• 2" x 2"
• Ideal for Low-Power Application(<1 Watt)
• Surface Flatness: λ/10 (at 633 nm)
• Absorptive Glass Reduces Multiple Reflections

Unlike its metallic counterpart, this absorptive ND filter is fabricated from one member of a family of Schott glasses. Each Schott glass has a spectrally flat absorption coefficient in the visible region of 400-650 nm. By varying the type and thickness of the glass used, we are able to produce the entire line of absorptive ND filters from just four types of Schott glass. This absorptive ND filter is ideal for low-power applications and has a damage threshold of 100 W/cm² (CW, Ø1 mm beam @532 nm).

• Diameter Tolerance: +0.0/-0.25
• Clear Aperture: 90% of Total Area
• Surface Flatness (@633 nm): 2λ
• Surface Quality: 40-20 Scratch-Dig
• Parallelism: 10 arsec
• Optical Density: 1.0
• Theoretical Transmission (@ 633 nm): 10%
• Substrate Thickness: 1.89 mm
• Substrate: NG4