The creation of photonic orbital angular momentum in electromagnetic waves propagating through turbulence

Sanchez, Darryl J.; Oesch, Denis W.; Reynolds, Odell R.

doi:10.1051/0004-6361/201219901

Cited by 9 publications

(14 citation statements)

References 36 publications

(60 reference statements)

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“…Table 3 shows the original results of the 2011 SOR observations from Sanchez et al (2013) by star name and observation time. The 2011 conversion efficiencies are provided along with the relative signal strengths as the number of standard deviations above the noise floor, N σ .…”

Section: Poam Estimation Through ηmentioning

confidence: 99%

“…Interestingly, both Silva et al (2011) andHarper (1992) studied HR 1577 for evidence of turbulence. However, they were looking at turbulence in the photospheres of G and K stars whereas Sanchez et al (2013) was looking for TAMA between the Earth and the candidate stars. The original analysis concluded that any POAM signal was below the noise floor of the detector.…”

Section: Hr 1577mentioning

confidence: 99%

“…The purpose of the initial observations and analysis by Sanchez et al (2013) was simply to verify that a POAM signal was present in accordance with the theoretical predictions. The purpose of this work is to reanalyze the data using a more refined technique and come to firmer conclusions about the POAM signal found in the initial observations.…”

Section: Introductionmentioning

confidence: 97%

“…The demonstration that POAM is a natural consequence of the interaction of light and turbulence (Sanchez & Oesch 2011a,b;Oesch et al 2013), provides a mechanism by which POAM may be created in large quantities by astrophysical systems. Sanchez et al (2013) explained this mechanism in the context of astronomical turbulence along with a survey of the POAM signal from five stars using the 3.5 m telescope and natural guide star wavefront sensor (WFS) at the Starfire Optical Range (SOR). The original survey stars: 49 Ceti, HR 1784, HR 1529, HR 1577 and HR 1895, were chosen primarily based on their altitude and brightness at the time of the observations, but two of these candidate stars were chosen because of their known association with a turbulent assemblage of molecules or atoms (TAMA).…”

Section: Introductionmentioning

confidence: 99%

“…Both types of phase gradients were collected in the 2011 observations, however the conversion efficiency was a newly developed metric and therefore the original estimate of the POAM signal in Sanchez et al (2013) relied heavily on establishing a noise floor, η floor , for the instrument. In presenting the first measurements of on-sky POAM signals, a very conservative estimate was used to avoid ambiguity in the measurement.…”

Section: Introductionmentioning

confidence: 99%

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Photonic orbital angular momentum in starlight

Oesch

Sanchez

2014

A&A

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Context. Each attempt by the Atmospheric Simulation and Adaptive-optics Laboratory Testbed (ASALT) research group to detect turbulence-induced photonic orbital angular momentum (POAM) has been successful, spanning laboratory, simulation and field experiments, with the possible exception of the 2011 Starfire Optical Range (SOR) astronomical observations, a search for POAM induced by astronomical sources. Aims. The purposes of this work are to discuss how POAM from astronomical turbulent assemblages of molecules or atoms (TAMA) would appear in observations and then to reanalyze the data from the 2011 SOR observations using a more refined technique as a demonstration of POAM in starlight. Methods. This work uses the method of projections used previously in analysis of terrestrial data. Results. Using the method of projections, the noise floor of the system was reevaluated and is found to be no greater than 1%. Reevaluation of the 2011 SOR observations reveals that a POAM signal is evident in all of the data. Conclusions. POAM signals have been found in every instance of extended propagation through turbulence conducted by the ASALT research group, including the 2011 SOR observations. POAM is an inevitable result of the propagation of optical waves through turbulence.

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Section: Poam Estimation Through ηmentioning

confidence: 99%

Section: Hr 1577mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photonic orbital angular momentum in starlight

Oesch

Sanchez

2014

A&A

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Recent advances in generation of terahertz vortex beams and their applications*

Wang¹,

Song²,

Cai³

et al. 2020

Chinese Phys. B

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Last decade has witnessed a rapid development of the generation of terahertz (THz) vortex beams as well as their wide applications, mainly due to their unique combination characteristics of regular THz radiation and orbital angular momentum (OAM). Here we have reviewed the ways to generate THz vortex beams by two representative scenarios, i.e., THz wavefront modulation via specific devices, and direct excitation of the helicity of THz vortex beams. The former is similar to those wavefront engineering devices in the optical and infrared (IR) domain, but just with suitable THz materials, while the latter is newly-developed in THz regime and some of the physical mechanisms still have not been explained explicitly enough though, which would provide both challenges and opportunities for THz vortex beam generation. As for their applications, thanks to the recent development of THz optics and singular optics, THz vortex beams have potentials to open doors towards a myriad of practice applications in many fields. Besides, some representative potential applications are evaluated such as THz wireless communication, THz super-resolution imaging, manipulating chiral matters, accelerating electron bunches, and detecting astrophysical sources.

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Amplification of OAM radiation by astrophysical masers

Gray

Pisano

Maccalli

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We extend the theory of astrophysical maser propagation through a medium with a Zeemansplit molecular response to the case of a non-uniform magnetic field, and allow a component of the electric field of the radiation in the direction of propagation: a characteristic of radiation with orbital angular momentum. A classical reduction of the governing equations leads to a set of nine differential equations for the evolution of intensity-like parameters for each Fourier component of the radiation. Four of these parameters correspond to the standard Stokes parameters, whilst the other five represent the z-component of the electric field, and its coupling to the conventional components in the x − y-plane. A restricted analytical solution of the governing equations demonstrates a non-trivial coupling of the Stokes parameters to those representing orbital angular momentum: the z-component of the electric field can grow from a background in which only Stokes-I is non-zero. A numerical solution of the governing equations reveals radiation patterns with a radial and angular structure for the case of an ideal quadrupole magnetic field perpendicular to the propagation direction. In this ideal case generation of radiation orbital angular momentum, like polarization, can approach 100 per cent.

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The creation of photonic orbital angular momentum in electromagnetic waves propagating through turbulence

Cited by 9 publications

References 36 publications

Photonic orbital angular momentum in starlight

Photonic orbital angular momentum in starlight

Recent advances in generation of terahertz vortex beams and their applications*

Amplification of OAM radiation by astrophysical masers

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