A thermopile sensor for detection of infrared radiation in a measurement wavelength range having a sensor substrate in which a cavity is formed, a diaphragm formed on the sensor substrate above the cavity, at least one thermopile structure formed in, on, or below the diaphragm, having at least one thermopile pair of mutually contacted thermopile legs, where the two thermopile legs are made of doped semiconductor materials having different Seebeck coefficients, and at least one insulating intermediate layer formed between the thermopile legs. A layer system having at least the two thermopile legs and at least the insulating intermediate layer is formed above the lower cavity and has multibeam interference for IR radiation in the measurement wavelength range, absorbing a portion of the IR radiation and at least partially reducing the reflection.