Diffraction Grating. Mirror 3. Mirror 2. Half Mirror. Mirror 4. Reference. Cuvette. Sample. Filter. Mirror 1. Light Source Vis (Tungsten) Light Source UV (Deuterium/D2) Slit 1. Slit 2. Lens 1. Lens 2. Detector-1. Detector-2. Reference Beam. Sample Beam. 1a. 1b a. 6b. 7b. 7a. 5. I0. I.