Submicron axial resolution in an ultrabroadband two-photon interferometer using superconducting single-photon detectors

Magued B Nasr,Gregory N Goltsman,Malvin C Teich,Bahaa E Saleh,Olga Minaeva,Alexander V Sergienko

doi:10.1364/oe.16.015104

Abstract

We generate ultrabroadband biphotons via the process of spontaneous parametric down-conversion in a quasi-phase-matched nonlinear grating that has a linearly chirped poling period. Using these biphotons in conjunction with superconducting single-photon detectors (SSPDs), we measure the narrowest Hong-Ou-Mandel dip to date in a two-photon interferometer, having a full width at half maximum (FWHM) of approximately 5.7 fsec. This FWHM corresponds to a quantum optical coherence tomography (QOCT) axial resolution of 0.85 ?m. Our results indicate that a high flux of nonoverlapping biphotons may be generated, as required in many applications of nonclassical light.

Highlights

We generate ultrabroadband biphotons via the process of spontaneous parametric down-conversion in a quasi-phase-matched nonlinear grating that has a linearly chirped poling period. Using these biphotons in conjunction with superconducting single-photon detectors (SSPDs), we measure the narrowest Hong-Ou-Mandel dip to date in a two-photon interferometer, having a full width at half maximum (FWHM) of ≈ 5.7 fsec. This FWHM corresponds to a quantum optical coherence tomography (QOCT) axial resolution of 0.85 μm
Our results indicate that a high flux of nonoverlapping biphotons may be generated, as required in many applications of nonclassical light
In 1987, Hong, Ou, and Mandel (HOM) introduced a new interferometric technique for measuring the subpicosecond temporal separation between two indistinguishable photons [1]. Their approach has since been employed in various applications; these include the generation of entangled states [2, 3], the measurement of the degree of indistinguishability between photons from a single-photon source [4, 5], and quantum optical coherence tomography (QOCT) [6, 7]

Summary

Introduction

Using these biphotons in conjunction with superconducting single-photon detectors (SSPDs), we measure the narrowest Hong-Ou-Mandel dip to date in a two-photon interferometer, having a full width at half maximum (FWHM) of ≈ 5.7 fsec. Their approach has since been employed in various applications; these include the generation of entangled states [2, 3], the measurement of the degree of indistinguishability between photons from a single-photon source [4, 5], and quantum optical coherence tomography (QOCT) [6, 7].

Results

Conclusion