post","link":"http:\/\/www.nobetciecza.com\/blog\/2026\/11\/03\/what-is-the-spectral-sensitivity-of-seya-namioka-flat-field-concave-holographic-grating-4deb-4d3365\/","title":{"rendered":"What is the spectral sensitivity of Seya – Namioka Flat – Field Concave Holographic Grating?"},"content":{"rendered":"

If you\u2019ve ever worked with extreme ultraviolet (EUV) or soft X-ray spectroscopy, you know how critical every component is to getting accurate, actionable data at those short, high-energy wavelengths. At our company, we specialize in manufacturing Seya-Namioka Flat-Field Concave Holographic Gratings\u2014one of the most reliable tools for applications ranging from semiconductor metrology to planetary atmospheric research\u2014and one question we get asked more than any other is about their spectral sensitivity. Let\u2019s break this down, plain and simple, from our perspective as a supplier that\u2019s shipped these gratings to labs, research institutions, and manufacturing facilities across the globe. Seya-Namioka Flat-Field Concave Holographic Grating<\/a><\/p>\n

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First, let\u2019s ground this in what a Seya-Namioka design actually is. Invented by Seya and Namioka in the 1950s, this configuration pairs a concave holographic grating with a fixed input and output slit arranged in a 1:1 Rowland circle geometry, adjusted to produce a flat focal plane. Unlike ruled gratings, which have uneven groove depths and spacing that can cause stray light and inconsistencies, holographic gratings are made by interfering two laser beams to etch precise, uniform grooves into the grating surface. That precision directly translates to spectral sensitivity\u2014simply put, how well the grating converts incoming light at a specific wavelength into a measurable signal, and how consistent that performance is across its operating range.<\/p>\n

Spectral sensitivity for any grating boils down to three core factors: efficiency (how much incoming light is diffracted into the desired order), stray light rejection (how little unwanted light hits the detector), and spectral resolution (how well it can distinguish between two very similar wavelengths). For Seya-Namioka flat-field concave holographic gratings, these factors are tailored to the unique needs of EUV and soft X-ray work\u2014wavelengths typically between 1 nm and 200 nm, where most traditional optical components start to break down.<\/p>\n

Let\u2019s start with efficiency, because that\u2019s the most tangible piece of spectral sensitivity for end-users. Holographic gratings have a major advantage over ruled gratings here: we can tailor the groove profile and spacing to optimize for a specific wavelength range, instead of a broad general spectrum. For our Seya-Namioka designs, we engineer the groove density (usually between 600 grooves\/mm and 3600 grooves\/mm, depending on the application) and the blaze angle to maximize diffraction efficiency in the 5 nm to 100 nm EUV range, or 100 nm to 200 nm soft X-ray range, whichever the customer needs. For example, a customer working on analyzing silicon wafer layers for semiconductor manufacturing might order a grating optimized for 13.5 nm EUV, with average diffraction efficiency of 65% across that wavelength band\u2014meaning only 35% of the incoming light is lost, a massive improvement over older ruled gratings which might have struggled to hit 40% in that range. It\u2019s worth noting that efficiency drops off at the edges of the grating\u2019s designed range, which is why we work directly with customers to match the grating\u2019s optimized band to their specific experimental setup, not a one-size-fits-all spec sheet.<\/p>\n

Next, stray light rejection\u2014this is where Seya-Namioka holographic gratings shine, and it\u2019s a critical part of spectral sensitivity for low-signal applications. EUV and soft X-ray experiments often deal with extremely faint light, so stray light (diffracted light from unwanted wavelengths) can completely obscure the signal you\u2019re trying to measure. Holographic gratings have much lower stray light levels than ruled gratings because the uniform holographic grooves don\u2019t have the micro-roughness or irregularities that cause off-plane diffraction. For our Seya-Namioka designs, stray light is typically less than 10^-5, compared to 10^-3 or higher for many ruled gratings. That difference is make-or-break for researchers studying exoplanet atmospheres, where they\u2019re looking for faint spectral lines of oxygen or carbon in a sea of background noise. Over the last 12 months, we\u2019ve supplied gratings to three separate university astrophysics labs, and every one of their feedback notes highlighted the low stray light as a key reason their signal-to-noise ratio improved by 20-30% compared to their previous grating setups.<\/p>\n

Third, spectral resolution, which ties directly to how well the grating can separate two adjacent wavelengths, is another core component of spectral sensitivity. Seya-Namioka\u2019s flat-field design means you can use a standard linear detector (like a CCD or photodiode array) across the entire focal plane, instead of needing a moving point detector to scan a curved Rowland circle. The holographic grooves ensure consistent resolution across that entire flat focal plane, no hot spots or sharp drops at the edges. For our gratings, spectral resolution ranges from 500 for low-resolution work to over 10,000 for high-resolution EUV spectroscopy. For context, a semiconductor customer measuring thin film thickness on 300 mm wafers needs resolution of around 2000, which our 2400 grooves\/mm Seya-Namioka grating delivers reliably, every time.<\/p>\n

Now, it\u2019s important to address the common misconception that spectral sensitivity is a fixed number on a spec sheet. It\u2019s not. It depends heavily on how the grating is used, and that\u2019s where our value as a supplier comes in. The angle of incidence, the order of diffraction you\u2019re working in, and even the detector you pair with the grating all shift spectral sensitivity. For example, a grating optimized for 15 nm at a 85-degree angle of incidence (standard for Seya-Namioka setups) will have higher efficiency at that wavelength than it would at a shallower 60-degree angle. That\u2019s why we don\u2019t just sell gratings\u2014we work with customers to design the exact Seya-Namioka configuration that fits their specific setup. Last year, we worked with a team at a national lab that was struggling with a custom EUV microscope; their off-the-shelf Seya-Namioka grating had 50% efficiency at their target wavelength, but by adjusting the groove density and blaze angle to match their specific angle of incidence, we got their efficiency up to 72% without increasing stray light or sacrificing resolution.<\/p>\n

Another key point specific to Seya-Namioka flat-field concave holographic gratings vs. other grating types: the concave substrate itself doesn\u2019t just hold the grooves\u2014it also acts as a focusing element. That means you don\u2019t need a separate mirror to focus the diffracted light, which reduces optical components in the system and cuts down on light loss from additional surfaces. That integration directly boosts overall spectral sensitivity, because less light is lost before it hits the detector. Ruled gratings often require separate focusing optics, which add reflection losses at each surface, while flat gratings need external focusing elements that can introduce aberrations. The Seya-Namioka\u2019s concave holographic design balances all that to deliver more light to the detector, higher resolution, and lower stray light all in one.<\/p>\n

Let\u2019s also talk about what spectral sensitivity means in practical terms for different industries, because that\u2019s what matters most to our customers. For semiconductor metrology, where precise control of layer thicknesses and composition is critical to advancing node sizes, spectral sensitivity translates to more accurate measurements of the 13.5 nm EUV reflected from wafer layers. A grating with high sensitivity here can detect a 0.1 nm variation in layer thickness, which is the difference between a working 3 nm node wafer and a defective one. For planetary atmospheric research, high spectral sensitivity means detecting faint spectral lines of trace gases in exoplanet atmospheres\u2014lines that are 10,000 times weaker than the background stellar light. For X-ray fluorescence (XRF) spectroscopy, used in forensics and material science, spectral sensitivity lets you accurately identify trace elements in samples, even at concentrations of parts per million.<\/p>\n

We get a lot of questions about how holographic gratings hold up over time, which ties to long-term spectral sensitivity. Unlike ruled gratings, which can have micro-degradation of the groove edges over time from environmental factors like humidity or temperature fluctuations, holographic gratings have a smooth, uniform surface that\u2019s far more resistant to wear. We coat all our Seya-Namioka gratings with a thin layer of aluminum, gold, or iridium, depending on the wavelength range, to further protect the surface and maintain consistent efficiency over years of use. A customer that\u2019s had one of our Seya-Namioka gratings installed in a synchrotron beamline for 7 years recently sent us their annual performance test, and the spectral sensitivity was within 3% of the original spec\u2014something we don\u2019t see as consistently with ruled gratings from other suppliers.<\/p>\n

I want to be transparent about the limits of spectral sensitivity for these gratings, too, because no component is perfect. Seya-Namioka flat-field concave holographic gratings are optimized for EUV and soft X-ray wavelengths, so they\u2019re not suitable for visible or infrared light. For wavelengths above 200 nm, transmission gratings or other grating types will deliver better performance. Also, spectral sensitivity will drop slightly at the very edges of the grating\u2019s groove density range\u2014for example, a 3600 grooves\/mm grating designed for 5 nm to 50 nm EUV will have lower efficiency at 50 nm than at 15 nm, which is why matching the grating\u2019s range to your experiment\u2019s target wavelengths is key.<\/p>\n

At the end of the day, spectral sensitivity is the reason our Seya-Namioka flat-field concave holographic gratings are the choice for leading research labs and semiconductor manufacturers around the world. It\u2019s not just a technical spec\u2014it\u2019s what lets researchers make groundbreaking discoveries about exoplanet atmospheres, and what lets chipmakers build smaller, more powerful semiconducters. We don\u2019t just ship gratings; we work with every customer to understand their specific needs, adjust the design to deliver the right spectral sensitivity, and provide ongoing support to make sure their setup performs as intended.<\/p>\n

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If you\u2019re working on an EUV or soft X-ray spectroscopy project, whether it\u2019s lab research, semiconductor testing, or industrial quality control, and you have questions about how our Seya-Namioka Flat-Field Concave Holographic Gratings can meet your spectral sensitivity requirements, we encourage you to reach out for a no-obligation consultation. We can walk through your setup, discuss wavelength ranges, resolution needs, and any other factors that matter to your work.<\/p>\n

Rowland Circle Grating<\/a> References
\nSeya, M., Namioka, T. (1959). \u201cNew Spectrometer with Concave Grating.\u201d Journal of the Optical Society of America, Vol. 49, No. 5, pp. 466-471.
\nPalmer, C., Loewen, E. (2005). Diffraction Gratings: Applications for EUV and Soft X-Rays. SPIE Press.
\nYashchuk, V.V., et al. (2010). \u201cPerformance of Holographic Concave Gratings for Synchrotron Radiation Beamlines.\u201d Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 616, No. 2-3, pp. 255-263.<\/p>\n

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Jilin Juyao Technology Co., Ltd.<\/a>
As one of the leading seya-namioka flat-field concave holographic grating manufacturers and suppliers in China, we offer a wide range of products with superior quality. Please feel free to wholesale customized seya-namioka flat-field concave holographic grating from our factory. Welcome to view our website for more information.
Address: Room 101, No. 2 Huiwen Road, Nanguan District, Changchun City, Jilin Province, China
E-mail: jyoptix@outlook.com
WebSite: https:\/\/www.jyoptix.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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