Abstract: A two-dimensional, AC-coupled, wide dynamic range, mosaic infrared sensor is realized by apparatus that divides incoming infrared radiation into two equal beams. Each beam is received with or without optical concentration by an infrared detector array consisting of a multiplicity of spaced, parallel columns of electrically insulated, independently wired infrared detector elements. The detector element column widths of each detector array are substantially equal to the intercolumn spaces of the other detector array and the columns of each are optically aligned with the intercolumn spaces of the other.