Abstract
Full text: In this talk, we present a new tunable atom laser design providing coherent atom beams that span a velocities from 10 cm/s to 10 m/s. The upper limit is three orders of magnitude faster than attainable with conventional atom lasers. As we will discuss, fast coherent atoms are easier to detect than slow ones, and this new design is an important step along the path to making dynamic measurements on atom laser beams. We discuss and analyse a series of new, interferometric, dynamic detectors that can be used to measure the noise on atom laser beams. We also discuss and analyse schemes to feedback to the condensate to stabilise and optimise the beam properties. The non-destructive detection of Bose Einstein condensates (BECs) places stringent limits on the measuring system. Spontaneously scattered photons heat the atoms and destroy the condensate. The solution to this problem has been to frequency shift the lasers off resonance and use the phase shift of a far detuned light field to non-destructively image the BEC. This has been employed in techniques such as far-detuned phase contrast imaging. The detector that has been employed, a CCD camera, is slow and is not suited to dynamic,
More>>
Citation Formats
Lye, J E, Robins, N, Fletcher, C S, and Close, J D.
Dynamic detection of a tunable atom laser.
Australia: N. p.,
2002.
Web.
Lye, J E, Robins, N, Fletcher, C S, & Close, J D.
Dynamic detection of a tunable atom laser.
Australia.
Lye, J E, Robins, N, Fletcher, C S, and Close, J D.
2002.
"Dynamic detection of a tunable atom laser."
Australia.
@misc{etde_20619804,
title = {Dynamic detection of a tunable atom laser}
author = {Lye, J E, Robins, N, Fletcher, C S, and Close, J D}
abstractNote = {Full text: In this talk, we present a new tunable atom laser design providing coherent atom beams that span a velocities from 10 cm/s to 10 m/s. The upper limit is three orders of magnitude faster than attainable with conventional atom lasers. As we will discuss, fast coherent atoms are easier to detect than slow ones, and this new design is an important step along the path to making dynamic measurements on atom laser beams. We discuss and analyse a series of new, interferometric, dynamic detectors that can be used to measure the noise on atom laser beams. We also discuss and analyse schemes to feedback to the condensate to stabilise and optimise the beam properties. The non-destructive detection of Bose Einstein condensates (BECs) places stringent limits on the measuring system. Spontaneously scattered photons heat the atoms and destroy the condensate. The solution to this problem has been to frequency shift the lasers off resonance and use the phase shift of a far detuned light field to non-destructively image the BEC. This has been employed in techniques such as far-detuned phase contrast imaging. The detector that has been employed, a CCD camera, is slow and is not suited to dynamic, on-line, measurements. The development of a dynamic measuring system is necessary if we are to obtained detailed information on the noise properties of an atom laser beam, and if we are to use the signal to feedback to the condensate to stabilise the beam. For atom laser beams, there is no non-destructive criterion. This can readily be seen by analogy with the detection of photons from an optical laser beam. Nothing could be more destructive to an optical beam than a photodiode, photomultiplier, or CCD camera. The photons are destroyed and an electron is excited to a new state and recorded. Importantly, the arrival of a photon triggers a predictable response from the detector that can be easily interpreted. A photodetector can be characterised by numbers such as sensitivity, bandwidth, spectral response, dark count, and quantum efficiency, so to can a detector for atoms. Unfortunately, for neutral, ground state, atom lasers, we have no such solid state detectors and we must transform the arrival event of an atom in the detection region into a light signal that can be picked up by a photodetector. That entire process, atom to light to electron, should be viewed together as the detector. In our designs, the bandwidth of the detector is determined by the time of flight of the atom across the detection region. One of the major design criteria that we must satisfy is to maximise the sensitivity of the detector subject to the constraint that the dynamics of the atom crossing the detector is negligibly affected by the detector itself. We discuss and compare several detector designs in this talk.}
place = {Australia}
year = {2002}
month = {Jul}
}
title = {Dynamic detection of a tunable atom laser}
author = {Lye, J E, Robins, N, Fletcher, C S, and Close, J D}
abstractNote = {Full text: In this talk, we present a new tunable atom laser design providing coherent atom beams that span a velocities from 10 cm/s to 10 m/s. The upper limit is three orders of magnitude faster than attainable with conventional atom lasers. As we will discuss, fast coherent atoms are easier to detect than slow ones, and this new design is an important step along the path to making dynamic measurements on atom laser beams. We discuss and analyse a series of new, interferometric, dynamic detectors that can be used to measure the noise on atom laser beams. We also discuss and analyse schemes to feedback to the condensate to stabilise and optimise the beam properties. The non-destructive detection of Bose Einstein condensates (BECs) places stringent limits on the measuring system. Spontaneously scattered photons heat the atoms and destroy the condensate. The solution to this problem has been to frequency shift the lasers off resonance and use the phase shift of a far detuned light field to non-destructively image the BEC. This has been employed in techniques such as far-detuned phase contrast imaging. The detector that has been employed, a CCD camera, is slow and is not suited to dynamic, on-line, measurements. The development of a dynamic measuring system is necessary if we are to obtained detailed information on the noise properties of an atom laser beam, and if we are to use the signal to feedback to the condensate to stabilise the beam. For atom laser beams, there is no non-destructive criterion. This can readily be seen by analogy with the detection of photons from an optical laser beam. Nothing could be more destructive to an optical beam than a photodiode, photomultiplier, or CCD camera. The photons are destroyed and an electron is excited to a new state and recorded. Importantly, the arrival of a photon triggers a predictable response from the detector that can be easily interpreted. A photodetector can be characterised by numbers such as sensitivity, bandwidth, spectral response, dark count, and quantum efficiency, so to can a detector for atoms. Unfortunately, for neutral, ground state, atom lasers, we have no such solid state detectors and we must transform the arrival event of an atom in the detection region into a light signal that can be picked up by a photodetector. That entire process, atom to light to electron, should be viewed together as the detector. In our designs, the bandwidth of the detector is determined by the time of flight of the atom across the detection region. One of the major design criteria that we must satisfy is to maximise the sensitivity of the detector subject to the constraint that the dynamics of the atom crossing the detector is negligibly affected by the detector itself. We discuss and compare several detector designs in this talk.}
place = {Australia}
year = {2002}
month = {Jul}
}