With　the　aim　to　lower　the　surface　roughnesses　of　etched　samples　and　the　etching　threshold　fluence　of　a　direct　laser　irradiation　source　and　to　raise　the　yield　of　micro-optical　elements,　a　laser　induced　backside　dry　etching　technique　with　the　assistance　of　a　solid　medium　as　the　absorbed　layer　was　proposed　to　fabricate　transparent　dielectric　materials　by　direct　laser　irradiation.　By　using　an　alumina　ceramic　wafer　(Al2O3　in　95%,　surface　roughness　less　than　500　nm)　as　the　absorber,　a　2D　transmittance　grating　in　a　micro　size　binary　Diffractive　Optical　Element　(DOE)　was　fabricated　on　the　fused　silica　with　a　thickness　of　3.2　mm　by　the　1064　nm　Ytterbium　Doped　Fiber　(YDF)　laser.　And　then,　the　etching　parameter　curves　were　fitted　and　the　effect　of　laser　energy　density　on　the　parameters　was　discussed.　Finally,　the　diffraction　patterns　of　micro　structure　were　observed　to　examine　the　features　of　binary　DOE.　According　to　the　measured　results,　the　binary　transmittance　grating　shows　its　grating　constant　in　25　μm,　the　depth　of　trench　in　4.2　μm,　and　the　RMS　roughness　of　the　trench　bottom　below　40　nm.　Furthermore,　the　etching　threshold　influence　is　estimated　below　7.66　J/cm2.　These　results　are　much　lower　than　those　of　the　etching　without　any　absorbers.