- Neutral density (ND) filters are used to attenuate incident radiation without altering its spectral distribution. The neutral density value of an ND filter is related to the transmittance by: D=Log(1..
Filters
Neutral Density Filters
Description
Neutral density (ND) filters are used to attenuate incident radiation without altering its spectral distribution. The neutral density value of an ND filter is related to the transmittance by:
D=Log(1/T)
Optical Density: D
Transmittance: T
Neutral Density Color Glass Filter
Specifications:
| Material: | Optical Neutral Density Glass |
| Flatness: | 2l per 25 mm |
| Surface Quality: | 80/50 |
| Parallelism: | 3' |
| Dimension: | circle (dia.25.4mm typical) or square |
| Dimension Tolerance: | +/-0.2mm |
| Optical Density Tolerance: | ±5% |
Metallic Coated Neutral Density Filter
Metallic coated ND filters are glass or quartz substrates with a precision metallic coating (Inconel) that provides uniform attenuation across a wide spectral range.
Specifications:
| Material: | BK7 glass and Fused Silica |
| Flatness: | 2l per 25 mm |
| Surface Quality: | 80/50 |
| Parallelism: | 3' |
| Dimension Tolerance: | +/-0.2mm |
| Coating: | Vacuum-deposited metallic alloy |
| Optical density Tolerance: | +/-5% |