Detecting photons with orbital angular momentum in extended astronomical objects: application to solar observations

Abstract

Context. The orbital angular momentum (OAM) of the photon is a property of light from astronomical objects that has not yet been measured. We propose a method of measuring the OAM spectrum of light from an extended natural source, the Sun. Relating the OAM spectrum of different solar areas to its structures could lead to a novel remote sensing technique. Aims. We present a method for measuring the OAM spectrum of solar photons. Methods. The THEMIS telescope is being used with a novel phase-diversity technique. A spatial light modulator is placed on one pupil image, and an ad-hoc optical setup allows the measurement of two simultaneous phase-diverse images in the same CCD, with equal optical paths. Results. Preliminary results show that very good seeing is mandatory for this kind of observation. The method works in the laboratory, and good seeing conditions in the 2010 campaign are being awaited.

Signal detection for spectroscopy and polarimetry

“…Finally, we propose that this technique could be applied to the detection of the ultimate property of light, its orbital angular momentum, from astrophysical objects (Harwit 2003), whose detection, if present, is going to be challenging (Uribe-Patarroyo et al 2011).…”

Primum Non Torquere∗ - Photon Orbital Angular Momentum in Astronomy

“…Measuring the POAM spectrum provides an independent measurement of mass and spin. Uribe-Patarroyo et al attempted POAM detection of ±1 POAM transitions by solar photons [14]. Berkhout and Beijersbergen have developed an algorithm to measure POAM with a multipoint interferometer [15].…”

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

“…Demonstration of the second is more demanding. Whereas observation of astronomical sources relies on measurement of the intensity, wavelength, polarization, or coherence (imaging) of electromagnetic waves to interrogate remote physical systems, for instance gravitational interactions from images, none use the recently enumerated property of POAM (Uribe-Patarroyo et al 2011). We present the first such observations in Sect.…”

“…For example, Tamburini et al (2011) found that photons could be imparted with orbital angular A&A 556, A130 (2013) momentum through interaction with a Kerr black hole. Also, Uribe-Patarroyo et al (2011) discuss solar photons carrying orbital angular momentum and their use in comparing properties of different solar regions. Berkhout & Beijersbergen (2009) discussed use of a multipoint interferometer as a method of identifying optical vortices in astronomical sources and elsewhere ) described an optical system utilizing two custom optical components for detection of multiple OAM modes simultaneously.…”