Optical system design for wide range optical density measurements
This invention relates to optical cell geometry and to the arrangement of optical elements in an absorbance (at 200 nm to 50000 nm) detector. The invention allows to significantly expand the dynamic range of an optical density measuring instrument without affecting the signal to noise ratio. The invention also allows to enhance the precision of said instrument by eliminating the artifacts that arise from partial reflections of the incident beam, which occur on the passage of the beam through interfaces between different media.
1. An optical cell for optical density measurements at 200 nm to 50000 nm of solutions of radiation-absorbing samples comprising:
a flat entrance optical window and a non-flat exit optical window in direct contact with the sample;
wherein the windows are made of material(s) transparent to the electromagnetic radiation that is used to measure optical density of a sample;
wherein the non-flat exit optical window is convex on the side of the non-flat exit optical window in direct contact with the sample;
wherein the non-flat exit optical window is configured to create multiple, continuous, unequal path lengths for a beam of electromagnetic radiation passing through the sample.