유니오텍 PPSLT (PERIODICALLY POLED STOICHIOMETRIC LITHIUM TANTALITE) Crystal. Periodic Poled SLT (PPSLT) is a leading QPM nonlinear optical material for frequency conversion over … PPSLT (PERIODICALLY POLED STOICHIOMETRIC LITHIUM TANTALITE) Crystal. Periodic Poled SLT (PPSLT) is a leading QPM nonlinear optical material for frequency conversion over …