Measurement device and measurement method

A measurement device comprising:

• a magnetic resonance member in which an electron spin quantum state changes in response to a measured field and in which an electron spin quantum operation is performed by using a microwave;
• a high frequency magnetic field generator that performs the electron spin quantum operation of the magnetic resonance member by using the microwave;
• a light emitting device that emits excitation light to irradiate the magnetic resonance member;
• a fluorescence light receiving device that receives fluorescence emitted by the magnetic resonance member in response to the excitation light and generates a fluorescence sensor signal corresponding to an intensity of the fluorescence;
• a CMR arithmetic part that performs common mode rejection with respect to the fluorescence sensor signal based on a reference light sensor signal and generates a CMR signal based on the common mode rejection, the reference light sensor signal being generated by receiving reference light, the reference light being obtained by branching the excitation light;
• a first analog/digital converter that digitizes the CMR signal;
• a second analog/digital converter that digitizes a reference light sensor signal that is generated by receiving reference light, the reference light being obtained by branching the excitation light;
• and
• an arithmetic processing device that generates a detection signal based on the digitized CMR signal and the digitized reference light sensor signal and derives a measurement value of the measured field based on the detection signal,
• wherein the CMR arithmetic part performs the common mode rejection in consideration of nonlinearity of a level of the fluorescence sensor signal corresponding to an amount of the excitation light, and
• the arithmetic processing device performs digital filter processing for noise removal with respect to the digitized CMR signal or the detection signal.