Electromagnetic field measuring apparatus, electromagnetic field measuring method used for the same, and non-transitory computer readable medium storing electromagnetic field measurement control program

An electromagnetic field measuring method comprising:

• a carrier signal light emitting process of emitting a laser beam having a predetermined frequency as a carrier signal light;
• a modulated light emitting process of generating a modulated light by modulating the carrier signal light at a predetermined local oscillation frequency, and emitting the modulated light;
• a signal light emitting process of generating a signal light by exposing the modulated light incident through a certain optical component to an electromagnetic field of a radio frequency band caused by an object to be measured and thereby modulating the modulated light, and emitting the signal light;
• an electric signal output process of outputting an electric signal having a same radio frequency band as the electromagnetic field based on the signal light incident through the optical component;
• a spectrum measurement process of measuring a spectrum of the electric signal;
• and
• an amplitude level ratio control process of controlling an amplitude level ratio between a carrier and a sideband contained in the signal light incident through the optical component to a fixed value based on the spectrum of the electric signal measured in the spectrum measurement process.

An electromagnetic field measuring apparatus comprising:

• a laser light source that emits a laser beam having a predetermined frequency as a carrier signal light;
• light modulation means for generating a modulated light by modulating the carrier signal light at a predetermined local oscillation frequency, and emitting the modulated light;
• a certain optical component;
• an electromagnetic field sensor that generates a signal light by exposing the modulated light incident through the optical component to an electromagnetic field of a radio frequency band caused by an object to be measured and thereby modulating the modulated light, and emits the signal light;
• an optical receiver that receives the signal light from the electromagnetic field sensor through the optical component and outputs an electric signal having a same radio frequency band as the electromagnetic field;
• a spectrum analyzer that measures a spectrum of the electric signal;
• and
• amplitude level ratio control means for controlling an amplitude level ratio between a carrier and a sideband contained in the signal light incident on the optical receiver to a fixed value based on the spectrum of the electric signal measured by the spectrum analyzer.