In an embodiment, a method comprises: configuring a direct conversion compound semiconductor sensor over a first surface of a readout integrated circuit, IC, comprising two surfaces, each surface comprising solder material on the surface; illuminating the solder material with an infra-red laser such that the solder material on the readout IC melts and forms solder joints between the readout IC and the direct conversion compound semiconductor sensor; configuring a substrate over a second surface of the readout IC comprising solder material; and illuminating the solder material of the second surface with the infra-red laser such that the solder material on the readout IC melts and electrically connects the readout IC with the substrate. In other embodiments, a high frequency radiation detector and an imaging apparatus are discussed.