Optical Filters Customizations
What we can make
Bandpass Filters
An optical bandpass filter allows light within a designated wavelength range to pass through while effectively blocking light at wavelengths outside this range.
Key Characteristics
- Center Wavelength (CWL): The midpoint of the filter's passband.
- Full Width at Half Maximum (FWHM): The width of the passband at half the maximum transmission level, indicating the range of wavelengths transmitted.
- Peak Transmission: The maximum percentage of light that can pass through the filter.
Shortpass Filter
A shortpass filter is an optical device that allows short wavelengths of light to pass through while blocking longer wavelengths.
Key Characteristics
- Cutoff Wavelength: The specific wavelength at which the filter starts to block light. This is typically defined at 50% of the peak transmission level.
- Transmission Range: Shortpass filters are designed to transmit wavelengths below the cutoff while blocking those above it.
- Slope of Transition: The steepness of the transition from the passband to the blocked range can vary, with some filters offering a sharper cutoff than others
Longpass Filter
A longpass filter is an optical device that allows longer wavelengths of light to pass through while attenuating shorter wavelengths.
Key Characteristics
- Cut-on Wavelength: The specific wavelength at which the filter starts to transmit light effectively, typically defined at 50% of peak transmission.
- Transmission Range: Longpass filters are designed to transmit wavelengths above the cut-on wavelength while blocking those below it.
- Edge Steepness: The transition from blocking to transmitting can vary; some longpass filters have a sharp cutoff, referred to as edge filters.
Notch Filter
Notch filters are used to block specific laser wavelengths while allowing other light to pass through, which is crucial in applications like fluorescence microscopy and spectroscopy
Dichroic Filters
A dichroic filter is an optical filter that selectively transmits light of a small range of colors while reflecting other colors.
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Design and Specification
Before production begins, the specifications of the optical filter must be clearly defined. This includes the wavelength range, bandwidth, transmission requirements, size, and shape. Advanced software is often used to model the filter's performance and optimize its design.
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Substrate Preparation
The substrate material, which can be glass, plastic, or another transparent material, is prepared. This involves cutting the substrate to the required size and shape and then polishing it to achieve the necessary optical quality. The surface must be free of imperfections to ensure the filter's effectiveness.
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Deposition of Optical Coatings
Coating AssetThis is a critical step for many types of optical filters, especially interference filters. Thin layers of different materials are deposited on the substrate in a vacuum environment using techniques such as sputtering, evaporation, or chemical vapor deposition. The specific materials and thicknesses of the layers determine the filter's optical properties.
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Dicing
A diamond blade is used to cut the substrate into smaller filter. Our equipment is capable of machining optical glass into sizes as small as 1 mm.
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Assembly
If the filter consists of multiple components (e.g., several coated substrates stacked together), these are assembled. This step must be performed with precision to ensure the components are correctly aligned.
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Final Testing and Quality Assurance
Inspection AssetThe finished filter is subjected to rigorous testing to ensure it meets the required specifications. This includes measuring its transmission and reflection properties across the relevant wavelength range, verifying its physical dimensions, and assessing its durability.
