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Frontiers in Optics

Slow Darkness and Rotary Photon Drag

Emma Wisniewski‐Barker, Graham M. Gibson, Sonja Franke‐Arnold, Robert W. Boyd, Miles J. Padgett

Published Jan 1, 2012• 0 citations
Publisher

Abstract

We observe rotary photon drag significantly enhanced in magnitude by slow-light methods. Specifically, we observe the angular displacement of an image-carrying beam as it passes trough a spinning self-pumped ruby rod. We observe that both the dark and bright regions of the beam are dragged by similar amounts, showing that the slow-light effect extends to slow-darkness too.

DOI
10.1364/fio.2012.fth1e.2

Related papers

Evidence of slow-light effects from rotary drag of structured beams

Emma Wisniewski‐Barker, Graham M. Gibson, Sonja Franke‐Arnold +3 more

Self-pumped slow light, typically observed within laser gain media, is created by an intense pump field. By observing the rotation of a structured laser beam upon transmission through a spinning ruby window, we show that the slowing effect applies equally to both the dark and bright regions of the incident beam. This result is incompatible with slow-light models based on simple pulse-reshaping arising from optical bleaching. Instead, the slow-light effect arises from the long upper-state lifetime of the ruby and a saturation of the absorption, from which the Kramers–Kronig relation gives a highly dispersive phase index and a correspondingly high group index.

New Journal of Physics•Aug 8, 2013•16 citations

Rotary Photon Drag Enhanced by a Slow-Light Medium

Sonja Franke‐Arnold, Graham M. Gibson, Robert W. Boyd +1 more

Transmission through a spinning window slightly rotates the polarization of the light, typically by a microradian. It has been predicted that the same mechanism should also rotate an image. Because this rotary photon drag has a contribution that is inversely proportional to the group velocity, the image rotation is expected to increase in a slow-light medium. Using a ruby window under conditions for coherent population oscillations, we induced an effective group index of about 1 million. The resulting rotation angle was large enough to be observed by the eye. This result shows that rotary photon drag applies to images as well as polarization. The possibility of switching between different rotation states may offer new opportunities for controlled image coding.

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Reply to Comment on ‘Evidence of slow-light effects from rotary drag of structured beams’

Emma Wisniewski‐Barker, Graham M. Gibson, Sonja Franke‐Arnold +3 more

The phenomenon of self-pumped slow light, where a single beam appears to be slowed by a solid-state media, is both subtle and controversial. Here, we reply to a comment on our recent work, which uses an observation of enhanced photon drag to distinguish between group delay and pulse reshaping.

New Journal of Physics•Mar 28, 2014•3 citations

Comment on "Rotary Photon Drag Enhanced by a Slow-Light Medium [1]"

Adrian C. Selden

The observations reported by Franke-Arnold et al (SCIENCE Reports, 1 July 2011 p. 65) do not provide evidence of slow light enhanced rotary photon drag as claimed, but arise from well-known saturable absorption phenomena consistent with the use of a spectrally broad light source, as described in their theoretical analysis (supporting online material)

arXiv:1201.3226•Jan 16, 2012•0 citations

Slow light in ruby:a study in spatial and temporal domains

Emma Wisniewski‐Barker

Slow light is the study of the dramatic change in the velocity of light as it travels through certain media. This thesis focuses on slowing caused by transmitting light through a ruby crystal. When ruby experiences spatial or temporal modulation from a laser beam, the velocity of the light is greatly changed from its speed in a vacuum. The underlying mechanism for slow light in ruby is not fully understood and is, therefore, the subject of much debate. In this thesis, I examine many experimental parameters and their effects on slow light in ruby. First, I investigate the delay of images with both bright and dark regions through a spatial modulation of the ruby. I then turn to a temporal modulation of the ruby to answer the question of whether light can be delayed beyond the input pulse, the answer to which has the potential to differentiate between two proposed models for the mechanism that causes slow light in ruby. I return to the spatial domain to study the effect of spatial intensity distribution on the slow-light effect in ruby. I show that beams carrying orbital angular momentum rotate by an amount determined by the spatial feature of the beam profile. I present experimental evidence supporting a complicated mechanism of slow light in ruby, which informs the ongoing debate on the cause of slow light in ruby and provides direction for applications dependent upon the preservation of complex patterns in slow-light media.

•Jan 1, 2015•0 citations

Coherent manipulation of rotary photon drag by implication of Milnor polynomial

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Abstract Subluminal and superluminal propagation of light, and normal and anomalous rotary photon drag are reported in this manuscript using control fields of the Milnor polynomial. A crater-type absorption spectrum is reported, having a central peak at the origin with a variation of positions. The normal and anomalous dispersion are associated with the low and high absorption regions. The group index varies in the range of − 1 × 10 7 ⩽ n g ⩽ 1 × 10 7 . This corresponds to a group velocity of v g = c / n g varying in the range of − 30 m s − 1 ⩽ v g ⩽ 30 m s − 1 . The maximum positive and negative delay times are measured to ± 0.002 s . It is reported that slow light propagation generates normal photon drag and fast light propagation generates anomalous rotary photon drag in a spinning medium. The rotary photon drag varies in the range of − 0.005 rad ⩽ θ d ⩽ 0.005 rad , where both normal and anomalous drag is also observed. The modified results will be useful in optical and biomedical sensors, and imaging and telecommunication technologies.

Journal of Optics•Mar 19, 2025•9 citations
We observe rotary photon drag significantly enhanced in magnitude by slow-light methods. Specifically, we observe the angular displacement of an image-carrying beam as it passes trough a spinning self-pumped ruby rod. We observe that both the dark and bright regions of the beam are dragged by similar amounts, showing that the slow-light effect extends to slow-darkness too.
Self-pumped slow light, typically observed within laser gain media, is created by an intense pump field. By observing the rotation of a structured laser beam upon transmission through a spinning ruby window, we show that the slowing effect applies equally to both the dark and bright regions of the incident beam. This result is incompatible with slow-light models based on simple pulse-reshaping arising from optical bleaching. Instead, the slow-light effect arises from the long upper-state lifetime of the ruby and a saturation of the absorption, from which the Kramers–Kronig relation gives a highly dispersive phase index and a correspondingly high group index.
Transmission through a spinning window slightly rotates the polarization of the light, typically by a microradian. It has been predicted that the same mechanism should also rotate an image. Because this rotary photon drag has a contribution that is inversely proportional to the group velocity, the image rotation is expected to increase in a slow-light medium. Using a ruby window under conditions for coherent population oscillations, we induced an effective group index of about 1 million. The resulting rotation angle was large enough to be observed by the eye. This result shows that rotary photon drag applies to images as well as polarization. The possibility of switching between different rotation states may offer new opportunities for controlled image coding.
Slow light is the study of the dramatic change in the velocity of light as it travels through certain media. This thesis focuses on slowing caused by transmitting light through a ruby crystal. When ruby experiences spatial or temporal modulation from a laser beam, the velocity of the light is greatly changed from its speed in a vacuum. The underlying mechanism for slow light in ruby is not fully understood and is, therefore, the subject of much debate. In this thesis, I examine many experimental parameters and their effects on slow light in ruby. First, I investigate the delay of images with both bright and dark regions through a spatial modulation of the ruby. I then turn to a temporal modulation of the ruby to answer the question of whether light can be delayed beyond the input pulse, the answer to which has the potential to differentiate between two proposed models for the mechanism that causes slow light in ruby. I return to the spatial domain to study the effect of spatial intensity distribution on the slow-light effect in ruby. I show that beams carrying orbital angular momentum rotate by an amount determined by the spatial feature of the beam profile. I present experimental evidence supporting a complicated mechanism of slow light in ruby, which informs the ongoing debate on the cause of slow light in ruby and provides direction for applications dependent upon the preservation of complex patterns in slow-light media.
Abstract Subluminal and superluminal propagation of light, and normal and anomalous rotary photon drag are reported in this manuscript using control fields of the Milnor polynomial. A crater-type absorption spectrum is reported, having a central peak at the origin with a variation of positions. The normal and anomalous dispersion are associated with the low and high absorption regions. The group index varies in the range of − 1 × 10 7 ⩽ n g ⩽ 1 × 10 7 . This corresponds to a group velocity of v g = c / n g varying in the range of − 30 m s − 1 ⩽ v g ⩽ 30 m s − 1 . The maximum positive and negative delay times are measured to ± 0.002 s . It is reported that slow light propagation generates normal photon drag and fast light propagation generates anomalous rotary photon drag in a spinning medium. The rotary photon drag varies in the range of − 0.005 rad ⩽ θ d ⩽ 0.005 rad , where both normal and anomalous drag is also observed. The modified results will be useful in optical and biomedical sensors, and imaging and telecommunication technologies.