Reflective Neutral Density (ND) Filter
| Overview: Reflective Neutral Density (ND) Filters provide uniform attenuation over the broad spectral range from 400 to 1100 nm. Reflective ND filters consist of an N-BK7 glass or UV fused silica substrate with a metal (Inconel) coating deposited on one side. Inconel is a metallic alloy that ensures flat spectral response from the UV to the near IR. To prolong the lifetime of reflective ND filters, we recommend using non-contact cleaning methods (such as compressed air) to prevent damage to the coating and avoiding the use of these filters in humid environments to prevent oxidation. Although these are reflective ND filters, the Inconel coating does absorb some of the incident light, which limits the use of these filters to low-power applications. To achieve the best performance, light should be incident on the side with the Inconel coating, this allows attenuation to occur before etalon effects occur within the filter's substrate. General Specifications Of Reflective Neutral Density (ND) Filter: | Material | BK7, UV Fused Silica | | Dimension Tolerance | +0.0/-0.2mm | | Thickness Tolerance | ±0.2mm | | Surface Quality | 80/50 scratch and dig | | Clear Aperture | >90% | | Flatness | <2λ@632.8nm | | Parallelism | <5 arc minutes | | Chamfer | Protective<0.5mmx45° | | Coating | Metallic (Inconel) reflective coating | | OD Tolerance | OD±10%@Design Wavelength | Standard Products Of Reflective Neutral Density (ND) Filter: | PN. | Dimension (mm) | Thcikness (mm) | OD | Transmission (%) | Design Wavelength (nm) | | RNDF25-0.1-400-1100 | 25.4 | 2 | 0.1 | 79 | 400-1100nm | | RNDF25-0.2-400-1100 | 25.4 | 2 | 0.2 | 63 | 400-1100nm | | RNDF25-0.3-400-1100 | 25.4 | 2 | 0.3 | 50 | 400-1100nm | | RNDF25-0.4-400-1100 | 25.4 | 2 | 0.4 | 40 | 400-1100nm | | RNDF25-0.5-400-1100 | 25.4 | 2 | 0.5 | 32 | 400-1100nm | | RNDF25-0.8-400-1100 | 25.4 | 2 | 0.8 | 16 | 400-1100nm | | RNDF25-1.0-400-1100 | 25.4 | 2 | 1.0 | 10 | 400-1100nm | | RNDF25-2.0-400-1100 | 25.4 | 2 | 2.0 | 1 | 400-1100nm | | RNDF25-3.0-400-1100 | 25.4 | 2 | 3.0 | 0.1 | 400-1100nm | | RNDF25-4.0-400-1100 | 25.4 | 2 | 4.0 | 0.01 | 400-1100nm | Spectrum Graphs of Reflective Neutral Density (ND) Filter: | 400-1100nm Reflective ND filter OD0.1  | 400-1100nm Reflective ND filter OD0.2  | | 400-1100nm Reflective ND filter OD0.3  | 400-1100nm Reflective ND filter OD0.4  | | 400-1100nm Reflective ND filter OD0.5  | 400-1100nm Reflective ND filter OD0.8  | | 400-1100nm Reflective ND filter OD1  | 400-1100nm Reflective ND filter OD2  | | 400-1100nm Reflective ND filter OD3  | 400-1100nm Reflective ND filter OD4  | |