Infrared studies of single-crystal La2-xSrxCuO4-b and YBa2Cu307-6

Polarized infrared reflectance measurements are reported for crystals of La2s-SrxCuO4-6 and YBa2Cu307 -6. Free- carrier reflectance is observed in the copper oxide planes, and strong phonons are observed in the perpendicular direction. The interpretation of the infrared optical properties is discussed.