Optical apparatus includes a beam source, which is configured to generate an optical beam having a pattern imposed thereon. A projection lens is configured to receive and project the optical beam so as to cast the pattern onto a first area in space having a first angular extent. A field multiplier is interposed between the projection lens and the first area and is configured to expand the projected optical beam so as to cast the pattern onto a second area in space having a second angular extent that is at least 50% greater than the first angular extent.