Round Continuously Variable Neutral Density Filters
Circular Variable Neutral Density (ND) Filters are continuously variable over 270° of the filter. These filters provide linear attenuation of incident light by rotating the filter. The filters are designed to be spectrally flat from 380 to 2000nm in H-K9L and 250-2500nm in Uv fusedsilica, they can provide excellent attenuation for spectrometers and other optical instruments.These filters have optical densities ranging from 0.04 to 4.0. The optical density increases linearly from the start ofthe coating.
Parameters
| Substrate Material：See details in the list | Surface Quality：60/40 |
| Outer Diameter tolerance：+ 0/ -0.25 mm | Surface flatness：λ/cm²@633 nm |
| Inner Diameter tolerance：+ 0.25/ -0.00 mm | Optical Density Linearity：+ / -5% |
| Thickness：2 mm | Optical Density Tolerance：+ / -5% |
| Thickness tolerance：± 0.25 mm | Spectral Range：See details in the list |
| Parallelism：≤ 3′ |
Model
| Material | Spectral Range(nm) | Outer Dia.(mm) | Inner Dia.(mm) | Coating Radial Angle | CA(mm) | Optical Density | Coating |
| H-K9L | 380-2000 | 25.0 | 7.5 | 270°±5° | φ9.5~φ22 | 0.04-4 | Uncoated |
| 50.0 | 7.5 | φ9.5~φ47 | 0.04-4 | ||||
| 100.0 | 8.3 | φ9.5~φ97 | 0.04-4 | ||||
| 25.0 | 7.5 | φ9.5~φ22 | 0.04-4 | Ravg < 0.5% @420~670nm AOI:0° | |||
| 50.0 | 7.5 | φ9.5~φ47 | 0.04-4 | ||||
| 100.0 | 8.3 | φ9.5~φ97 | 0.04-4 | ||||
| 25.0 | 7.5 | φ9.5~φ22 | 0.04-4 | Ravg < 0.5% @670~1000nm AOI:0° | |||
| 50.0 | 7.5 | φ9.5~φ47 | 0.04-4 | ||||
| 100.0 | 8.3 | φ9.5~φ97 | 0.04-4 | ||||
| JGS1 | 250-2500 | 25.0 | 7.5 | 270°±5° | φ9.5~φ22 | 0.04-4 | Uncoated |
| 50.0 | 7.5 | φ9.5~φ47 | 0.04-4 | ||||
| 100.0 | 8.3 | φ9.5~φ97 | 0.04-4 |