The invention relates to the detection of sparks in a channel where material flows. A spark sensing device is positioned in connection with channel where material flows in a flowing direction. The spark sensing device comprises a sensor element and an optical element that transfers a radiation of a spark to the sensor element. The optical element is made of optically transparent material. The optical element is such that it shapes the collection beam of the sensor element to be asymmetrical whereby the viewing angle of the sensor element is wider in a direction transverse to the flowing direction than in the flowing direction.

A detection device comprises a chip holder, a light source, a light-guide rod, a wavelength separation filter, and an optical sensor. Given the relationship between the angle of incidence and light intensity of fluorescence on a light reception surface of the optical sensor, the optical transmittance of the wavelength separation filter at the dominant wavelength of the rays of fluorescence incident on the light reception surface at a peak angle of incidence at which the light intensity is the highest is greater than the optical transmittance of the wavelength separation filter at the dominant wavelength of the rays of excitation light incident on the light reception surface at the peak angle of incidence and is higher than the optical transmittance of the wavelength separation filter at the dominant wavelength of the rays of fluorescence incident on the light reception surface at an angle of incidence of 0 DEG.

Embodiments herein relate to combinations for use in light energy excitation. Light energy, according to one example, can be directed toward a detector surface that can support biological or chemical samples.

A device for examining material samples via electromagnetic radiation. The device comprises a lighting unit for generating the electromagnetic radiation with at least two radiation sources. The radiation of the radiation sources can be selectively directed onto the material sample. The device further comprises a detection unit having at least two detectors for capturing electromagnetic radiation emanating from the material sample. A deflection element is arranged in the detection unit, via which the electromagnetic radiation emanating from the material sample can be selectively deflected onto one of the detectors. This deflection element comprises a mirror, via which the radiation emanating from the material sample can be selectively deflected onto one of the detectors. The mirror is rotated about an axis extending substantially perpendicular to the optical axes of the detectors.

There is set forth herein a light energy exciter that can include one or more light sources. A light energy exciter can emit excitation light directed toward a detector surface that can support biological or chemical samples.