A method of measuring a temperature of a thermally-insulated, high temperature system. The method includes directing a first electromagnetic energy into the high temperature system so that the first electromagnetic energy may cause multi-photon ionization of a molecular or atomic species within the high temperature system. A second electromagnetic energy resulting from the multi-photon ionization is detected through a thermally-insulating wall of the high temperature system. The detected second electromagnetic energy is related to a temperature within the high temperature system.

A method of measuring a temperature of a thermally-insulated, high temperature system. The method includes directing a first electromagnetic energy into the high temperature system so that the first electromagnetic energy may cause multi-photon ionization of a molecular or atomic species within the high temperature system. A second electromagnetic energy resulting from the multi-photon ionization is detected through a thermally-insulating wall of the high temperature system. The detected second electromagnetic energy is related to a temperature within the high temperature system.

A method of measuring a temperature of a thermally-insulated, high temperature system. The method includes directing a first electromagnetic energy into the high temperature system so that the first electromagnetic energy may cause multi-photon ionization of a molecular or atomic species within the high temperature system. A second electromagnetic energy resulting from the multi-photon ionization is detected through a thermally-insulating wall of the high temperature system. The detected second electromagnetic energy is related to a temperature within the high temperature system.

A method of measuring a temperature of a thermally-insulated, high temperature system. The method includes directing a first electromagnetic energy into the high temperature system so that the first electromagnetic energy may cause multi-photon ionization of a molecular or atomic species within the high temperature system. A second electromagnetic energy resulting from the multi-photon ionization is detected through a thermally-insulating wall of the high temperature system. The detected second electromagnetic energy is related to a temperature within the high temperature system.