Ghost Metrology with Classical Light – The Story Continues: Ghost Spectroscopy and Ghost Polarimetry

摘要

Ghost metrology is a measurement modality exploiting correlations of photons. At ICTON 2017 [1], we had demonstrated ghost imaging by using a novel, extremely compact superluminescent diode source based on Amplified Spontaneous Emission and exhibiting photon bunching. Here, we now demonstrate that amplified spontaneous emission light emitted both by a spectrally broad-band semiconductor-based superluminescent diode and an erbium-doped fibre amplifier (EDFA) exhibit spectral photon correlations in the spirit of the Hanbury-Brown & Twiss (HBT) experiment, however now in the spectral domain. We then apply these spectral photon correlations within two proof-of-principal ghost spectroscopy experiments, one at an absorption band of trichloromethane (chloroform) at 1214 nm and another one at 1533nm at acetylene (C2H2) reproducing the characteristic absorption features. This ghost spectroscopy work fills the gap of a hitherto missing analogy between the spatial and the spectral domain in classical ghost modalities. Finally, by exploiting polarization correlations of light from an EDFA we succeed in reconstructing a hidden, camouflaged polarization in a ghost polarimetry experiment in close analogy to ghost imaging and ghost spectroscopy. Via these successfully demonstrated results, we are contributing towards a broader dissemination of correlated photon ghost modalities, hence paving the way towards more applications which exploit their favourable advantages.