NV-center-based microwave-free quantum sensor and uses and characteristics thereof

A sensor system, comprising:

• a sensor element, wherein:
• the sensor element comprises or can be equal to a substrate;
• a volume of space can be selected in the substrate;
• the substrate comprises in the selected volume of space a group of at least two paramagnetic centers;
• the sensor system comprises a pump radiation source for exciting a fluorescence radiation of the group of at least two paramagnetic centers;
• the fluorescence radiation has a fluorescence radiation wavelength (Ifl);
• the sensor system comprises a radiation detector for detecting and evaluating the fluorescence radiation;
• external dimensions of the selected volume of space do not exceed twice the fluorescence radiation wavelength (Ifl);
• the volume of space is larger than half a pump radiation wavelength (Ipmp) of a pump radiation to a third power of the pump radiation source;
• the sensor system generating and/or providing a measured value by the pump radiation source and the radiation detector as a function of the fluorescence radiation of the group of at least two paramagnetic centers;
• the fluorescence radiation depends on a physical parameter;
• the measured value depends on the physical parameter;
• the measured value is used as a measured value of the physical parameter;
• and
• a concentration of paramagnetic centers of the group of at least two paramagnetic centers, generated by irradiation with particles in the volume of space is on average greater than 10 ppm relative to a number of atoms of the substrate per unit volume in the volume of space.