The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Marlan O Scully - One of the best experts on this subject based on the ideXlab platform.

  • Beam Focusing and reduction of quantum uncertainty in width at the few photon level via multi spatial mode squeezing
    Physical Review Letters, 2019
    Co-Authors: Lida Zhang, G S Agarwal, Marlan O Scully
    Abstract:

    We show for the first time that it is possible to realize laser Beam Focusing at the few-photon level in the four-wave-mixing process, and at the same time reduce the quantum uncertainty in width. The reduction in quantum uncertainty results directly from the strong suppression of local intensity fluctuations. This surprising effect of simultaneous Focusing and reduction of width uncertainty is enabled by multi-spatial-mode (MSM) squeezing, and is not possible via any classical optical approach or single-spatial-mode squeezing. Our results open promising possibilities for quantum-enhanced imaging and metrology; as an example, the limit on the measurement of very small Beam displacement can be enhanced within feasible experimental parameters because of Beam Focusing and the noiseless amplification in the MSM squeezing process.

Laura N Kloepper - One of the best experts on this subject based on the ideXlab platform.

  • support for the Beam Focusing hypothesis in the false killer whale
    The Journal of Experimental Biology, 2015
    Co-Authors: Laura N Kloepper, John R Buck, Adam B Smith, Alexander Ya Supin, Jason E Gaudette, Paul E Nachtigall
    Abstract:

    The odontocete sound production system is complex and composed of tissues, air sacs, and a fatty melon. Previous studies suggested that the emitted sonar Beam might be actively focused, narrowing depending on target distance. In this study, we further tested this Beam Focusing hypothesis in a false killer whale. Using three linear arrays of hydrophones, we recorded the same emitted click at 2, 4 and 7 m distance and calculated the Beamwidth, intensity, center frequency, and bandwidth as recorded on each array at every distance. If the whale did not focus her Beam, acoustics predicts the intensity would decay with range as a function of spherical spreading and the angular Beamwidth would remain constant. On the contrary, our results show that as the distance from the whale to the array increases, the Beamwidth is narrower and the received click intensity is higher than that predicted by a spherical spreading function. Each of these measurements is consistent with the animal Focusing its Beam on a target at a given range. These results support the hypothesis that the false killer whale is "Focusing" its sonar Beam, producing a narrower and more intense signal than that predicted by spherical spreading.

  • testing the Beam Focusing hypothesis in a false killer whale using hydrophone arrays
    Journal of the Acoustical Society of America, 2014
    Co-Authors: Laura N Kloepper, Paul E Nachtigall, John R Buck, Adam B Smith, Jason E Gaudette
    Abstract:

    The odontocete sound production system is complex and composed of tissues, air sacs, and a fatty melon. Previous studies suggested that the emitted sonar Beam might be actively focused, narrowing depending on target distance. In this study, we further tested this Beam Focusing hypothesis in a false killer whale (Pseudorca crassidens) in a laboratory setting. Using three linear arrays, we recorded the same emitted click at 2, 4, and 7 m distance while the animal performed a target detection task with the target distance varying between 2, 4, and 7 m. For each click, we calculated the Beamwidth, intensity, center frequency, and bandwidth as recorded on each array. As the distance from the whale to the array increased, the received click intensity was higher than predicted by spreading loss. Moreover, the Beamwidth varied with range as predicted by the Focusing model and contrary to a piston model or spherical spreading. These results support the hypothesis that the false killer whale adaptively focuses its ...

  • active echolocation Beam Focusing in the false killer whale pseudorca crassidens
    The Journal of Experimental Biology, 2012
    Co-Authors: Laura N Kloepper, Megan J Donahue, Paul E Nachtigall, Marlee Breese
    Abstract:

    SUMMARY The odontocete sound production system is highly complex and produces intense, directional signals that are thought to be focused by the melon and the air sacs. Because odontocete echolocation signals are variable and the emitted click frequency greatly affects the echolocation Beam shape, investigations of Beam Focusing must account for frequency-related Beam changes. In this study we tested whether the echolocation Beam of a false killer whale changed depending on target difficulty and distance while also accounting for frequency-related changes in the echolocation Beam. The data indicate that the false killer whale changes its Beam size according to target distance and difficulty, which may be a strategy of maximizing the energy of the target echo. We propose that the animal is using a strategy of changing the focal region according to target distance and that this strategy is under active control.

  • echolocation Beam shape and Focusing in the false killer whale pseudorca crassidens
    Journal of the Acoustical Society of America, 2012
    Co-Authors: Laura N Kloepper, Paul E Nachtigall, Marlee Breese
    Abstract:

    Odontocete echolocation signals are thought to be focused by the melon and air sacs, although active Focusing has yet to be demonstrated empirically. Because odontocete echolocation signals are variable and the emitted click frequency greatly affects the echolocation Beam shape, investigations of Beam Focusing must account for frequency-related Beam changes. Using a fine scale hydrophone array, we measured the shape of the echolocation Beam and tested whether the echolocation Beam of a false killer whale changed depending on target difficulty and distance while also accounting for frequency-related changes in the echolocation Beam. The false killer whale produced a single-lobed echolocation Beam that changed in size depending on target distance and difficulty which may be a strategy of actively controlling the emitted Beam to maximize energy of the target echo.

Paul E Nachtigall - One of the best experts on this subject based on the ideXlab platform.

  • support for the Beam Focusing hypothesis in the false killer whale
    The Journal of Experimental Biology, 2015
    Co-Authors: Laura N Kloepper, John R Buck, Adam B Smith, Alexander Ya Supin, Jason E Gaudette, Paul E Nachtigall
    Abstract:

    The odontocete sound production system is complex and composed of tissues, air sacs, and a fatty melon. Previous studies suggested that the emitted sonar Beam might be actively focused, narrowing depending on target distance. In this study, we further tested this Beam Focusing hypothesis in a false killer whale. Using three linear arrays of hydrophones, we recorded the same emitted click at 2, 4 and 7 m distance and calculated the Beamwidth, intensity, center frequency, and bandwidth as recorded on each array at every distance. If the whale did not focus her Beam, acoustics predicts the intensity would decay with range as a function of spherical spreading and the angular Beamwidth would remain constant. On the contrary, our results show that as the distance from the whale to the array increases, the Beamwidth is narrower and the received click intensity is higher than that predicted by a spherical spreading function. Each of these measurements is consistent with the animal Focusing its Beam on a target at a given range. These results support the hypothesis that the false killer whale is "Focusing" its sonar Beam, producing a narrower and more intense signal than that predicted by spherical spreading.

  • testing the Beam Focusing hypothesis in a false killer whale using hydrophone arrays
    Journal of the Acoustical Society of America, 2014
    Co-Authors: Laura N Kloepper, Paul E Nachtigall, John R Buck, Adam B Smith, Jason E Gaudette
    Abstract:

    The odontocete sound production system is complex and composed of tissues, air sacs, and a fatty melon. Previous studies suggested that the emitted sonar Beam might be actively focused, narrowing depending on target distance. In this study, we further tested this Beam Focusing hypothesis in a false killer whale (Pseudorca crassidens) in a laboratory setting. Using three linear arrays, we recorded the same emitted click at 2, 4, and 7 m distance while the animal performed a target detection task with the target distance varying between 2, 4, and 7 m. For each click, we calculated the Beamwidth, intensity, center frequency, and bandwidth as recorded on each array. As the distance from the whale to the array increased, the received click intensity was higher than predicted by spreading loss. Moreover, the Beamwidth varied with range as predicted by the Focusing model and contrary to a piston model or spherical spreading. These results support the hypothesis that the false killer whale adaptively focuses its ...

  • active echolocation Beam Focusing in the false killer whale pseudorca crassidens
    The Journal of Experimental Biology, 2012
    Co-Authors: Laura N Kloepper, Megan J Donahue, Paul E Nachtigall, Marlee Breese
    Abstract:

    SUMMARY The odontocete sound production system is highly complex and produces intense, directional signals that are thought to be focused by the melon and the air sacs. Because odontocete echolocation signals are variable and the emitted click frequency greatly affects the echolocation Beam shape, investigations of Beam Focusing must account for frequency-related Beam changes. In this study we tested whether the echolocation Beam of a false killer whale changed depending on target difficulty and distance while also accounting for frequency-related changes in the echolocation Beam. The data indicate that the false killer whale changes its Beam size according to target distance and difficulty, which may be a strategy of maximizing the energy of the target echo. We propose that the animal is using a strategy of changing the focal region according to target distance and that this strategy is under active control.

  • echolocation Beam shape and Focusing in the false killer whale pseudorca crassidens
    Journal of the Acoustical Society of America, 2012
    Co-Authors: Laura N Kloepper, Paul E Nachtigall, Marlee Breese
    Abstract:

    Odontocete echolocation signals are thought to be focused by the melon and air sacs, although active Focusing has yet to be demonstrated empirically. Because odontocete echolocation signals are variable and the emitted click frequency greatly affects the echolocation Beam shape, investigations of Beam Focusing must account for frequency-related Beam changes. Using a fine scale hydrophone array, we measured the shape of the echolocation Beam and tested whether the echolocation Beam of a false killer whale changed depending on target difficulty and distance while also accounting for frequency-related changes in the echolocation Beam. The false killer whale produced a single-lobed echolocation Beam that changed in size depending on target distance and difficulty which may be a strategy of actively controlling the emitted Beam to maximize energy of the target echo.

Greg T Clement - One of the best experts on this subject based on the ideXlab platform.

  • time reversal transcranial ultrasound Beam Focusing using a k space method
    Physics in Medicine and Biology, 2012
    Co-Authors: Yun Jing, Can F Meral, Greg T Clement
    Abstract:

    This paper proposes the use of a k-space method to obtain the correction for transcranial ultrasound Beam Focusing. Mirroring past approaches, a synthetic point source at the focal point is numerically excited, and propagated through the skull, using acoustic properties acquired from registered computed tomography of the skull being studied. The received data outside the skull contain the correction information and can be phase conjugated (time reversed) and then physically generated to achieve a tight Focusing inside the skull, by assuming quasi-plane transmission where shear waves are not present or their contribution can be neglected. Compared with the conventional finite-difference time-domain method for wave propagation simulation, it will be shown that the k-space method is significantly more accurate even for a relatively coarse spatial resolution, leading to a dramatically reduced computation time. Both numerical simulations and experiments conducted on an ex vivo human skull demonstrate that precise Focusing can be realized using the k-space method with a spatial resolution as low as only 2.56 grid points per wavelength, thus allowing treatment planning computation on the order of minutes.

Marlee Breese - One of the best experts on this subject based on the ideXlab platform.

  • active echolocation Beam Focusing in the false killer whale pseudorca crassidens
    The Journal of Experimental Biology, 2012
    Co-Authors: Laura N Kloepper, Megan J Donahue, Paul E Nachtigall, Marlee Breese
    Abstract:

    SUMMARY The odontocete sound production system is highly complex and produces intense, directional signals that are thought to be focused by the melon and the air sacs. Because odontocete echolocation signals are variable and the emitted click frequency greatly affects the echolocation Beam shape, investigations of Beam Focusing must account for frequency-related Beam changes. In this study we tested whether the echolocation Beam of a false killer whale changed depending on target difficulty and distance while also accounting for frequency-related changes in the echolocation Beam. The data indicate that the false killer whale changes its Beam size according to target distance and difficulty, which may be a strategy of maximizing the energy of the target echo. We propose that the animal is using a strategy of changing the focal region according to target distance and that this strategy is under active control.

  • echolocation Beam shape and Focusing in the false killer whale pseudorca crassidens
    Journal of the Acoustical Society of America, 2012
    Co-Authors: Laura N Kloepper, Paul E Nachtigall, Marlee Breese
    Abstract:

    Odontocete echolocation signals are thought to be focused by the melon and air sacs, although active Focusing has yet to be demonstrated empirically. Because odontocete echolocation signals are variable and the emitted click frequency greatly affects the echolocation Beam shape, investigations of Beam Focusing must account for frequency-related Beam changes. Using a fine scale hydrophone array, we measured the shape of the echolocation Beam and tested whether the echolocation Beam of a false killer whale changed depending on target difficulty and distance while also accounting for frequency-related changes in the echolocation Beam. The false killer whale produced a single-lobed echolocation Beam that changed in size depending on target distance and difficulty which may be a strategy of actively controlling the emitted Beam to maximize energy of the target echo.