Enhanced high-dispersion coronagraphy with KPIC phase II: design, assembly and status of sub-modules

Jovanović, Nemanja; Calvin, Benjamin; Porter, Michael; Schofield, Tobias; Wang, Jason; Roberts, Mitsuko; Ruane, Garreth; Wallace, J. Kent; Bartos, Randall; Pezzato, Jacklyn; Colborn, Jennah K.; Delorme, Jacques-Robert; Echeverri, Daniel; Mawet, Dimitri; Bond, C.; Cetre, Sylvain; Lilley, Scott; Ragland, Sam; Wizinowich, Peter; Jensen-Clem, Rebecca

doi:10.1117/12.2563107

Cited by 13 publications

(16 citation statements)

References 13 publications

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“…The second phase planned to deploy in late 2021 will contain extramodules: an atmospheric dispersion compensator (ADC), phase-induced amplitude apodization optics, a high order deformable mirror, and coronagraphs, whose goal will be to improve the overall throughput for the planet light while reducing star light leakage to reduce overall integration times. [29][30][31] In this paper, we present a detailed overview of the first phase FIU and its performance.…”

Section: Keck Planet Imager and Characterizermentioning

confidence: 99%

“…These two optical relays that are mostly empty during the first phase of the project will be populated in phase two. 30,31 After the two relays, a tip-tilt mirror (TTM) is situated in the pupil plane of the instrument for aligning the target with the fiber and fine tuning the pointing onto the fibers (L). The TTM (Physik Instrumente, S-330.8SL) is a piezo mechanism, which offers a field steering of AE2.4 arc sec in two axes.…”

Section: Injection Modulementioning

confidence: 99%

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Keck Planet Imager and Characterizer: a dedicated single-mode fiber injection unit for high-resolution exoplanet spectroscopy

Delorme

Jovanović

Echeverri

et al. 2021

J. Astron. Telesc. Instrum. Syst.

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The Keck Planet Imager and Characterizer (KPIC) is a purpose-built instrument to demonstrate technological and instrumental concepts initially developed for the exoplanet direct imaging field. Located downstream of the current Keck II adaptive optic (AO) system, KPIC contains a fiber injection unit (FIU) capable of combining the high-contrast imaging capability of the AOs system with the high dispersion spectroscopy capability of the current Keck high resolution infrared spectrograph (NIRSPEC). Deployed at Keck in September 2018, this instrument has already been used to acquire high-resolution spectra (R > 30;000) of multiple targets of interest. In the near term, it will be used to spectrally characterize known directly imaged exoplanets and low-mass brown dwarf companions visible in the northern hemisphere with a spectral resolution high enough to enable spin and planetary radial velocity measurements as well as Doppler imaging of atmospheric weather phenomena. Here, we present the design of the FIU, the unique calibration procedures needed to operate a single-mode fiber instrument and the system performance. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Keck Planet Imager and Characterizermentioning

confidence: 99%

Section: Injection Modulementioning

confidence: 99%

Keck Planet Imager and Characterizer: a dedicated single-mode fiber injection unit for high-resolution exoplanet spectroscopy

Delorme

Jovanović

Echeverri

et al. 2021

J. Astron. Telesc. Instrum. Syst.

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“…The wavelength dependence of α p is dominated by differential atmospheric refraction changing the apparent sky position of the planet, and this effect changes slowly as a function of wavelength. The use of an atmospheric dispersion corrector in KPIC Phase II will mitigate this effect on α p (Wang et al 2020a;Jovanovic et al 2020). We did not find chromatic optical aberrations in the system to be measurable for inclusion in α p .…”

Section: Wavelength Calibrationmentioning

confidence: 99%

“…Lastly, future planned upgrades to KPIC (Pezzato et al 2019;Jovanovic et al 2020) are designed to improve the coupling of planet light, reduce the coupling of star light, and mitigate the instrument thermal background. As we are limited by thermal background noise currently, increasing the amount of planet light reaching the detector and reducing the amount of thermal background photons will directly translate into improvements in the SNR of KPIC observations.…”

Section: Future Prospectsmentioning

confidence: 99%

Detection and Bulk Properties of the HR 8799 Planets with High-resolution Spectroscopy

Wang

Ruffio

Morris

et al. 2021

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Using the Keck Planet Imager and Characterizer (KPIC), we obtained high-resolution (R∼35,000) K-band spectra of the four planets orbiting HR 8799. We clearly detected H 2 O and CO in the atmospheres of HR 8799 c, d, and e, and tentatively detected a combination of CO and H 2 O in b. These are the most challenging directly imaged exoplanets that have been observed at high spectral resolution to date when considering both their angular separations and flux ratios. We developed a forward modeling framework that allows us to jointly fit the spectra of the planets and the diffracted starlight simultaneously in a likelihood-based approach and obtained posterior probabilities on their effective temperatures, surface gravities, radial velocities, and spins. We measured v sin(i) values of

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“…The general trends in our results will be independent of pupil geometry, but for the purpose of this work we assume the Keck pupil. We assume a deformable mirror (DM) with 30 × 30 actuators across the pupil, in line with current "extreme AO" systems and similar to the ∼1,000-element DM which will be introduced to Keck as part of the phase II of the KPIC project [29]. The control law is handled using a basic leaky-integrator scheme.…”

Section: Adaptive Opticsmentioning

confidence: 99%

Design considerations of photonic lanterns for diffraction-limited spectrometry

2021

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The coupling of large telescopes to astronomical instruments has historically been challenging due to the tension between instrument throughput and stability. Light from the telescope can either be injected wholesale into the instrument, maintaining high throughput at the cost of point-spread function (PSF) stability, or the time-varying components of the light can be filtered out with single-mode fibers (SMFs), maintaining instrument stability at the cost of light loss. Today, the field of astrophotonics provides a potential resolution to the throughput-stability tension in the form of the photonic lantern (PL): a tapered waveguide which can couple a timevarying and aberrated PSF into multiple diffraction-limited beams at an efficiency that greatly surpasses direct SMF injection. As a result, lantern-fed instruments retain the stability of SMF-fed instruments while increasing their throughput. To this end, we present a series of numerical simulations characterizing PL performance as a function of lantern geometry, wavelength, and wavefront error (WFE), aimed at guiding the design of future diffraction-limited spectrometers. These characterizations include a first look at the interaction between PLs and phase-induced amplitude apodization (PIAA) optics. We find that Gaussian-mapping beam-shaping optics can enhance coupling into 3-port lanterns but offer diminishing gains with larger lanterns. In theand -band (0.97-1.35 μm) region, with moderately high WFE (∼10% Strehl ratio), a 3-port lantern in conjunction with beam-shaping optics strikes a good balance between pixel count and throughput gains. If pixels are not a constraint, and the flux in each port will be dominated by photon noise, then larger port count lanterns will provide further coupling gains due to a greater resilience to tip-tilt errors. Finally, we show that lanterns can maintain high operating efficiencies over large wavelength bands where the number of guided modes at the lantern entrance drops, if care is taken to minimize the attenuation of weakly radiative input modes.

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Enhanced high-dispersion coronagraphy with KPIC phase II: design, assembly and status of sub-modules

Cited by 13 publications

References 13 publications

Keck Planet Imager and Characterizer: a dedicated single-mode fiber injection unit for high-resolution exoplanet spectroscopy

Keck Planet Imager and Characterizer: a dedicated single-mode fiber injection unit for high-resolution exoplanet spectroscopy

Detection and Bulk Properties of the HR 8799 Planets with High-resolution Spectroscopy

Design considerations of photonic lanterns for diffraction-limited spectrometry

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