Abstract: It is an object of the invention to improve processes, apparatuses and systems for measuring a measured variable. To this end, a measured variable is measured in a measuring process on the basis of an NV center as a quantum sensor. The NV center has a plurality of quantum states and is optically excitable on the basis of an occupancy of one of the quantum states into at least one excited state of the quantum states by means of an excitation light. The at least one excited state can decay at least with emission of emission light of the NV center. In the measuring process, the NV center is irradiated by the excitation light, the excitation light having a time periodic modulation, and a respective occupancy probability and/or a respective lifetime of the quantum states depending on the measured variable and the excitation light.

Abstract: It is an object of the invention to improve processes, apparatuses and systems for measuring a measured variable. To this end, a measured variable is measured in a measuring process on the basis of an NV center as a quantum sensor. The NV center has a plurality of quantum states and is optically excitable on the basis of an occupancy of one of the quantum states into at least one excited state of the quantum states by means of an excitation light. The at least one excited state can decay at least with emission of emission light of the NV center. In the measuring process, the NV center is irradiated by the excitation light, the excitation light having a time periodic modulation, and a respective occupancy probability and/or a respective lifetime of the quantum states depending on the measured variable and the excitation light.

Abstract: A magnetometer comprising: a sensor formed of diamond material and comprising a plurality of spin centers; a microwave source configured to subject the plurality of spin centers to microwave pulses; a light source configured to subject the plurality of spin centers to light pulses; and a detector configured to detect a fluorescent output signal emitted from the plurality of spin centers, wherein the magnetometer is configured to integrate the fluorescent output signal over a signal averaging time and process the fluorescent output signal such that a standard deviation of the fluorescent output signal decreases with the square root of the signal averaging time over a time period which spans at least two orders of magnitude in the signal averaging time to achieve a standard deviation of less than 100 picotesla.

Abstract: A magnetometer comprising: a sensor formed of diamond material and comprising a plurality of spin centres; a microwave source configured to subject the plurality of spin centres to microwave pulses; a light source configured to subject the plurality of spin centres to light pulses; and a detector configured to detect a fluorescent output signal emitted from the plurality of spin centres, wherein the magnetometer is configured to integrate the fluorescent output signal over a signal averaging time and process the fluorescent output signal such that a standard deviation of the fluorescent output signal decreases with the square root of the signal averaging time over a time period which spans at least two orders of magnitude in the signal averaging time to achieve a standard deviation of less than 100 picotesla.