Abstract: We holographically measure entangled tangles of phase singularity lines in light genera... more Abstract: We holographically measure entangled tangles of phase singularity lines in light generated via spontaneous parametric down-conversion. This type of entanglement is interesting because it is between topological features that extend over finite, macroscopic, isolated volumes. ...
... 5. Ren and colleagues [36] have used a similar scheme to produce hyper-entangled (entangled i... more ... 5. Ren and colleagues [36] have used a similar scheme to produce hyper-entangled (entangled in OAM, polarization and energy-time) photons. Again these states have three OAM basis states. Thus, the higher-alphabet protocols are experi-mentally realizable now. ...
ABSTRACT We demonstrate an atom trap geometry for ^{87}Rb which is capable of producing ultrahigh... more ABSTRACT We demonstrate an atom trap geometry for ^{87}Rb which is capable of producing ultrahigh atom densities. Reradiation forces, which usually limit high densities, can be avoided in dark spontaneous-force optical traps (dark SPOTs) by sheltering atoms from intense trapping light. Here we demonstrate a dynamic implementation of a dark SPOT, resulting in an increase in atom density by almost two orders of magnitude up to 1.3×10^{12} cm^{−3}. Holographic control of the trapping beams and dynamic switching between magneto-optical trap (MOT) and dark SPOT configuration allows us to optimize the trapping geometry. We have identified the ideal size of the dark core to be six times larger than the MOT. Our method also avoids unwanted heating so that we reach a record phase-space density for a MOT.
Proceedings of CAOL'2003. 1st International Conference on Advanced Optoelectronics and Lasers. Jontly with 1st Workshop on Precision Oscillations in Electronics and Optics (IEEE Cat. No.03EX715)
We discuss several techniques for measuring the topological charge, m, of optical vortices by uti... more We discuss several techniques for measuring the topological charge, m, of optical vortices by utilizing their m-fold rotational symmetry. Such a measurement also amounts to a measurement of the orbital angular momentum (OAM) per photon in units of hbar. The first technique involves the rotational Doppler shift, which was recently suggested as a way to measure the OAM of light beams for optical-communications purposes. The second technique involves interfering an optical vortex with the same vortex, but rotated about the vortex axis by a certain angle. This results in constructive interference for some m values, and destructive interference for other m values. This technique can, in principle, be used to measure the OAM of individual photons. The third technique uses an optical ring resonator that rotates the beam during each round trip. Such a resonator can be tuned to be resonant only for optical vortices with a given values of m. We have used such a resonator to demonstrate an angular form of the uncertainty principle.
Proceedings of SPIE - The International Society for Optical Engineering, 2007
abstract In the 1970s, Jones demonstrated a photon drag by showing that the translation of a wind... more abstract In the 1970s, Jones demonstrated a photon drag by showing that the translation of a window caused a slight displacement of a transmitted light beam. Similarly he showed that a spinning medium slightly rotated the polarization state. Rather than translating the medium, the speed of which is limited by mechanical considerations, we translate the image and measure its lateral delay with respect to a similar image that has not passed through the window. The equivalence, or lack of it, of the two frames is subtle and great care needs to ...
Abstract: We holographically measure entangled tangles of phase singularity lines in light genera... more Abstract: We holographically measure entangled tangles of phase singularity lines in light generated via spontaneous parametric down-conversion. This type of entanglement is interesting because it is between topological features that extend over finite, macroscopic, isolated volumes. ...
... 5. Ren and colleagues [36] have used a similar scheme to produce hyper-entangled (entangled i... more ... 5. Ren and colleagues [36] have used a similar scheme to produce hyper-entangled (entangled in OAM, polarization and energy-time) photons. Again these states have three OAM basis states. Thus, the higher-alphabet protocols are experi-mentally realizable now. ...
ABSTRACT We demonstrate an atom trap geometry for ^{87}Rb which is capable of producing ultrahigh... more ABSTRACT We demonstrate an atom trap geometry for ^{87}Rb which is capable of producing ultrahigh atom densities. Reradiation forces, which usually limit high densities, can be avoided in dark spontaneous-force optical traps (dark SPOTs) by sheltering atoms from intense trapping light. Here we demonstrate a dynamic implementation of a dark SPOT, resulting in an increase in atom density by almost two orders of magnitude up to 1.3×10^{12} cm^{−3}. Holographic control of the trapping beams and dynamic switching between magneto-optical trap (MOT) and dark SPOT configuration allows us to optimize the trapping geometry. We have identified the ideal size of the dark core to be six times larger than the MOT. Our method also avoids unwanted heating so that we reach a record phase-space density for a MOT.
Proceedings of CAOL'2003. 1st International Conference on Advanced Optoelectronics and Lasers. Jontly with 1st Workshop on Precision Oscillations in Electronics and Optics (IEEE Cat. No.03EX715)
We discuss several techniques for measuring the topological charge, m, of optical vortices by uti... more We discuss several techniques for measuring the topological charge, m, of optical vortices by utilizing their m-fold rotational symmetry. Such a measurement also amounts to a measurement of the orbital angular momentum (OAM) per photon in units of hbar. The first technique involves the rotational Doppler shift, which was recently suggested as a way to measure the OAM of light beams for optical-communications purposes. The second technique involves interfering an optical vortex with the same vortex, but rotated about the vortex axis by a certain angle. This results in constructive interference for some m values, and destructive interference for other m values. This technique can, in principle, be used to measure the OAM of individual photons. The third technique uses an optical ring resonator that rotates the beam during each round trip. Such a resonator can be tuned to be resonant only for optical vortices with a given values of m. We have used such a resonator to demonstrate an angular form of the uncertainty principle.
Proceedings of SPIE - The International Society for Optical Engineering, 2007
abstract In the 1970s, Jones demonstrated a photon drag by showing that the translation of a wind... more abstract In the 1970s, Jones demonstrated a photon drag by showing that the translation of a window caused a slight displacement of a transmitted light beam. Similarly he showed that a spinning medium slightly rotated the polarization state. Rather than translating the medium, the speed of which is limited by mechanical considerations, we translate the image and measure its lateral delay with respect to a similar image that has not passed through the window. The equivalence, or lack of it, of the two frames is subtle and great care needs to ...
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Papers by S. Franke-arnold