Metallic Neutral Density Filters

Metallic-coated neutral density (ND) filters obtain their optical density from a metal alloy coating on a substrate determined by the wavelength region of interest. Unlike the all-dielectric or absorption type, the metallic type ND filter employs a combination of absorption and reflection to reduce the intensity of light. While able to withstand more incident energy than the absorptive type, metallic ND filters are suitable only for low-power applications. (Note: If used in series, these filters should be tilted to avoid multiple reflections and any reduction of density).

Features
Provides attenuation with greater linearity over a wide spectral range
Reduces thermal effects in low-power laser applications
Delivers superior durability
Soda lime glass, fused silica and custom substrates available
General Specifications
Thickness1.5±0.5 mm
Dimensional Tolerances+0/-0.2 mm
Clear Aperature90% of outside dimension
Surface Quality60/40 per MIL-0-13830B
Coating AdherencePer MIL-M-13508C
HumidityPer MIL-STD-810F
Max. Operating Temperature+100 °C
Substrate MaterialsGlass (350-2000 nm region) or fused silica (250-2000 nm region)
Optical QualityGlass: Flatness of 3-5 waves per inch and parallelism of 3 arc minutes or better
Fused Silica: Flatness of λ/4 per inch and parallelism of 30 arc seconds or better
MechanicalUnmounted
OptionalMountec in threaded ring - for Threaded Ring Sizes ask our expert on the right

 

 Metallic Neutral Density Specifications

Transmission Deviation From Nominal (%)
Optical DensityNominal Transmission (%)250-350 nm350-800 nm800-2000 nm
0.10
0.15
0.20
79.5
70.8
63.0
±9.0
±8.0
±6.0
±3.0
±3.0
±2.0
±9.0
±8.0
±6.0
0.30
0.40
0.50
50.0
39.1
31.6
±5.0
±4.0
±4.0
±2.0
±1.5
±1.5
±5.0
±4.0
±4.0
0.60
0.70
0.80
25.0
20.0
15.5
± 4.0
± 4.0
± 4.0
± 1,5
± 1.5
± 1.5
± 4.0
± 4.0
± 4.0
0.90
1.00
1.30
12.6
10.0
 5.0
± 3.5
± 3.5
± 3.0
± 1.0
± 1.0
± 1.0
± 3.5
± 3.5
± 3.0
1.50
2.00
2.50
3.2
1.0
0.32
± 1.5
± 0.5
± 0.15
± 0.5
± 0.2
± 0.07
± 1.5
± 0.5
± 0.15
3.00
4.00
0.10
0.01
± 0.06
± 0.01
± 0.05
+0.01/-0.008
±0.1(nominal)
±0.01(nominal)

 

Visible/Near Infrared Region (Glass Substrate, 350-2000 nm, available in Ø12.5, 25 and 50 mm and 50 mm SQ)

Optical DensityNominal Transmission (%)Part Number
0.10
0.15
0.20
79.43
70.79
63.10
010FN52
015FN52
020FN52
0.30
0.40
0.50
50.12
39.81
31.62
030FN52
040FN52
050FN52
0.60
0.70
0.80
25.12
19.95
15.85
060FN52
070FN52
080FN52
0.90
1.00
1.30
12.59
10.00
5.01
090FN52
100FN52
130FN52
1.50
2.00
2.50
3.16
1.00
0.32
150FN52
200FN52
250FN52
3.00
4.00
0.10
0.01
300FN52
400FN52

 

Ultraviolet/Visible/Near Infrared Region (Fused Silica, 250-2000 nm, available in Ø12.5, 25 and 50 mm and 50 mm SQ)

Optical DensityNominal Transmission (%)Part Number
0.10
0.15
0.20
79.43
70.79
63.10
010FN46
015FN46
020FN46
0.30
0.40
0.50
50.12
39.81
31.62
030FN46
040FN46
050FN46
0.60
0.70
0.80
25.12
19.95
15.85
060FN46
070FN46
070FN46
0.90
1.00
1.30
12.59
10.00
5.01
090FN46
100FN46
130FN46
1.50
2.00
2.50
3.16
1.00
0.32
150FN46
200FN46
250FN46
3.00
4.00
0.10
0.01
300FN46
400FN46
Calibration
Attenuation
Low-Power Lasers
Scientific Measurements and Research
Machine Vision and other imaging applications

Contacts

Request further information
Product Manager - Optics
+49 6151 8806-56
Fax: +49 6151 8806956
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