The circular gradient neutral density filter is a sophisticated and powerful optical element that can achieve linear attenuation of light intensity in a circular area. This filter is made using a special process. By coating one or more layers of gradient density films on an optical glass substrate, the light can be attenuated according to a predetermined rule when passing through the filter. The circular gradient neutral density filter not only maintains the neutral distribution of the spectrum, that is, it has the same attenuation effect on light of different wavelengths, but also has a wide range of applications and flexible usage methods.
Model:Neutral Density Filters
Specifications: Customized
Material: Optical Glass
Technical Parameters
Circular gradient neutral density filters (circular gradient density filters for short) can linearly attenuate light intensity by rotating the filter, achieve precise adjustment of light energy in the circular linear direction, and make light energy adjustable and controllable while maintaining neutral spectral light energy distribution. This type of filter can be used in fields such as natural light and laser. Combining two filters and rotating them in reverse can achieve a fixed density attenuation effect in a larger limited area. Product sizes are available from 25mm to 100mm. Spectral range 250nm-2500nm. Density filters of special size, density, and wavelength can be customized.
Product Specifications
| Substrate | BK7 、Fused Silica |
| Thickness tolerance | ±0.1mm |
| Clear Aperture | 90% of the total area |
| Parallelism | 3’ |
| Surface quality | 80-50 |
| Optical density standard deviation | ±5% |
| Calibration wavelength | 550nm |
| Design wavelength | 380nm-2000nm(BK7)250nm-2500nm(Fused Silica) |
Standard products
| size(mm) | OD | T% | Substrate |
| Φ12.7 | 1.0 | 10.0 % | BK7 |
| Φ12.7 | 2.0 | 1.0% | BK7 |
| Φ12.7 | 3.0 | 0.1% | BK7 |
| Φ12.7 | 4.0 | 0.01% | BK7 |
| Φ60 | 1.0 | 10.0 % | BK7 |
| Φ60 | 2.0 | 1.0% | BK7 |
| Φ60 | 3.0 | 0.1% | BK7 |
| Φ60 | 4.0 | 0.01% | BK7 |
| 50 * 50 | 1.0 | 10.0 % | BK7 |
| 50 * 50 | 2.0 | 1.0% | BK7 |
Standard density sheet set
| size | series | Substrate |
| Φ12.7 | A | BK7 |
| Φ12.7 | B | BK7 |
| Φ25.4 | A | BK7 |
| Φ25.4 | B | BK7 |
| Φ60 | A | BK7 |
| Φ60 | B | BK7 |
| 50 * 50 | A | BK7 |
| 50 * 50 | B | BK7 |
Series Type
| OD | |||||||||
| A | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 |
| T% | |||||||||
| B | 15% | 20% | 25% | 30% | 40% | 50% | 60% | 70% | 80% |
Other dimensions, optical density, wavelength and other parameters can be customized according to customer needs. You are welcome to contact us.
Application areas
Laser: used for adjusting and controlling light energy in laser systems.
Optical communication: used for attenuation and regulation of light signals in optical communication equipment.
Photography: used to adjust light intensity in photography to achieve better shooting effects.
Astronomy: used to reduce starlight intensity and protect observation equipment in astronomical observation.
Laboratory research: used for various light energy adjustment and control experiments in optical laboratories.
