Abstract: There is presented a spectroscopic apparatus and method wherein an input light source that inputs pump light to a photon pair source. The photon pair source converts pump photons into signal and idler photon pairs. The photon pair source is, in some of examples described herein, tuneable so that the wavelength of the signal and idler photons can be changed by application of a tuning means. At least one of the signal and idler photons is made incident upon a medium under test. A heralding detection apparatus is used to detect any signal and idler photons output from the spectroscopy apparatus, wherein at least one of the photons of the pair has interacted with or been operated upon by the medium under test.

Abstract: There is presented a spectroscopic apparatus and method wherein an input light source that inputs pump light to a photon pair source. The photon pair source converts pump photons into signal and idler photon pairs. The photon pair source is, in some of examples described herein, tuneable so that the wavelength of the signal and idler photons can be changed by application of a tuning means. At least one of the signal and idler photons is made incident upon a medium under test. A heralding detection apparatus is used to detect any signal and idler photons output from the spectroscopy apparatus, wherein at least one of the photons of the pair has interacted with or been operated upon by the medium under test.

Abstract: An integrated optical device and method for generating photons by manipulating path entanglement is provided. An integrated optical splitter splits pump light between two interferometer arms wherein each arm comprises a substantially identical photon pair source configured to be able to convert at least one pump light photon into a signal and idler photon pair. An integrated optical combiner device in optical communication with a first and a second optical output path interferes light from the first and second arms and outputs the signal and idler photons by bunching the signal and idler photons together in one of the optical output paths, or anti-bunching the signal photon in one output path and the corresponding idler photon in the other optical output path.

Abstract: An integrated optical device and method for generating photons by manipulating path entanglement is provided. An integrated optical splitter splits pump light between two interferometer arms wherein each arm comprises a substantially identical photon pair source configured to be able to convert at least one pump light photon into a signal and idler photon pair. An integrated optical combiner device in optical communication with a first and a second optical output path interferes light from the first and second arms and outputs the signal and idler photons by bunching the signal and idler photons together in one of the optical output paths, or anti-bunching the signal photon in one output path and the corresponding idler photon in the other optical output path.