Circular Stepped ND Filters | SIMTRUM Photonics Store

Circular Stepped ND Filters can adjust the intensity of incoming light beam to be transmitted by rotating across different segments along its centre axis. The spectrum passes through will continue to maintain its neutral spectrum energy distribution. This filter is commonly used in laser and medical application. By combining two filters, fixed density attenuation effect across a greater area can be obtained. The spectral range of our filters features a wavelength of 250-2500nm.

B270 is a clear and colourless glass with high transparency for visible and near-infrared light. It almost free of bubbles and remains stable to the solarization effect that usually occurs when a material is constantly exposed to the sun or UV rays. Therefore, making it an ideal choice for 

general optical applications.

The level of attenuation is specified by Optical Density (OD) of the filter.

OD is defined as negative of the base 10 logarithm of the transmission coefficient,

The equation can be shown as:

OD= - Log10 (T/100)

Where T is transmission in percentage.

E.g. A Neutral Density Filter with T= 1% has OD of 2.

We are here for you!