Light-trapping　structures　are　fabricated　on　crystalline　(100)　silicon　(c-Si)　surfaces　by　picosecond　(ps)　laser　irradiation　followed　by　chemical　etching.　First,　1064-nm　ps　laser　scanning　is　used　to　form　micropore　arrays　on　c-Si.　The　ps　laser　processing　causes　little　reconsolidation　of　the　silicon　surface,　which　is　beneficial　to　achieve　precise　etching.　Control　of　the　laser　scanning　interval,　number　of　scans,　and　etching　time　gives　a　micro-nano　hierarchical　structure.　In　this　hierarchical　structure,　the　average　diameter　of　the　micropores　is　25　to　30　mu　m,　while　the　size　of　the　finer　nanostructures　on　the　micropore　inner　walls　ranges　from　dozens　to　hundreds　of　nanometers.　Unlike　traditional　laser　texturing　techniques,　the　whole　laser　process　is　carried　out　without　mask　and　photolithography.　The　reflectance　of　the　c-Si　surface　with　a　micro-nano　hierarchical　structure　is　as　low　as　6%　in　the　wavelength　range　from　400　to　1000　nm　without　coating.　Moreover,　the　samples　also　show　good　hydrophobicity.　This　is　a　potential　method　to　fabricate　economical　antireflective　structures　that　are　ideal　for　applications　in　c-Si　solar　cells　and　self-cleaning　c-Si　microelectronic　devices.　(C)　2015　Society　of　Photo-Optical　Instrumentation　Engineers　(SPIE)