Oxide materials are integral parts of many high-temperature processes and applications. An accurate determination of their optical and radiative properties is essential to improve the accuracy of temperature measurements or to develop new materials in many sectors, including the glass and aerospace industries. However, these materials are often semi-transparent in much of the thermal radiation range, which complicates both the measurement and interpretation of their emittances. For this reason, the OR2T group at CEMHTI – CNRS Orléans has developed a powerful instrument compatible with semi-transparent materials up to 2500 K, including measurements at the melting point. The samples are heated by a 500 W CO₂ laser, whose signal is split to provide equal heating power on both sides of the sample, in order to minimize thermal gradients. Suitable beam-splitters and detectors are used to cover measurements from the far-infrared (250 µm) to the visible range. The sample temperature is determined using the Christiansen point, with a standard uncertainty estimated to be less than 1%. Emittance measurements can also be used to extract the temperature-dependent optical indices (n and k), as well as to study the underlying microscopic mechanisms responsible for thermal emission. The capabilities of the system are demonstrated using emittance data of homogeneous and heterogeneous oxide materials up to the melting point.