Optical measurement device

An optical measurement device for determining a property of an ambient environment comprising:

• a plasmonic sensing element configured to, when illuminated with electromagnetic radiation, exhibit a plasmonic resonance condition being dependent on the property of the ambient environment, wherein the plasmonic resonance condition is a localized surface plasmon resonance condition;
• a first light sensor;
• a second light sensor;
• a first light source arranged to simultaneously illuminate the first light sensor and the second light sensor, wherein the first light sensor is illuminated by the first light source via the plasmonic sensing element;
• a second light source arranged to simultaneously illuminate the first light sensor and the second light sensor, wherein the first light sensor is not illuminated by the second light source via the plasmonic sensing element;
• and
• circuitry configured to execute:
• a control function configured to control the first light source (130) and the second light source to alternately illuminate the first and second light sensors,
• a first receive function configured to receive a measurement signal from the first light sensor pertaining to light emitted by the first light source, and a first source signal from the second light sensor pertaining to light emitted by the first light source,
• a second receive function configured to receive a reference signal from the first light sensor pertaining to light emitted by the second light source, and a second source signal from the second light sensor pertaining to light emitted by the second light source, and
• a determination function configured to determine the property of the ambient environment by comparing the measurement signal and the reference signal, and
• the control function being further configured to control the first light source and the second light source, using the first source signal and the second source signal, such that a relation of the intensities of light emitted by the first light source and the second light source is constant over time.