19 research outputs found
Quantum diffraction and interference of spatially correlated photon pairs generated by spontaneous parametric down-conversion
We demonstrate one- and two-photon diffraction and interference experiments
utilizing parametric down-converted photon pairs (biphotons) and a transmission
grating. With two-photon detection, the biphoton exhibits a
diffraction-interference pattern equivalent to that of an effective single
particle that is associated with half the wavelength of the constituent
photons. With one-photon detection, however no diffraction-interference pattern
is observed. We show that these phenomena originate from the spatial quantum
correlation between the down-converted photons.Comment: 4 pages, 5 figure
Spectroscopy by frequency entangled photon pairs
Quantum spectroscopy was performed using the frequency-entangled broadband
photon pairs generated by spontaneous parametric down-conversion. An absorptive
sample was placed in front of the idler photon detector, and the frequency of
signal photons was resolved by a diffraction grating. The absorption spectrum
of the sample was measured by counting the coincidences, and the result is in
agreement with the one measured by a conventional spectrophotometer with a
classical light source.Comment: 11 pages, 5 figures, to be published in Phys. Lett.
Creation of maximally entangled photon-number states using optical fiber multiports
We theoretically demonstrate a method for producing the maximally
path-entangled state (1/Sqrt[2]) (|N,0> + exp[iN phi] |0,N>) using
intensity-symmetric multiport beamsplitters, single photon inputs, and either
photon-counting postselection or conditional measurement. The use of
postselection enables successful implementation with non-unit efficiency
detectors. We also demonstrate how to make the same state more conveniently by
replacing one of the single photon inputs by a coherent state.Comment: 4 pages, 1 figure. REVTeX4. Replaced with published versio
Extracting Spatial Information from Noise Measurements of Multi-Spatial-Mode Quantum States
We show that it is possible to use the spatial quantum correlations present
in twin beams to extract information about the shape of a mask in the path of
one of the beams. The scheme, based on noise measurements through homodyne
detection, is useful in the regime where the number of photons is low enough
that direct detection with a photodiode is difficult but high enough that
photon counting is not an option. We find that under some conditions the use of
quantum states of light leads to an enhancement of the sensitivity in the
estimation of the shape of the mask over what can be achieved with a classical
state with equivalent properties (mean photon flux and noise properties). In
addition, we show that the level of enhancement that is obtained is a result of
the quantum correlations and cannot be explained with only classical
correlations
Quantum spiral bandwidth of entangled two-photon states
We put forward the concept of quantum spiral bandwidth of the spatial mode
function of the two-photon entangled state in spontaneous parametric
downconversion. We obtain the bandwidth using the eigenstates of the orbital
angular momentum of the biphoton states, and reveal its dependence with the
length of the down converting crystal and waist of the pump beam. The
connection between the quantum spiral bandwidth and the entropy of entanglement
of the quantum state is discussed.Comment: 10 pages, 3 figure
A biphotons double slit experiment
In this paper we present a double slit experiment where two undistinguishable
photons produced by type I PDC are sent each to a well defined slit. Data about
the diffraction and interference patterns for coincidences are presented and
discussed. An analysis of these data allows a first test of standard quantum
mechanics against de Broglie-Bohm theory
Quantum theory of two-photon interference
In this paper, we study two-photon interference with the approach of photon
quantum theory, with specific attention to the two-photon interference
experiment carried out by Milena D'Angelo et al. (Phys. Rev. Lett 87:013602,
2001). We find the theoretical result is accordance with experiment data.Comment: arXiv admin note: substanital text overlap with arXiv:1011.3593, and
with arXiv:quant-ph/0408001, arXiv:quant-ph/0103035 by other author