Nova Phase manufactures a variety of optical filters utilizing our in-house fabrication and coating equipment. We have standard lines of colored filter glass as well as absorptive and reflective neutral density filters. We recently added step and continuously variable optical filters to our standard product listing. Because we have full fabrication and coating facilities in-house, we can easily customize all of our standard products.

New Step and Variable Filters now available.

Our Absorptive ND Filters are manufactured from a family of Schott glasses that have varying internal absorption coefficients. By using three different glasses (each with a unique absorption) that are spectrally flat and by differing filter thicknesses we are able to manufacture this series of neutral density filters. They are ideal for low power applications and the absorptive glass eliminates multiple reflections.

These metal coated (Inconel) glass ND filters provide a uniform attenuation over a broad spectral range. The "optical density" is defined by the following equation: D=log₁₀(¹/_T), or T=10^-D. The Inconel film is a very hard metallic alloy that is resistant to aging under normal conditions. The Inconel coating will oxidize at elevated temperatures: it is recommended that these ND filters only be used at temperatures below 100°C.

These filters use different Schott colored filter glass for a wide variety of applications. Band pass filters allow required ranges to selectively pass through, long pass filters block unwanted shorter wavelength ranges and short pass filters block unwanted longer wavelength ranges. They are available 25.4mm in diameter and 50.8mm square from a large variety of Schott substrates.

Our stepped filters have an ND coating on the front with no coating on the back. They are coated in various steps; please see the chart below for step and transmission details. The Optical Density (OD) is defined as follows:

D = log₁₀(¹/_T), or T = 10^-D



Steps for coating 1: 0.04, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 1.0
Steps for coating 3: 0.04, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0
Steps for coating 4: 0.04, 0.2, 0.4, 0.6, 0.8, 1.0, 2.0, 3.0

Our continuously variable filters have an ND coating on the front with no coating on the back. They are coated through a full 270° and provide linear, adjustable attenuation by rotation. The Optical Density (OD) is defined as follows:

D = log₁₀(¹/_T), or T = 10^-D