Abstract: A peak position measurement offset is determined in a two-dimensional optical spectrum. A plurality of peaks are identified that appear in both a spectrum obtained from a reference material at known conditions and a spectrum obtained from a sample of interest. The peak position measurement offset is determined by a comparison of a pattern formed by peak positions of the plurality of identified peaks in the spectrum obtained from the sample of interest against the plurality of identified peaks in the spectrum obtained from the reference material.

Abstract: An optical system is provided which comprises: a light source (1) for emitting light beam; an optical main axis; an optical shaping element (2) for shaping a light beam facing the light source (1) and directly adjacent to the light source (1), wherein the optical shaping element (2) includes a first freeform surface facing the light source (1), the light beam is shaped by means of the first freeform surface of the optical shaping element (2) in such a way that light intensity of the light beam has a flat-top profile on a first axis which is perpendicular to the optical main axis. With this optical system, a desirable light intensity profile can be achieved by using only a single optical element. Moreover, a flow cytometer including this optical system is provided.

Abstract: An optical system is provided which comprises: a light source (1) for emitting light beam; an optical main axis; an optical shaping element (2) for shaping a light beam facing the light source (1) and directly adjacent to the light source (1), wherein the optical shaping element (2) includes a first freeform surface facing the light source (1), the light beam is shaped by means of the first freeform surface of the optical shaping element (2) in such a way that light intensity of the light beam has a flat-top profile on a first axis which is perpendicular to the optical main axis. With this optical system, a desirable light intensity profile can be achieved by using only a single optical element. Moreover, a flow cytometer including this optical system is provided.