Infrared spectroscopy with visible light

摘要: The refractive index and absorption coefficient of a medium in the infrared range are measured using visible spectral components. technique relies on nonlinear interference photons, produced by down-conversion. Spectral measurements optical provide unique fingerprints materials, which useful for material analysis, environmental sensing health diagnostics1. Current spectroscopy techniques require use equipment suited operation range, components face challenges inferior performance high cost. Here, we develop that allows visible-spectral-range is based via spontaneous parametric down conversion2,3. intensity pattern photon depends phase an travelling through medium. This to be determined from photons. can substitute and/or complement conventional refractometry techniques, as it uses well-developed range.