Frequency stability characterization of a broadband fiber Fabry-Perot interferometer [IMA]

An optical etalon illuminated by a white light source provides a broadband comb-like spectrum that can be employed as a calibration source for astronomical spectrographs in radial velocity (RV) surveys for extrasolar planets. For this application the frequency stability of the etalon is critical, as its transmission spectrum is susceptible to frequency fluctuations due to changes in cavity temperature, optical power and input polarization. In this paper we present a laser frequency comb measurement technique to characterize the frequency stability of a custom-designed fiber Fabry-Perot interferometer (FFP). Simultaneously probing the stability of two etalon resonance modes, we assess both the absolute stability of the etalon and the long-term stability of the cavity dispersion. We measure mode positions with MHz precision, which corresponds to splitting the FFP resonances by a part in 500 and to RV precision of ~1 m/s. We address limiting systematic effects, including the presence of parasitic etalons, that need to be overcome to push the metrology of this system to the equivalent RV precision of 10 cm/s. Our results demonstrate a means to characterize environmentally-driven perturbations of etalon resonance modes across broad spectral bandwidths, as well as motivate the benefits and challenges of FFPs as spectrograph calibrators.

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J. Jennings, S. Halverson, R. Terrien, et. al.
Thu, 2 Mar 17

Comments: 13 pages, 7 figures, submitted to Opt. Express

Photonic Chiral Vortical Effect [CL]

Circularly polarized photons have the Berry curvature in the semiclassical regime. Based on the kinetic equation for such chiral photons, we derive the (non)equilibrium expression of the photon current in the direction of the vorticity. We briefly discuss the relevance of this “photonic chiral vortical effect” in pulsars and rotating massive stars and its possible realization in semiconductors.

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N. Yamamoto
Wed, 1 Mar 17

Comments: 9 pages

Quantum correlation measurements in interferometric gravitational wave detectors [CL]

Quantum fluctuations in the phase and amplitude quadratures of light set limitations on the sensitivity of modern optical instruments. The sensitivity of the interferometric gravitational wave detectors, such as the Advanced Laser Interferometer Gravitational wave Observatory (LIGO), is limited by quantum shot noise, quantum radiation pressure noise, and a set of classical noises. We show how the quantum properties of light can be used to distinguish these noises using correlation techniques. Particularly, in the first part of the paper we show estimations of the coating thermal noise and gas phase noise, hidden below the quantum shot noise in the Advanced LIGO sensitivity curve. We also make projections on the observatory sensitivity during the next science runs. In the second part of the paper we discuss the correlation technique that reveals the quantum radiation pressure noise from the background of classical noises and shot noise. We apply this technique to the Advanced LIGO data, collected during the first science run, and experimentally estimate the quantum correlations and quantum radiation pressure noise in the interferometer for the first time.

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D. Martynov, V. Frolov, S. Kandhasamy, et. al.
Tue, 14 Feb 17

Comments: N/A

Light radiation pressure upon an optically orthotropic surface [CL]

In this paper, we discuss the problem of determination of light radiation pressure force upon an anisotropic surface. The anisotropy of optical parameters is considered to have major and minor axes so the model is called as an orthotropic model. We derive the equations for the force components from the emission, absorption, and reflection, utilizing the modified Maxwell specular-diffuse model. The proposed model can be used as a model of flat solar sail with anisotropically-dispersed wrinkles.

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N. Nerovny
Tue, 7 Feb 17

Comments: 12 pages

An analytic expression for coronagraphic imaging through turbulence. Application to on-sky coronagraphic phase diversity [IMA]

The ultimate performance of coronagraphic high contrast exoplanet imaging systems such as SPHERE or GPI is limited by quasi-static aberrations. These aberrations produce speckles that can be mistaken for planets in the image. In order to design instruments, correct quasi-static aberrations or analyse data, the expression of the point spread function of a coronagraphic instrument in the presence of residual turbulence is most useful. Here we derive an analytic expression for this point spread function that is an extension to coronagraphic imaging of Roddier’s expression for imaging through turbulence. We give a physical interpretation of its structure, we validate it by numerical simulations and we show that it is computationally efficient. Finally, we incorporate this imaging model into a coronagraphic phase diversity method (COFFEE) and validate by simulations that it allows wave-front reconstruction in the presence of residual turbulence. The preliminary results, which give a sub-nanometric precision in the case of a SPHERE-like system, strongly suggest that quasi-static aberrations could be calibrated during observations by this method.

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O. Herscovici-Schiller, L. Mugnier and J. Sauvage
Tue, 31 Jan 17

Comments: This is a pre-copyedited, author-produced PDF of an article accepted for publication in the monthly notices of the royal astronomical society following peer review, MNRAS 2017 slx009

Fabrication and Analysis of Three-Layer All-Silicon Interference Optical Filter with Sub-Wavelength Structure toward High Performance Terahertz Optics [IMA]

We propose an all-silicon multi-layer interference filter composed solely of silicon with sub-wavelength structure (SWS) in order to realize high performance optical filters operating in the THz frequency region with robustness against cryogenic thermal cycling and mechanical damage. We demonstrate fabrication of a three-layer prototype using well-established common micro-electro-mechanical systems (MEMS) technologies as a first step toward developing practical filters. The measured transmittance of the three-layer filter agrees well with the theoretical transmittances calculated by a simple thin-film calculation with effective refractive indices as well as a rigorous coupled-wave analysis simulation. We experimentally show that SWS layers can work as homogeneous thin-film interference layers with effective refractive indices even if there are multiple SWS layers in a filter.

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H. Makitsubo, T. Wada, H. Kataza, et. al.
Tue, 25 Oct 16

Comments: Accepted for publication in J Infrared Milli Terahz Waves. The final publication will be available at Springer via this http URL

Angular Momentum of Twisted Radiation from an Electron in Spiral Motion [CL]

We theoretically demonstrate for the first time that a single free electron in circular/spiral motion emits twisted photons carrying well defined orbital angular momentum along the axis of the electron circulation, in adding to spin angular momentum. We show that, when the electron velocity is relativistic, the radiation field contains harmonic components and the photons of l-th harmonic carry lhbar total angular momentum for each. This work indicates that twisted photons are naturally emitted by free electrons and more ubiquitous in laboratories and in nature than ever been thought.

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M. Katoh, M. Fujimoto, H. Kawaguchi, et. al.
Mon, 10 Oct 16

Comments: N/A