When narrow FWHM is worth the tradeoff
Narrower bandwidth improves wavelength discrimination, but it can reduce throughput. It is most useful for laser cleanup, spectral analysis, and tight emission lines.
Narrow Bandpass Filters for Precision Wavelength Selection
Use this page to compare narrow passbands by center wavelength, FWHM, blocking level, and thickness. These filters are intended for applications where spectral selectivity matters more than broad throughput.
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How to Choose
Select the center wavelength around the source or target signal, then choose the narrowest FWHM that still allows enough usable signal. Confirm OD blocking, peak transmission, AOI sensitivity, temperature range, and physical tolerance.
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Narrow Bandpass Filters
These narrow bandpass filters (CWL 405-808nm) provide precise wavelength selection with FWHM as narrow as 1nm and OD6+ out-of-band blocking. They are suited to Raman spectroscopy, laser clean-up, confocal microscopy, and high-sensitivity fluorescence detection where wavelength purity is critical.
View full Ultra-Narrow Bandpass Filters
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| Model | CWL (nm) | Transmittance | FWHM (nm) | Optical Density | Note |
|---|---|---|---|---|---|
| STO-BP405/20 | 405±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP450/20 | 450±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP460/20 | 460±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP470/20 | 470±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP490/20 | 490±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP520/20 | 520±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP532/20 | 532±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP540/20 | 540±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP550/20 | 550±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP565/20 | 565±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP590/20 | 590±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP635/20 | 635±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP650/20 | 650±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP680/20 | 680±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP710/20 | 720±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP750/20 | 750±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP780/20 | 780±3 | T≥90% | 20:5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP800/20 | 800±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP808/20 | 808±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP820/20 | 820±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP850/20 | 850±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP880/20 | 880±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP940/20 | 940±3 | T≥90% | 20±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP365/30 | 365±3 | T≥90% | 30±5 | OD≥3@200-800 | Other parameters can be customized |
| STO-BP405/40 | 405±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP450/50 | 450±5 | T≥90% | 50±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP462/60 | 462±5 | T≥90% | 60±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP470/40 | 470±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP490/40 | 490±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP520/40 | 520±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP532/40 | 532±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP540/40 | 540±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP550/50 | 550±5 | T≥90% | 50±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP565/40 | 565±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP590/40 | 590±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP635/50 | 635±5 | T≥90% | 50±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP650/50 | 650±5 | T≥90% | 50±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP680/40 | 680±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP780/40 | 780±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP808/40 | 808±4 | T≥90% | 40±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP850/50 | 850±5 | T≥90% | 50±5 | OD≥3@350-1100 | Other parameters can be customized |
| STO-BP940/50 | 940±5 | T≥90% | 50±5 | OD≥3@350-1100 | Other parameters can be customized |
Related Engineering Notes
Blocking outside the passband
For high-sensitivity detectors, OD outside the passband can matter as much as peak transmission. Confirm the blocking range, not just the center wavelength.
Custom CWL requests
If a catalog wavelength is close but not exact, specify target CWL, tolerance, FWHM, blocking range, and working angle in the quote request.
FAQ
When should I choose a narrow bandpass filter?
Choose a narrow bandpass filter when nearby wavelengths must be rejected, such as laser cleanup, fluorescence detection, Raman, and high-sensitivity instruments.
Does a narrower FWHM always perform better?
Not always. Narrower filters improve selectivity but may reduce signal tolerance if the source drifts or the angle of incidence changes.
Can narrow bandpass filters be made at custom wavelengths?
Yes. Custom CWL, FWHM, blocking range, size, and substrate options are available for OEM requirements.
Quality & Compliance
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For OEM programs, laboratory instruments, and industrial systems, OPTOStokes keeps quality, material compliance, and engineering support visible from the start of supplier evaluation.
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Custom coating and dimensions
Wavelength, FWHM, substrate, AOI, size, and mounting requirements can be reviewed with engineering.
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Quote and data review
Share target wavelength, blocking level, transmittance, and drawing requirements for a focused quote.
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