BP640nm Bandpass Filter | FWHM 8nm, Thickness 1.0mm
The BP640-8nm-1.0mm bandpass filter represents advanced optical engineering for applications demanding exceptional wavelength precision in the deep red spectral region. This ultra-narrow bandpass filter features an extraordinarily tight 8nm full width at half maximum (FWHM) centered at 640nm with transmission greater than 90% across the 638-640nm passband. This exceptional spectral selectivity makes it ideal for Cy5, Alexa Fluor 647 detection, laser line filtering, and multi-channel fluorescence applications requiring superior wavelength discrimination. With comprehensive blocking from 350-1100nm at transmission less than 1%, this filter ensures clean signal isolation in spectrally demanding environments. The compact 1.0mm substrate thickness enables integration into space-constrained optical assemblies while maintaining excellent optical performance. Manufactured by OPTOStokes using advanced high precision coating technology, this filter delivers the precision required for high-end research and analytical instrumentation.
Technical Specifications
| Parameter | Specification |
|---|---|
| Center Wavelength (CWL) | 640nm ± 2nm at T greater than 90% |
| Transmission Range | 638-640nm at T greater than 90% |
| Full Width at Half Maximum (FWHM) | 8nm ± 2nm |
| Blocking Range | 350-1100nm at T less than 1% |
| Optical Density (OD) | Greater than 2.0 (equivalent to T less than 1%) |
| Substrate Thickness | 1.0mm |
| Surface Quality | 60/40 scratch-dig per MIL-PRF-13830B |
| Coating Type | Hard ion-assisted deposition, precision multi-cavity design |
Key Performance Features
This narrow wavelength filter achieves exceptional spectral performance through its ultra-narrow 8nm bandwidth design. The extraordinarily tight FWHM provides superior wavelength discrimination, enabling precise isolation of deep red fluorophore emissions and separation of closely spaced spectral features that would overlap with conventional 15-25nm bandpass filters. This level of spectral precision is essential for multi-color fluorescence microscopy, flow cytometry panels with dense channel packing, and high-resolution spectroscopy applications.
The precisely controlled transmission window spanning just 638-640nm represents an exceptionally narrow passband, offering wavelength selectivity that exceeds standard optical filters by significant margins. Peak transmission greater than 90% within this restrictive window ensures efficient signal collection despite the narrow bandwidth. This combination is achieved through sophisticated thin film coatings design and precision deposition control, resulting in excellent signal-to-noise ratios for photon-limited applications.
Comprehensive blocking performance with transmission below 1% (optical density greater than 2) extends across the full 350-1100nm spectral range, effectively suppressing orange channel crosstalk from 590-620nm, completely rejecting far-red channels at 670-700nm, and eliminating near-infrared interference. This broad rejection ensures clean fluorescence detection even in spectrally crowded multi-parameter systems.
The compact 1.0mm substrate thickness delivers critical advantages for modern optical instrument design. The minimal thickness reduces optical path length, virtually eliminates focal shift, and enables high-density filter packing in automated filter wheels. The reduced mass facilitates faster switching speeds in motorized mechanisms and minimizes bearing loads in precision positioning systems.
Applications
The BP640-8nm-1.0mm filter excels in demanding applications requiring extreme spectral precision in the deep red region:
Multi-Channel Fluorescence Microscopy: Advanced imaging systems utilizing 5-8 fluorescence channels require ultra-narrow filters to prevent spectral overlap. The BP640 filter enables precise detection of Cy5 (emission maximum at 670nm with significant emission at 640nm), Alexa Fluor 647, and other deep red fluorophores while maintaining complete separation from orange mCherry/Texas Red channels at 605-620nm and far-red Alexa Fluor 680 channels at 700-720nm. Super-resolution microscopy and multi-parameter cell biology studies benefit from this exceptional spectral purity.
Flow Cytometry: High-parameter flow cytometry panels with 20-30 markers create extreme spectral crowding. The 640nm region is particularly dense with APC, Alexa Fluor 647, and various tandem conjugates. The 8nm bandwidth provides the precision necessary to isolate specific fluorophore emissions and minimize compensation requirements. Clinical diagnostics and immunophenotyping applications rely on this performance for accurate cell population discrimination.
Laser Line Filtering: Red diode lasers at 638nm and 640nm require precise wavelength selection and amplified spontaneous emission suppression. The BP640 filter isolates desired laser wavelengths while rejecting adjacent spectral content. Laser bandpass filter applications include Raman spectroscopy, laser-based analytical instruments, and optical metrology systems.
Confocal and Spinning Disk Microscopy: Laser scanning systems using 633nm HeNe or 638nm diode laser excitation benefit from the narrow bandwidth for efficient Cy5 emission collection while completely blocking scattered laser light. The 1.0mm thickness minimizes focal shift in precision optical systems while providing adequate mechanical stability.
Single-Molecule Detection: Ultra-sensitive detection techniques including TIRF microscopy and single-particle tracking require filters with extreme spectral purity to isolate weak fluorescence signals. The 8nm bandwidth minimizes background from adjacent channels and autofluorescence, enabling detection of individual fluorophore molecules.
Customization and Service
OPTOStokes provides comprehensive customization for ultra-narrow filter applications. Center wavelength can be precisely tuned across the 635-645nm range with sub-nanometer accuracy to match specific laser lines or fluorophore emission peaks. FWHM can be optimized from 6nm for ultimate resolution to 10nm for increased light collection. Enhanced blocking specifications achieving OD greater than 3 or OD greater than 4 can be implemented in critical spectral regions.
Geometric options include circular formats from 12.5mm to 50mm diameter, plus square, rectangular, and custom bandpass shapes. The 1.0mm thickness can be maintained for maximum compactness or adjusted to 0.7mm for ultra-compact systems or 1.5mm/2.0mm for enhanced rigidity. Mounting solutions range from unmounted filters to pre-mounted configurations in threaded rings and filter cubes.
Quality and Availability
Every BP640-8nm-1.0mm filter undergoes rigorous spectral verification using research-grade spectrophotometers with sub-nanometer resolution. Full transmission curves document center wavelength accuracy, FWHM consistency, peak transmission, and blocking performance. Surface quality inspection and dimensional measurements ensure compliance with specifications. OPTOStokes maintains ISO 9001:2015 certification for consistent quality across all production.
Stock availability of common configurations enables rapid delivery. Custom specifications typically ship within 3-4 weeks. Volume production capabilities support OEM requirements with guaranteed batch-to-batch consistency.
Contact Us
The BP640-8nm-1.0mm filter exemplifies OPTOStokes' expertise in ultra-narrow bandpass filter technology. Contact sales@optofilters.com to discuss requirements, request detailed specifications, or obtain pricing. Visit www.optofilters.com for complete technical resources and product information.
