IR absorbing water filters are used to protect optical elements from the very intense IR heat delivered by the KiloArc™ illuminator. These water jacketed filters are necessary because the KiloArc™ delivers too much light and heat for a simple “hot mirror” to handle. These cylindrical metal devices are filled with water or some other IR absorbing liquid, such as copper sulfate, and have two quartz windows on either end to allow light to transmit through the absorbing solution. The cylindrical walls are water jacketed to allow cooling water to be circulated around the IR absorbing solution itself to keep it from overheating.
There are two OBB IR absorbing water filters to choose from. There is a lower cost aluminum filter that can only be filled with distilled water and there is a stainless steel filter that can be filled with distilled water, copper sulfate other IR absorbing liquids.
Distilled water is an excellent UV-Vis-NIR transmitter and IR absorber. It will transmit most of the light above 200 nm and absorb almost 100% of the light above 1,000 nm.
In addition to being used on a stand-alone basis, OBB’s IR absorbing water filters can be mounted directly inside our longer f/4.5 light shield adapter tubes which are used to couple the KiloArc™ and PowerArc™ illuminators directly to our f/4 monochromators to make a complete tunable illuminator. The Tunable KiloArc™ comes standard with an aluminum IR filter to help prevent thermal damage to the optical elements inside the monochromator.
There is an optional filter mount that can be attached to the output side of either IR absorbing water filter to allow for multiple 2” square filters to be held.