Quantum-optical coherence tomography with dispersion cancellation

Abstract

We propose a new technique, called quantum optical coherence tomography (QOCT), for carrying out tomographic measurements with dispersioncancelled resolution. The technique can also be used to extract the frequencydependent refractive index of the medium. QOCT makes use of a two-photon interferometer in which a swept delay permits a coincidence interferogram to be traced. The technique bears a resemblance to classical optical coherence tomography (OCT). However, it makes use of a nonclassical entangled twin-photon light source that permits measurements to be made at depths greater than those accessible via OCT, which suffers from the deleterious effects of sample dispersion. Aside from the dispersion cancellation, QOCT offers higher sensitivity than OCT as well as an enhancement of resolution by a factor of 2 for the same source bandwidth. QOCT and OCT are compared * teich@bu.edu † http://www.bu.edu/qil 1 using an idealized sample. 42.50.Dv, 42.65.Ky

Nonlinear optical signals and spectroscopy with quantum light

“…In the field of quantum-enhanced measurements, entanglement may be employed to enhance the precision of the measurement beyond the Heisenberg limit (Giovannetti et al, 2004(Giovannetti et al, , 2006Mitchell et al, 2004). Similarly, the spatial resolution may be enhanced in quantum imaging applications Pittman et al, 1995), quantum-optical coherence tomography (Abouraddy et al, 2002;Esposito, 2016;Nasr et al, 2003), as well as in quantum lithographic applications (Boto et al, 2000;D'Angelo et al, 2001).…”

“…Besides, their nonclassical bandwidth properties have long been recognized as a potential resource in various "quantum-enhanced" applications, where the quantum correlations shared between the photon pairs may offer an advantage. For example when one photon from an entangled pair is sent through a dispersive medium, the leading-order dispersion is compensated in photon coincidence measurements -an effect called dispersion cancellation (Abouraddy et al, 2002;Franson, 1992;Larchuk et al, 1995;Minaeva et al, 2009;Steinberg et al, 1992a,b). In the field of quantum-enhanced measurements, entanglement may be employed to enhance the precision of the measurement beyond the Heisenberg limit (Giovannetti et al, 2004(Giovannetti et al, , 2006Mitchell et al, 2004).…”

Phase-conjugate optical coherence tomography

“…At this juncture it is worth emphasizing the fundamental physical point revealed by the preceding analysis. The use of entangled biphotons and fourth-order interference measurement in an HOM interferometer enable Q-OCT's two performance advantages over C-OCT: a factor-of-two improvement in axial resolution and cancellation of evenorder dispersion [2,3]. Classical phase-sensitive light also produces an HOM dip with even-order dispersion cancellation, but this dip is essentially unobservable because it rides on a much stronger background term [4].…”

“…Abouraddy et al . [2] use Klyshko's advanced-wave interpretation [7] to account for the H * (−Ω)H(Ω) factor in the Q-OCT signature as the product of an actual sample illumination and a virtual sample illumination. In our PC-OCT imager, this same H * (−Ω)H(Ω) factor comes from the two sample illuminations, one before phase conjugation and one after.…”

“…Conventional OCT (C-OCT) uses classicalstate signal and reference beams, with a phase-insensitive cross-correlation, and measures their second-order interference in a Michelson interferometer [1]. Quantum OCT (Q-OCT) employs signal and reference beams in an entangled biphoton state, and measures their fourth-order interference in a Hong-Ou-Mandel (HOM) interferometer [2,3]. In comparison to C-OCT, Q-OCT offers the advantages of a two-fold improvement in axial resolution and even-order dispersion cancellation.…”