A vehicle engine is provided that includes an exhaust manifold configured to emit a first emission. A heat shield is positioned proximate the exhaust manifold and has a shield substrate defining an aperture. An indicator is positioned over the aperture with a support substrate and a semiconductor layer. The semiconductor layer is configured to absorb the first emission and emit a second emission.

A vehicle engine is provided that includes an exhaust manifold configured to emit a first emission. A heat shield is positioned proximate the exhaust manifold and has a shield substrate defining an aperture. An indicator is positioned over the aperture with a support substrate and a semiconductor layer. The semiconductor layer is configured to absorb the first emission and emit a second emission.

The disclosure relates to an optical method for temperature sensing utilizing a temperature sensing material. In an embodiment the gas stream, liquid, or solid has a temperature greater than about 500 C. The temperature sensing material is comprised of metallic nanoparticles dispersed in a dielectric matrix. The metallic nanoparticles have an electronic conductivity greater than approximately 10.sup.1 S/cm at the temperature of the temperature sensing material. The dielectric matrix has an electronic conductivity at least two orders of magnitude less than the dispersed metallic nanoparticles at the temperature of the temperature sensing material. In some embodiments, the chemical composition of a gas stream or liquid is simultaneously monitored by optical signal shifts through multiple or broadband wavelength interrogation approaches. In some embodiments, the dielectric matrix provides additional functionality due to a temperature dependent band-edge, an optimized chemical sensing response, or an optimized refractive index of the temperature sensing material for integration with optical waveguides.

Various techniques are provided to utilize nanostructures for process monitoring and feedback control. In one example, a method includes forming a layer of material including nanostructures distributed therein. Each nanostructure includes a quantum dot and a shell encompassing the quantum dot. The shells and quantum dots are configured to emit a first and second wavelength, respectively, in response to an excitation signal. The method further includes applying the excitation signal to at least a portion of the layer of material. The method further includes detecting an emitted signal from the portion of the layer of material, where the emitted signal is provided by at least a subset of the nanostructures in response to the excitation signal. The method further includes determining whether a manufacturing characteristic has been satisfied based at least on a wavelength of the emitted signal. Related systems and products are also provided.