8 research outputs found
HIgh-Noon States with High Flux of Photons Using coherent Beam Stimulated Non-Collinear Parametric Down Conversion
We show how to reach high fidelity NOON states with a high count rate inside
optical interferometers. Recently it has been shown that by mixing squeezed and
coherent light at a beamsplitter it is possible to generate NOON states of
arbitrary N with a fidelity as high as 94%. (Afek I. et al. Science 328, 879
(2010)). The scheme is based on higher order interference between "quantum"
down-converted light and "classical" coherent light. However, this requires
optimizing the amplitude ratio of classical to quantum light thereby limiting
the overall count rate for the interferometric super-resolution signal. We
propose using coherent-beam-stimulated non-collinear down converted light as
input to the interferometer. Our scheme is based on stimulation of
non-collinear parametric down conversion by two-mode coherent light. We have
somehow a better flexibility of choosing the amplitude ratio in generating NOON
states. This enables super-resolution intensity exceeding the previous scheme
by many orders of magnitude. Therefore we hope to improve the magnitude of
N-fold super-resolution in quantum interferometry for arbitrary N by using
bright light sources. We give some results for N=4 and 5.Comment: 8 pages, 3 figure
Heisenberg limited Sagnac interferometry
We show how the entangled photons produced in parametric down conversion can
be used to improve the sensitivity of a Sagnac interferometer. Two-photon and
four-photon coincidences increases the sensitivity by a factor of two and four
respectively. Our results apply to sources with arbitrary pumping and squeezing
parameters.Comment: 11 pages, 5 figure
Quantum interferometry using coherent beam stimulated parametric down-conversion
We show how stimulated parametric processes can be employed in experiments on
beyond the diffraction limit to overcome the problem of low visibility obtained
by using spontaneous down conversion operating in the high gain regime. We
further show enhancement of the count rate by several orders when stimulated
parametric processes are used. Both the two photon counts and the visibility
can be controlled by the phase of the stimulating coherent beam.Comment: 7 pages, 4 figure
Quantum imaging and sensing with entangled photons
This dissertation contains new theoretical work on how to utilize the entangled photons produced in a parametric down conversion to improve resolution and sensitivity in quantum interferometry, magnetometry and lithography. Chapter 1 introduces some basics of quantum imaging and sensing systems and gives an outline of the thesis. Chapter 2 deals with the use of entangled photons in Sagnac interferometry. We introduce the Sagnac ring interferometer and analyze the Sagnac phase shift with classical and quantum inputs of light. We compare the results obtained from entangled photon pairs input with classical and single-photon inputs. We show how the photon-photon correlation measurements increase the resolution and the sensitivity in the phase shift. In chapter three, we present an analysis of how parametric down-converted photons could be utilized in getting better spectroscopic information about a medium which has magnetic field induced anisotropy. We demonstrate how the improvement in magneto-optical rotation (MOR) of light could be realized by employing two different schemes with collinear and noncollinear down-conversion geometries compared to the use of coherent light. We calculate the resolution that can be achieved in the MOR's both by the use of coherent light and down-converted light. We discuss the possibility that the Heisenberg limit could be reached in magnetometry by the use of down-converted light. In chapter 4, we propose a new idea of using coherent beam stimulated parametric processes along with spontaneous ones to produce resolution improvement in two-photon interferometry. The stimulated processes enhance the count rate by several orders of magnitude while at the same time maintaining high visibility at large gains of the parametric process. We further find that the phases of coherent fields can also be used as tuning knobs to control the visibility of the pattern. We use coherent beams at the signal and idler frequencies as the seed light for the down-conversion process. In chapter 5, we analyze the minimum phase uncertainty of the phase measurement in a Mach-Zehnder interferometer using stimulated parametric down-conversion. We calculate the phase sensitivities for different measurement schemes. We conclude the thesis in chapter 6 and give an outlook for future work
Correction: Kolkiran, A.; Agarwal, G.S. Amplitude Noise Reduction in a Nano-Mechanical Oscillator. Math. Comput. Appl. 2011, 16(1), 290β300
The authors would like to remove Girish S. Agarwal from the author list of the paper [1]. Aziz Kolkiran will therefore serve as the single author.[...