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International audience; The study of cold or obscured, red astrophysical sources can significantly benefit from adaptive optics (AO) systems employing infrared (IR) wavefront sensors. One particular area is the study of exoplanets around M-dwarf stars and planet formation within protoplanetary disks in star-forming regions. Such objects are faint at visible wavelengths but bright enough in the IR to be used as a natural guide star for the AO system. Doing the wavefront sensing at IR wavelengths enables high-resolution AO correction for such science cases, with the potential to reach the contrasts required for direct imaging of exoplanets. To this end, a new near-infrared pyramid wavefront sensor (PyWFS) has been added to the Keck II AO system, extending the performance of the facility AO system for the study of faint red objects. We present the Keck II PyWFS, which represents a number of firsts, including the first PyWFS installed on a segmented telescope and the first use of an IR PyWFS on a 10-m class telescope. We discuss the scientific and technological advantages offered by IR wavefront sensing and present the design and commissioning of the Keck PyWFS. In particular, we report on the performance of the Selex Avalanche Photodiode for HgCdTe InfraRed Array detector used for the PyWFS and highlight the novelty of this wavefront sensor in terms of the performance for faint red objects and the improvement in contrast. The system has been commissioned for science with the vortex coronagraph in the NIRC2 IR science instrument and is being commissioned alongside a new fiber injection unit for NIRSPEC. We present the first science verification of the system-to facilitate the study of exoplanets around M-type stars.

The Keck Planet Imager and Characterizer (KPIC) is an upgrade to the Keck II adaptive optics system enabling high contrast imaging and high-resolution spectroscopic characterization of giant exoplanets in the mid-infrared (2-5 microns). The KPIC instrument will be developed in phases. Phase I entails the installation of an infrared pyramid wavefront sensor (PyWFS) based on a fast, low-noise SAPHIRA IR-APD array. The ultra-sensitive infrared PyWFS will enable high contrast studies of infant exoplanets around cool, red, and/or obscured targets in star forming regions. In addition, the light downstream of the PyWFS will be coupled into an array of single-mode fibers with the aid of an active fiber injection unit (FIU). In turn, these fibers route light to Keck's high-resolution infrared spectrograph NIRSPEC, so that high dispersion coronagraphy (HDC) can be implemented for the first time. HDC optimally pairs high contrast imaging and high-resolution spectroscopy allowing detailed characterization of exoplanet atmospheres, including molecular composition, spin measurements, and Doppler imaging. We will provide an overview of the instrument, its science scope, and report on recent results from on-sky commissioning of Phase I. We will discuss plans for optimizing the instrument to seed designs for similar modes on extremely large telescopes.

We are building a next-generation laser adaptive optics system, Robo-AO-2, for the UH 2.2-m telescope that will deliver robotic, diffraction-limited observations at visible and near-infrared wavelengths in unprecedented numbers. The superior Maunakea observing site, expanded spectral range and rapid response to high-priority events represent a significant advance over the prototype. Robo-AO-2 will include a new reconfigurable natural guide star sensor for exquisite wavefront correction on bright targets and the demonstration of potentially transformative hybrid AO techniques that promise to extend the faintness limit on current and future exoplanet adaptive optics systems., Comment: 15 pages

We present a design of a thermal-infrared optimized adaptive optics system for the TMT 30-meter telescope. The approach makes use of an adaptive secondary but during an initial implementation contains a more conventional ambient-temperature optical relay and deformable mirror. The conventional optical relay is used without sacrificing the thermal background by using multiple off-axis laser guide stars to avoid a warm dichroic in the common path. Three laser guide stars, equally spaced 75" off axis, and a "conventional" 30×30 deformable mirror provide a Strehl > 0.9 at wavelengths longer than 10 microns and the LGS beams can be passed to the LGS wavefront sensors with pickoff mirrors while a one-arcminute field is passed unvignetted to the science instrument and NGS WFSs. The overall design is relatively simple with a wavefront correction similar to existing high-order systems (e.g. 30×30) but still provides competitive performance over the higher-order TMT NIR AO design at wavelengths as short as 3 microns due to its reduced thermal emissivity. We present our figures of merit and design considerations within the context of the science drivers for high-spectral resolution NIR/MIR spectroscopy at 5-28 microns on a 30-meter ground-based telescope.