Quantum Imaging with Undetected Photons
The method of quantum imaging with undetected photons („QUIP“) allows to take images from objects without the need of detecting the light, being scattered from the object.
Quantum imaging with undetected photons is achieved by first splitting up a primary beam of photons into two separate beams of entangled photons having different wavelengths.
The two split-up beams are now themselves splitted up into two quantum-entangled split-up beams of different wave-length, whereat each one of these split-up beams of second generation has a wavelength of one of the split-up beams of the first splitting up. The split-up beams of first and second generation having the same wavelength are now merged and superposed so that their photons are now no longer distinguishable from each other. Due to the entanglement of the „combination-beams“ being acquired this way and having different wavelengths from each other, the behaviour of the photons of one of the beams can be determined by measuring the photons of the other beam – while both combination-beams, being entangled with each other and having different wavelengths. The object which is to be investigated will be illuminated with one of the combination-beams and the other combination-beam will be „analysed“. By doing so an object is being illuminated with one wavelength and the detection of the „result“ of the illumination will take place at another wavelength.
Hence, the method is based upon the emission of photon pairs from two coherent SPDC processes and spatial correlation within the photon pairs. The image is developing as interference pattern in one of the two beams, whereat the object is illuminated by the other beam. It is not necessary to detect the „object-beam“, because its behaviour can be derived from the „detection-beam“ at a different wavelength, due to their entanglement with each other.
Images & Videos
The technology enables to illuminate an object with one wavelength and detect the result of illumination at a different wavelength.
The method is opening the metrological application of frequency domains for which there are no suitable detectors existing. Because it is applicable independently from the original ferquency, basically the whole domain of wavelengths of electromagnetic radiation may be used with the method.
With respect to imaging the method for example offers the advantage towards the OPA-method (Optical Parametric Amplification) that for illuminating the object no coherent object-beam of the „illumination-wavelength“ is necessary. The method presented here also does not require stimulated nonlinear processes in forming the illumination beam, so that it can work with lower intensity, which is of great importance for sensitive probes.
Scope of application
The technology provides unknown opportunities in the areas of imaging, spectroscopy, photometry and other research methods being based on electromagnetic radiation.
The method may be used for investigations in the area of mid-infrared (MIR), for example for performing medical imaging (cancer diagnosis). Imaging in the spectral area of MIR is also highly relevant for investigation of historical exhibits, for example historical paintings.
Proof of concept
- EP EP 2 887 137 B1 granted
- US US 9,557,262 B2 granted
KeywordsQuantum entanglement, frequence split-up, imaging, medical imaging, cancer diagnosis, spectroscopy, photometry