Due to its optical design, a beam always exits a Czerny-Turner monochromator in the angle corresponding to its f-number. Its irradiance thus decreases with increasing distance to the slit. Depending on the application, this can require a subsequent collimation. The question then is: Mirrors or lenses? If the monochromator is used as a tunable monochromatic light source, the chromatic aberration of simple plano-convex lenses is particularly disruptive. Achromats are better, but they are also only corrected for a certain wavelength range. Broadband applications demand the use of mirrors. This calls for (often multiple) beam deflection, which influences the unit dimension and requires a good mechanical alignment. Given this, a continuous linear beam guidance is almost impossible.
Our MSH monochromators/double monochromators now offer complete collimation optics which can easily be adapted to existing systems.
Based on two parabolic off-axis mirrors, a central pinhole and adjustable exit pupil, the collimator provides a parallel exit beam. By using different pinholes with various diameters, the quality of collimation vs. irradiance can be adapted to the application.