Quantum Optical Coherence Tomography With Thermal Light Source

Optical Coherence Tomography(OCT) is an important imaging technology.Thetechnology is first proposed in the paper published in Science in1991by Huang etal.,.Its basic principle is weak coherent optical interferometer (Michelsoninterferometer).As higher and higher requirement,dispersion effects of wide spectrumlight source appeared in front of people.Thereupon,Quantum Optical CoherenceTomography(QOCT) appeared for dispersion-cancelled.QOCT is proposed by Teich’sgroup in the Boston University in2002.Its basic principle is nonclassic light source ofOCT.As the rise of QOCT and researching on thermal light correlation propertiesdeeply by many scientists,especially ghost imaging and ghost interference experimentcompleted successfully by thermal light instead of entangled light,prompted us toQOCT with thermal light produced great interest. In2006,L.-A. Wu’s group whowork in the institute of physics,Chinese academy of science put forward true-thermallight of QOCT scheme for the first time.This article is based on the scheme putting forward QOCT with pseudo-thermallight which bases on longitudinal HBT experiment and using second-orderlongitudinal correlation properties of pseudo-thermal light to imaging.Pseudo-thermallight’s spectral width is narrow and reducing influence of dispersion is its naturaladvantages.Comparing to QOCT with entangled light,QOCT with thermal has thefollowing advantages:don’t need coherent light source;no lens imaging;not affectedby turbulence and turbid air;suitable to any wavelength;its longitudinal resolution isclassic OCT’s (1/2)1/2when the spectrum width of light source is the same.Firstly,weresearch on second-order longitudinal coherent nature of pseudo-thermal light.wefound that the resolution that two detectors reverse scanning is higher than theresolution that fixed a detector,scanning with another detector,but the contrast rationdoes not change.Then using the samples to experimentalize by QOCT withpseudo-thermal light that measuring the distance between the two mirrors.Foundingthat mirror reflectivity is influence to the contrat ration,that larger the reflectivity is,higher the contrat ration is,and no influence to resolution.Results with thetheoretical expectations conform to good.