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Slow light

About: Slow light is a(n) research topic. Over the lifetime, 4318 publication(s) have been published within this topic receiving 87534 citation(s).

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Open accessJournal ArticleDOI: 10.1038/17561
18 Feb 1999-Nature
Abstract: Techniques that use quantum interference effects are being actively investigated to manipulate the optical properties of quantum systems1. One such example is electromagnetically induced transparency, a quantum effect that permits the propagation of light pulses through an otherwise opaque medium2,3,4,5. Here we report an experimental demonstration of electromagnetically induced transparency in an ultracold gas of sodium atoms, in which the optical pulses propagate at twenty million times slower than the speed of light in a vacuum. The gas is cooled to nanokelvin temperatures by laser and evaporative cooling6,7,8,9,10. The quantum interference controlling the optical properties of the medium is set up by a ‘coupling’ laser beam propagating at a right angle to the pulsed ‘probe’ beam. At nanokelvin temperatures, the variation of refractive index with probe frequency can be made very steep. In conjunction with the high atomic density, this results in the exceptionally low light speeds observed. By cooling the cloud below the transition temperature for Bose–Einstein condensation11,12,13 (causing a macroscopic population of alkali atoms in the quantum ground state of the confining potential), we observe even lower pulse propagation velocities (17?m?s−1) owing to the increased atom density. We report an inferred nonlinear refractive index of 0.18?cm2?W−1 and find that the system shows exceptionally large optical nonlinearities, which are of potential fundamental and technological interest for quantum optics.

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  • Figure 2 MOC image showing blanketing material ®lling several craters that are 200±400 m in diameter. Image scale, 4.1 by 7.3m per pixel; 3.68 S, 340.58 W. The crater rims are moderately well preserved and visible, indicating that aeolian material has not simply been draped over the topography but has preferentially ®lled the lowest areas. The average depth of fresh 200-m craters is probably ,20 m. Rim heights above surroundings are typically much less than crater depths; thus the ®ll inside these craters is probably deeper than in much of the intervening plains.
    Figure 2 MOC image showing blanketing material ®lling several craters that are 200±400 m in diameter. Image scale, 4.1 by 7.3m per pixel; 3.68 S, 340.58 W. The crater rims are moderately well preserved and visible, indicating that aeolian material has not simply been draped over the topography but has preferentially ®lled the lowest areas. The average depth of fresh 200-m craters is probably ,20 m. Rim heights above surroundings are typically much less than crater depths; thus the ®ll inside these craters is probably deeper than in much of the intervening plains.
  • Figure 1 Experimental set-up. A `coupling' laser beam propagates along the x axis with its linear polarization along the 11-G bias ®eld in the z direction. The `probe' laser pulse propagates along the z axis and is left-circularly polarized. With a ¯ipper mirror in front of the camera CCD 1, we direct this probe beam either to the camera or to the photomultiplier (PMT). For pulse delay measurements, we place apinhole in an external imageplane of the imaging optics and select a small area, 15 mm in diameter, of the probe beam centred on the atom clouds (as indicated by the dashed circle in inset (i)). The pulse delays are measured with the PMT. The imaging beam propagating along the y axis is used to image atom clouds onto camera CCD 2 to ®nd the length of the clouds along the pulse propagation direction (z axis) for determination of light speeds. Inset (ii) shows atoms cooled to 450 nK which is 15nK above Tc. (Note that this imaging beam is never applied at the same time as the probe pulse and coupling laser). The position of a cloud and its diameter in the two transverse directions, x and y, are found with CCD 1. Inset (i) shows an image of a condensate.
    Figure 1 Experimental set-up. A `coupling' laser beam propagates along the x axis with its linear polarization along the 11-G bias ®eld in the z direction. The `probe' laser pulse propagates along the z axis and is left-circularly polarized. With a ¯ipper mirror in front of the camera CCD 1, we direct this probe beam either to the camera or to the photomultiplier (PMT). For pulse delay measurements, we place apinhole in an external imageplane of the imaging optics and select a small area, 15 mm in diameter, of the probe beam centred on the atom clouds (as indicated by the dashed circle in inset (i)). The pulse delays are measured with the PMT. The imaging beam propagating along the y axis is used to image atom clouds onto camera CCD 2 to ®nd the length of the clouds along the pulse propagation direction (z axis) for determination of light speeds. Inset (ii) shows atoms cooled to 450 nK which is 15nK above Tc. (Note that this imaging beam is never applied at the same time as the probe pulse and coupling laser). The position of a cloud and its diameter in the two transverse directions, x and y, are found with CCD 1. Inset (i) shows an image of a condensate.
  • Figure 3 Pulse delay measurement. The front pulse (open circles) is a reference pulse with no atoms in the system. The other pulse (®lled circles) is delayed by 7.05 ms in a 229-mm-long atom cloud (see inset (ii) in Fig.1a). The corresponding light speed is 32.5 ms-1. The curves represent gaussian ®ts to the measured pulses.
    Figure 3 Pulse delay measurement. The front pulse (open circles) is a reference pulse with no atoms in the system. The other pulse (®lled circles) is delayed by 7.05 ms in a 229-mm-long atom cloud (see inset (ii) in Fig.1a). The corresponding light speed is 32.5 ms-1. The curves represent gaussian ®ts to the measured pulses.
  • Figure 2 MOC image showing blanketing material ®lling several craters that are 200±400 m in diameter. Image scale, 4.1 by 7.3m per pixel; 3.68 S, 340.58 W. The crater rims are moderately well preserved and visible, indicating that aeolian material has not simply been draped over the topography but has preferentially ®lled the lowest areas. The average depth of fresh 200-m craters is probably ,20 m. Rim heights above surroundings are typically much less than crater depths; thus the ®ll inside these craters is probably deeper than in much of the intervening plains.
    Figure 2 MOC image showing blanketing material ®lling several craters that are 200±400 m in diameter. Image scale, 4.1 by 7.3m per pixel; 3.68 S, 340.58 W. The crater rims are moderately well preserved and visible, indicating that aeolian material has not simply been draped over the topography but has preferentially ®lled the lowest areas. The average depth of fresh 200-m craters is probably ,20 m. Rim heights above surroundings are typically much less than crater depths; thus the ®ll inside these craters is probably deeper than in much of the intervening plains.
  • Figure 4 Light speed versus atom cloud temperature. The speed decreases with temperature due to the atom density increase. The open circles are for a coupling powerof 52mW cm-2 and the ®lled circles are fora coupling powerof 12mW cm-2. The temperature Tc marks the transition temperature for Bose±Einstein condensation. The decrease in group velocity below Tc is due to a density increase of the atom cloud when the condensate is formed. From imaging measurements we obtain a maximum atom density of 8 3 1013 cm2 3 at a temperature of 200 nK. Here, the dense condensate component constitutes 60% of all atoms, and the total atom density is 16 times larger than the density of a noncondensed cloud at Tc. The light speed measurement at 50 nK is for a cloud with a condensate fraction >90%. The ®nite dephasing rate due to state | 4i does not allow pulse penetration of the most dense clouds. This problem could be overcome by tuning the laser to the Dl line as described in the text.
    Figure 4 Light speed versus atom cloud temperature. The speed decreases with temperature due to the atom density increase. The open circles are for a coupling powerof 52mW cm-2 and the ®lled circles are fora coupling powerof 12mW cm-2. The temperature Tc marks the transition temperature for Bose±Einstein condensation. The decrease in group velocity below Tc is due to a density increase of the atom cloud when the condensate is formed. From imaging measurements we obtain a maximum atom density of 8 3 1013 cm2 3 at a temperature of 200 nK. Here, the dense condensate component constitutes 60% of all atoms, and the total atom density is 16 times larger than the density of a noncondensed cloud at Tc. The light speed measurement at 50 nK is for a cloud with a condensate fraction >90%. The ®nite dephasing rate due to state | 4i does not allow pulse penetration of the most dense clouds. This problem could be overcome by tuning the laser to the Dl line as described in the text.
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Topics: Electromagnetically induced transparency (65%), Quantum optics (60%), Slow light (58%) ...read more

3,254 Citations


Journal ArticleDOI: 10.1103/PHYSREVLETT.101.047401
Shuang Zhang1, Dentcho A. Genov1, Yuan Wang1, Ming Liu1  +1 moreInstitutions (1)
Abstract: A plasmonic "molecule" consisting of a radiative element coupled with a subradiant (dark) element is theoretically investigated. The plasmonic molecule shows electromagnetic response that closely resembles the electromagnetically induced transparency in an atomic system. Because of its subwavelength dimension, this electromagnetically induced transparency-like molecule can be used as a building block to construct a "slow light" plasmonic metamaterial.

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Topics: Electromagnetically induced transparency (62%), Metamaterial (54%), Slow light (54%) ...read more

1,879 Citations


Open accessJournal ArticleDOI: 10.1038/NPHOTON.2008.146
Toshihiko Baba1Institutions (1)
01 Aug 2008-Nature Photonics
Abstract: Slow light with a remarkably low group velocity is a promising solution for buffering and time-domain processing of optical signals. It also offers the possibility for spatial compression of optical energy and the enhancement of linear and nonlinear optical effects. Photonic-crystal devices are especially attractive for generating slow light, as they are compatible with on-chip integration and room-temperature operation, and can offer wide-bandwidth and dispersion-free propagation. Here the background theory, recent experimental demonstrations and progress towards tunable slow-light structures based on photonic-band engineering are reviewed. Practical issues related to real devices and their applications are also discussed. The unique properties of wide-bandwidth and dispersion-free propagation in photonic-crystal devices have made them a good candidate for slow-light generation. This article gives the background theory of slow light, as well as an overview of recent experimental demonstrations based on photonic-band engineering.

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Topics: Slow light (60%), Photonics (54%)

1,620 Citations


Journal ArticleDOI: 10.1038/NMAT2495
Na Liu1, Lutz Langguth1, Thomas Weiss1, Jürgen Kästel2  +3 moreInstitutions (2)
01 Sep 2009-Nature Materials
Abstract: In atomic physics, the coherent coupling of a broad and a narrow resonance leads to quantum interference and provides the general recipe for electromagnetically induced transparency (EIT). A sharp resonance of nearly perfect transmission can arise within a broad absorption profile. These features show remarkable potential for slow light, novel sensors and low-loss metamaterials. In nanophotonics, plasmonic structures enable large field strengths within small mode volumes. Therefore, combining EIT with nanoplasmonics would pave the way towards ultracompact sensors with extremely high sensitivity. Here, we experimentally demonstrate a nanoplasmonic analogue of EIT using a stacked optical metamaterial. A dipole antenna with a large radiatively broadened linewidth is coupled to an underlying quadrupole antenna, of which the narrow linewidth is solely limited by the fundamental non-radiative Drude damping. In accordance with EIT theory, we achieve a very narrow transparency window with high modulation depth owing to nearly complete suppression of radiative losses. Plasmonic nanostructures enable the concentration of large electric fields into small spaces. The classical analogue of electromagnetically induced transparency has now been achieved in such devices, leading to a narrow resonance in their absorption spectrum. This combination of high electric-field concentration and sharp resonance offers a pathway to ultracompact sensors with extremely high sensitivity.

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Topics: Electromagnetically induced transparency (62%), Slow light (53%), Metamaterial (52%) ...read more

1,510 Citations


Journal ArticleDOI: 10.1038/NATURE04210
03 Nov 2005-Nature
Abstract: It is known that light can be slowed down in dispersive materials near resonances. Dramatic reduction of the light group velocity-and even bringing light pulses to a complete halt-has been demonstrated recently in various atomic and solid state systems, where the material absorption is cancelled via quantum optical coherent effects. Exploitation of slow light phenomena has potential for applications ranging from all-optical storage to all-optical switching. Existing schemes, however, are restricted to the narrow frequency range of the material resonance, which limits the operation frequency, maximum data rate and storage capacity. Moreover, the implementation of external lasers, low pressures and/or low temperatures prevents miniaturization and hinders practical applications. Here we experimentally demonstrate an over 300-fold reduction of the group velocity on a silicon chip via an ultra-compact photonic integrated circuit using low-loss silicon photonic crystal waveguides that can support an optical mode with a submicrometre cross-section. In addition, we show fast (approximately 100 ns) and efficient (2 mW electric power) active control of the group velocity by localized heating of the photonic crystal waveguide with an integrated micro-heater.

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Topics: Photonic integrated circuit (64%), Slow light (64%), Photonic crystal (60%) ...read more

1,246 Citations


Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20222
2021146
2020165
2019161
2018202
2017221

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Topic's top 5 most impactful authors

Thomas F. Krauss

123 papers, 5.6K citations

Toshihiko Baba

108 papers, 3.4K citations

Liam O'Faolain

80 papers, 3.5K citations

Robert W. Boyd

79 papers, 4.6K citations

Benjamin J. Eggleton

54 papers, 1.4K citations

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