An optical lens/detector arrangement has a monolithic detector layer on the radiation inlet side of a substrate and a monolithic radiation deflection device on the opposite side. The radiation entering the substrate through the radiation inlet side is reflected on the radiation deflection device in such a way that the reflected radiation impinges on the detector layer and is detected there. The radiation deflection device can also have a light deflecting and/or diffracting effect as well as its reflective action so that the impinging radiation is collected and focussed on a certain region of the detector layer.