The invention relates to a detector (110) for optical detection comprising a circuit carrier (130) designed to carry at least one layer, wherein the circuit carrier (130) is or comprises a printed circuit board (132); a reflective layer (138), the reflective layer (138) being placed on a partition of the circuit carrier (130), wherein the reflective layer (138) is designed to reflect the incident light beam (120), thereby generating at least one reflected light beam (124); a substrate layer (114), the substrate layer (114) being directly or indirectly adjacent to the reflective layer (138), wherein the substrate layer (114) is at least partially transparent with respect to the incident light beam (120); a sensor layer (122), the sensor layer (122) being placed on the substrate layer (114), wherein the sensor layer (122) is designed to generate at least one sensor signal in a manner dependent on an illumination of the sensor layer (122) by the incident light beam and the reflected light beam (124); and an evaluation device (150) designed to generate at least one item of information by evaluating the sensor signal; and at least two individual electrical contacts (148, 148′) contacting the sensor layer (122), wherein the electrical contacts (148, 148′) are designed to transmit the sensor signal via the circuit carrier (130) to the evaluation device (150). The detector (110) constitutes a detector for detecting optical radiation, especially within the infrared spectral range, specifically with regard to sensing at least one of transmissivity, absorption, emission and reflectivity, being capable of avoiding a loss of incident light.