Sensor, Method for Detecting The Presence and/or Concentration of an Analyte Using the Sensor, and Use of the Method

A method comprising:

• using a first mirror in a resonant cavity device in a sensing element to emit optical radiation at an initial power level;
• exposing a sensing layer in the sensing element to an analyte, thereby reducing a reflectivity of a second mirror in the resonant cavity device;
• in response to reducing the reflectivity of the sensing layer, using the first mirror of the resonant cavity device to emit optical radiation at a modified power level;
• and
• using a detector in the sensing element to detect the modified power level.

A sensor comprising:

• a number of sensing elements, each sensing element comprising:
• a resonant cavity device configured to emit optical radiation at an initial power level;
• a sensing layer exhibiting an initial refractive index;
• and
• a detector, wherein:
• the sensing layer is configured to absorb or adsorb an analyte and, in response to absorbing or adsorbing the analyte, exhibit a modified refractive index that differs from the initial refractive index;
• the resonant cavity device is further configured to, in response to the sensing layer absorbing or adsorbing the analyte, emit optical radiation at a modified power level based on the modified refractive index;
• and
• the detector is configured to detect the modified power level.