Rectangular Continuously Variable Neutral Density Filters
Rectangular Continuously Variable Neutral Density Filters are ideal for precise adjustments of spectrophotometers, monochromators and lasers. Optical density varies linearly across the length of these continuously variable neutral density filters. 380 to 2000nm in H-K9L and 250-2500nm in UV fused silica, they can provide excellent attenuation for The filters are designed to be spectrometers and other optical instruments. The filters are available in 25.4 x 76.2mm and 10 x 50mm dimensions, with varying optical densities.
These filters have optical densities ranging from 0.04 to 4.0. The optical density increases linearly from the start of the coating.
Parameters
| Substrate Material：H-K9L/JGS1 | Surface flatness：< λ/25 mm@633 nm |
| Dimension tolerance：+ 0/- 0.25 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′ | Coating：See details in the list |
| Surface Quality：60/40 |
Model
| Material | Spectral Range(nm) | Coating | L(mm) | W(mm) | Length of Coating area | Optical Density | Length E1 | Length E2 |
| H-K9L | 380-2000 | Uncoated | 50.0 | 10.0 | 44 | 0.04-4 | 5 | 1 |
| 76.2 | 25.4 | 56.2 | 19 | 1 | ||||
| Ravg<0.5% @420~670nm AOI:0° | 50.0 | 10.0 | 44 | 5 | 1 | |||
| 76.2 | 25.4 | 56.2 | 19 | 1 | ||||
| JGS1 | 250-2500 | Uncoated | 50.0 | 10.0 | 44 | 5 | 1 | |
| 76.2 | 25.4 | 56.2 | 19 | 1 |