• SM05-Threaded Mount Engraved with Part Number and Optical Density
• Attenuation in the Visible and NIR Spectral Regions

This Ø1" Thorlabs’ Mounted N-BK7 Reflective (Metallic) Neutral Density (ND) Filter provides uniform attenuation over the broad spectral range from 350 to 1100 nm. This filter is mounted in an SM1-Threaded (1.035" -40) cell, making it compatible with components such as Ø1" lens tubes. Our reflective ND filters have optical densities ranging from 0.1 to 4.0.

This filter consists of a N-BK7 glass substrate with a metal (Inconel) coating. Inconel is a very hard metallic alloy that ensures flat spectral response from the UV to the mid IR and is resistant to aging under normal conditions; however, it will oxidize at elevated temperatures. To prevent oxidation, Thorlabs recommends using this ND filter at temperatures below 100° C.

Please note that Thorlabs Neutral Density Filters are not designed as laser safety equipment. For lab safety, Thorlabs offers an extensive line of safety and blackout products, including beam blocks, that significantly reduce exposure to stray or reflected light.

• Substrate: N-BK7 Glass
• Diameter: 25.0 +0.0/-0.5 mm (unmounted)
• Mount: Engraved SM1L03
• Thickness: 1.0 ± 0.25 mm (unmounted)
• Clear Aperture: 90% Outer Diameter
• Surface Accuracy: <5λ
• Surface Quality: 40-20 Scratch-Dig
• Parallelism: <3 arcmin
• Optical Density (@ 633 nm): 3.0 (0.1%)