Absorptive Neutral Density Filters attain functions by absorbing light with minimal reflection. Holmarc’s absorptive neutral density filters are made by four special filter glass materials from Schott. Each schott filter glass material has a spectrally flat absorption coefficient in the visible region. Since optical density is a function of the type of glass material and thickness, by varying these we are able to produce the entire line of absorptive ND filters. Holmarc offers Absorptive ND filters in unmounted and mounted options. Optical density of the absorptive ND filter is related to the transmission by the following equation;
OD = log10 ( 1 / T ), or T = 10-OD
Materials | : | NG1, NG4, NG9 & NG11 |
Surface quality | : | 40 - 20 ( scratch-dig ) |
Dimensional Tolerance | : | +0.00, -0.2 nm |
Clear aperture | : | 90 % |
Surface flatness | : | λ / 4 @ 632.8 nm |
Parallelism | : | ≤ 10 arc sec |
Damage threshold | : | < 500 mJ / cm2 @ 532 nm CW laser |
Absorptive Neutral density filters of custom sizes are available. Variety of cells and holders are available from Holmarc. For custom designs, contact at mail@holmarc.com
Reflective Neutral Density Filters attenuate the light beam by a combination of reflection and absorption. Holmarc’s reflective neutral density filters...
Our Circular Variable ND filters (Mounted) are designed to provide continuous variable attenuation by rotating the filter...
Model No. | Diameter D ( mm ) |
Optical Density (OD) |
Material | Price ($) | ||
Unmounted | Mounted | Unmounted | Mounted | |||
HO-NDA-12.5-0.1 | HO-NDA-12.5M-0.1 | 12.5 | 0.1 | NG11 | 20.00 | 37.00 |
HO-NDA-12.5-0.2 | HO-NDA-12.5M-0.2 | 12.5 | 0.2 | NG11 | 20.00 | 37.00 |
HO-NDA-12.5-0.3 | HO-NDA-12.5M-0.3 | 12.5 | 0.3 | NG11 | 20.00 | 37.00 |
HO-NDA-12.5-0.4 | HO-NDA-12.5M-0.4 | 12.5 | 0.4 | NG4 | 20.00 | 37.00 |
HO-NDA-12.5-0.5 | HO-NDA-12.5M-0.5 | 12.5 | 0.5 | NG4 | 20.00 | 37.00 |
HO-NDA-12.5-0.6 | HO-NDA-12.5M-0.6 | 12.5 | 0.6 | NG4 | 20.00 | 37.00 |
HO-NDA-12.5-1.0 | HO-NDA-12.5M-1.0 | 12.5 | 1.0 | NG4 | 20.00 | 37.00 |
HO-NDA-12.5-1.3 | HO-NDA-12.5M-1.3 | 12.5 | 1.3 | NG4 | 20.00 | 37.00 |
HO-NDA-12.5-2.0 | HO-NDA-12.5M-2.0 | 12.5 | 2.0 | NG9 | 20.00 | 37.00 |
HO-NDA-12.5-3.0 | HO-NDA-12.5M-3.0 | 12.5 | 3.0 | NG9 | 20.00 | 37.00 |
HO-NDA-12.5-4.0 | HO-NDA-12.5M-4.0 | 12.5 | 4.0 | NG9 | 20.00 | 37.00 |
HO-NDA-12.5-5.0 | HO-NDA-12.5M-5.0 | 12.5 | 5.0 | NG9 | 20.00 | 37.00 |
HO-NDA-12.5-6.0 | HO-NDA-12.5M-6.0 | 12.5 | 6.0 | NG1 | 20.00 | 37.00 |
HO-NDA-25-0.1 | HO-NDA-25M-0.1 | 25 | 0.1 | NG11 | 36.00 | 56.00 |
HO-NDA-25-0.2 | HO-NDA-25M-0.2 | 25 | 0.2 | NG11 | 36.00 | 56.00 |
HO-NDA-25-0.3 | HO-NDA-25M-0.3 | 25 | 0.3 | NG4 | 36.00 | 56.00 |
HO-NDA-25-0.4 | HO-NDA-25M-0.4 | 25 | 0.4 | NG4 | 36.00 | 56.00 |
HO-NDA-25-0.5 | HO-NDA-25M-0.5 | 25 | 0.5 | NG4 | 36.00 | 56.00 |
HO-NDA-25-0.6 | HO-NDA-25M-0.6 | 25 | 0.6 | NG4 | 36.00 | 56.00 |
HO-NDA-25-1.0 | HO-NDA-25M-1.0 | 25 | 1.0 | NG4 | 36.00 | 56.00 |
HO-NDA-25-1.3 | HO-NDA-25M-1.3 | 25 | 1.3 | NG4 | 36.00 | 56.00 |
HO-NDA-25-2.0 | HO-NDA-25M-2.0 | 25 | 2.0 | NG9 | 36.00 | 56.00 |
HO-NDA-25-3.0 | HO-NDA-25M-3.0 | 25 | 3.0 | NG9 | 36.00 | 56.00 |
HO-NDA-25-4.0 | HO-NDA-25M-4.0 | 25 | 4.0 | NG9 | 36.00 | 56.00 |
HO-NDA-25-5.0 | HO-NDA-25M-5.0 | 25 | 5.0 | NG9 | 36.00 | 56.00 |
HO-NDA-25-6.0 | HO-NDA-25M-6.0 | 25 | 6.0 | NG1 | 36.00 | 56.00 |
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