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Gradient Filters

Gradient Filters

Custom Spatially Varying Optical Transmission Solutions

Gradient filters, also referred to as graduated optical filters, are designed with transmission characteristics that vary continuously across the clear aperture.Unlike conventional optical filters with uniform spectral performance over the entire surface, gradient filters provide spatially dependent control of light intensity and/or wavelength response, enabling precise optical compensation and advanced system-level optimization.By combining precision thin-film coating technologies with controlled gradient designs, LUMINA delivers custom gradient filter solutions for demanding industrial, scientific, and imaging applications.

Available Gradient Filter Designs
·Gradient Neutral Density (ND) Filters
—Spatially varying attenuation with spectrally neutral behavior
·Linear Variable Bandpass Filters
—Center wavelength varies as a function of position
·Linear Variable Longpass or Shortpass Filters
—Cut-on wavelength varies linearly along the filter length
·Gradient Dichroic Filters
—Spatially varying reflection and transmission characteristics (upon request)

All gradient filter designs are application-specific and can be fully customized.

Specification

Typical Custom Parameters

Representative design ranges shown below. Actual specifications are defined based on application requirements.


Parameter

Typical Capability

Gradient Filter Type

Linear Variable Filter (LVF)

Spectral Function

Longpass/Shortpass/ Bandpass / ND

Gradient Direction

Linear (standard), radial or custom upon request

Wavelength Range

250 – 2500 nm (design dependent)

Common Range

400 – 1000 nm (VIS–NIR)

Linear Variable Rate

1–20 nm/mm (up to 50 nm/mm available)

Peak Transmission

≥85% (Longpass / Shortpass), ≥60–80% (Bandpass)

Blocking Level

OD2–OD4 (higher upon request)

Substrate Size

Up to 100 × 20 mm (typical)

Thickness

0.5 – 2.0 mm


Bandpass Gradient Filters (Applicable to Bandpass Designs Only)

For gradient bandpass filters, additional spectral parameters apply:

Center wavelength varies linearly with position

Typical bandwidth (FWHM): 1% – 5% of CWL

Out-of-band blocking: OD2 – OD4

These filters are commonly used in spectral scanning, multi-wavelength imaging, and compact spectroscopic systems.


Gradient Profiles

Gradient behavior can be customized according to optical system geometry:

Linear gradient (standard LVF design)

Radial or circular gradient

Zonal or segmented gradient

Custom-defined gradient geometries


Key Features

Smooth and continuous variation: No abrupt transitions or interference fringes

Multiple gradient types: Linear, circular, and zonal gradients

Broad spectral coverage: UV to IR

Custom coating combinations: AR or protective layers available

High precision control: Transmission variation error <±1%

Applications

Spectral scanning and wavelength selection

Optical testing and calibration systems

Machine vision and illumination correction

Laser intensity and wavelength control

Scientific instrumentation and analytical equipment

Get in Touch With Our Sales Team

LUMINA is committed to becoming your reliable partner in the high-end optical field. If you have special optical needs or application challenges that cannot be met by standard products, please contact us to start your journey of customized optical solutions!
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