Depolarization　is　one　of　important　factor　limits　the　output　extinction　ratio　of　polarization,　pulse　stability　and　energy　of　passively　Q-switched　Nd:YAG/Cr4+:YAG　laser,　especially　in　high　pump　energy　regime.　We　experimentally　investigate　the　output　extinction　ratio　of　polarization,　pulse　stability　and　energy　with　different　crystal　cuts　of　Nd:YAG　and　Cr4+:YAG.　We　demonstrate　that　linearly　polarized,　highly　stable　passively　Q-switched　output　can　be　greatly　enhanced　by　adopting　[100]-cut　Nd:YAG　crystal　as　the　gain　medium　and　[110]-cut　Cr4+:YAG　crystal　as　the　saturable　absorber.　The　output　pulse　energy　is　8.5　mJ,　repetition　frequency　is　100　Hz,　pulse　duration　is　13　ns,　extinction　ratio　of　polarization　is　higher　than　800:1　and　pulse　amplitude　instability　is　2.8%.　(C)　2014　Elsevier　B.V.　All　rights　reserved.