Modal noise mitigation for high-precision spectroscopy using a photonic reformatter
arXiv:2001.09211 · doi:10.1093/mnras/staa1950
Abstract
Recently, we demonstrated how an astrophotonic light reformatting device, based on a multicore fibre photonic lantern and a three-dimensional waveguide component, can be used to efficiently reformat the point spread function of a telescope to a diffraction-limited psuedo-slit [arXiv:1512.07309]. Here, we demonstrate how such a device can also efficiently mitigate modal noise -- a potential source of instability in high resolution multi-mode fibre-fed spectrographs). To investigate the modal noise performance of the photonic reformatter, we have used it to feed light into a bench-top near-infrared spectrograph (R {\approx} 9,500, λ {\approx} 1550 nm). One approach to quantifying the modal noise involved the use of broadband excitation light and a statistical analysis of how the overall measured spectrum was affected by variations in the input coupling conditions. This approach indicated that the photonic reformatter could reduce modal noise by a factor of six when compared to a multi-mode fibre with a similar number of guided modes. Another approach to quantifying the modal noise involved the use of multiple spectrally narrow lines, and an analysis of how the measured barycentres of these lines were affected by variations in the input coupling. Using this approach, the photonic reformatter was observed to suppress modal noise to the level necessary to obtain spectra with stability close to that observed when using a single mode fibre feed. These results demonstrate the potential of using photonic reformatters to enable efficient multi-mode spectrographs that operate at the diffraction limit and are free of modal noise, with potential applications including radial velocity measurements of M-dwarfs.
13 pages, 9 figures (including appendix)
References in corpus (25)
- Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
- Detection of Planetary Transits Across a Sun-like Star
- A terrestrial planet candidate in a temperate orbit around Proxima Centauri
- Kepler Mission Design, Realized Photometric Performance, and Early Science
- The Occurrence Rate of Small Planets around Small Stars
- State of the Field: Extreme Precision Radial Velocities
- The Photonic Lantern
- A stellar-mass-dependent drop in planet occurrence rates
- Detecting Planets Around Very Low Mass Stars with the Radial Velocity Method
- WASP-19b: the shortest period transiting exoplanet yet discovered
- Searches for Point-like and extended neutrino sources close to the Galactic Centre using the ANTARES neutrino Telescope
- The Occurrence Rate of Earth Analog Planets Orbiting Sunlike Stars
- Lines and continuum sky emission in the near infrared: observational constraints from deep high spectral resolution spectra with GIANO-TNG
- Suppression of Fiber Modal Noise Induced Radial Velocity Errors for Bright Emission-Line Calibration Sources
- The Photonic TIGER: a multicore fiber-fed spectrograph
- Modal Noise Mitigation through Fiber Agitation for Fiber-fed Radial Velocity Spectrographs
- Efficient photonic reformatting of celestial light for diffraction-limited spectroscopy
- Modal noise in an integrated photonic lantern fed diffraction-limited spectrograph
- Detection of GeV -ray emission in the direction of HESS J1731-347 with Fermi-LAT
- Multicore fibre photonic lanterns for precision radial velocity science
- Preliminary results on the characterization and performances of ZBLAN fiber for infrared spectrographs
- Simulation and Optimization of an Astrophotonic Reformatter
- A Multi-Core Fibre Photonic Lantern Based Spectrograph for Raman Spectroscopy
- Precision velocimetry planet hunting with PARAS: Current performance and lessons to inform future extreme precision radial velocity instruments
- Modal noise characterisation of a hybrid reformatter