RESUMO
We introduce a method for measuring a periodic structure, particularly a grating period. The method is based on the high-precision laser Talbot effect. The combination of a rubidium-locked external cavity diode laser and the Talbot interferometer provides an excellent and simple tool for this purpose. Some experimental results are provided to demonstrate the approach.
RESUMO
We demonstrate the quantum Talbot effect using a beam of single photons produced by parametric down conversion. In contrast to the previous works, we use a programmable spatial light modulator to behave as a diffraction grating. Thus, the investigation of the Talbot diffraction patterns under the variation of grating structure can be easily performed. The influence of spectral bandwidth of the down-converted photons on the diffraction pattern is also investigated. A theoretical model based on the wave nature of photons is presented to explain the Talbot diffraction patterns under varying conditions. The measured diffraction patterns are in good agreement with the theoretical prediction. We are convinced that our study improves the understanding of the quantum Talbot effect.