a thermal printer is disclosed which is particularly suitable for making slide transparencies . the printer includes a laser which provides the necessary energy to effect a transfer of dye from a donor element to a receiver element . in order to insure the transfer of dye from the donor at a suitable resolution and with sufficient speed , two relatively high - powered single transverse mode lasers are used . the beam from one of the lasers is passed through a half - wave plate , and the beam is then combined with the beam from the other laser by a polarization beam splitter . the combined beam is passed through suitable optics and is scanned onto the receiver element by a galvonometer .