Introduction to Bandpass Filters
Optical filters are vital for controlling light in advanced optical systems. OptoStokes’s bandpass filters, designed with precision dielectric coatings, selectively transmit specific wavelength ranges, making them ideal for applications requiring high accuracy, such as spectroscopy and laser systems.
How Bandpass Filters Work
Bandpass filters utilize a Fabry-Perot (F-P) interference cavity formed by multilayer dielectric coatings. By precisely controlling coating thickness and spacing, these filters achieve the desired center wavelength, ensuring accurate spectral selection for diverse applications.
Center Wavelength (CWL)
The center wavelength (CWL) is the midpoint of the filter’s passband, where peak transmittance is achieved. As wavelengths deviate from the CWL, transmittance decreases.
OptoStokes offers a range of CWL options, designed for collimated, normal-incidence light. Non-collimated or angled incidence may cause a blue shift, moving the CWL to shorter wavelengths.
Full Width at Half Maximum (FWHM)
The FWHM defines the spectral bandwidth where transmittance reaches 50% of the peak value. OptoStokes provides bandpass filters with FWHM options of:
- Narrowband: <10 nm, ideal for laser purification and chemical detection.
- Midband: 25–50 nm, suited for machine vision applications.
- Wideband: >50 nm, perfect for fluorescence microscopy.
Laser line filters offer an ultra-narrow FWHM of 3±0.6 nm for high-precision tasks.
Applications of Bandpass Filters
Our bandpass filters excel in:
- Laser Applications: Purifying laser beams and isolating weak signals in LiDAR or ranging systems.
- Spectroscopy: Enhancing signal-to-noise ratio in chemical and fluorescence detection.
- Machine Vision: Improving contrast for defect detection or barcode scanning.
- Fluorescence Microscopy: Isolating specific emission wavelengths for clear imaging.
Why Choose OptoStokes Filters?
As a trusted supplier, OptoStokes delivers:
- High Precision: Bandpass filters for laser applications with accurate CWL and narrow FWHM.
- Custom and Stock Options: Available in 10±2 nm, 25±3 nm, and 50±5 nm, tailored to your needs.
- Global Standards: Quality matching international benchmarks at competitive prices.
