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ULTIMATE-Subaru is a next large facility instrument project at Subaru telescope. We will develop a 14x14 sq. arcmin wide-field near-infrared (NIR) imager and a multi-object spectrograph with the aid of a ground- layer adaptive optics system (GLAO), which will uniformly improve the seeing by a factor of 2 over a wide field of view up to ~20 arcmin in diameter. We have developed system modeling of the GLAO and wide-field NIR instruments to define the system level requirements flow down from science cases and derive the system performance budgets based on the GLAO end-to-end numerical simulation and optical system models of the telescope and wide-field NIR science instruments. In this paper, we describe the system performance modeling of ULTIMATE-Subaru and present an overview of the requirements flow down.

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is a high-contrast imaging system installed at the 8-m Subaru Telescope on Maunakea, Hawaii. Due to its unique evolving design, SCExAO is both an instrument open for use by the international scientific community, and a testbed validating new technologies, which are critical to future high-contrast imagers on Giant Segmented Mirror Telescopes (GSMTs). Through multiple international collaborations over the years, SCExAO was able to test the most advanced technologies in wavefront sensors, real-time control with GPUs, low-noise high frame rate detectors in the visible and infrared, starlight suppression techniques or photonics technologies. Tools and interfaces were put in place to encourage collaborators to implement their own hardware and algorithms, and test them on-site or remotely, in laboratory conditions or on-sky. We are now commissioning broadband coronagraphs, the Microwave Kinetic Inductance Detector (MKID) Exoplanet Camera (MEC) for high-speed speckle control, as well as a C-RED ONE camera for both polarization differential imaging and IR wavefront sensing. New wavefront control algorithms are also being tested, such as predictive control, multi-camera machine learning sensor fusion, and focal plane wavefront control. We present the status of the SCExAO instrument, with an emphasis on current collaborations and recent technology demonstrations. We also describe upgrades planned for the next few years, which will evolve SCExAO —and the whole suite of instruments on the IR Nasmyth platform of the Subaru Telescope— to become a system-level demonstrator of the Planetary Systems Imager (PSI), the high-contrast instrument for the Thirty Meter Telescope (TMT).

Currently, two AO systems are operated at Subaru Telescope: AO188, which is a facility AO system, and SCExAO, which is a PI-type ExAO system operated behind AO188. In the next 5 year, large-scale upgrades are performed on AO188 for improving the AO performance and operation of AO188 and SCExAO and for the technical demonstration toward the future wide-field ULTIMATE-Subaru GLAO system at Subaru and an ExAO system at TMT, PSI. We are planning to upgrade the real-time control system, the LGS system, and bimorph DM. Also, a new NIR WFS, a LTAO WFS unit, and a beam-switching system will be installed into the Nasmyth IR platform. The installation of the LTAO WFS unit is a part of the ULTIMATE-START project, which implement a LTAO mode into AO188 and demonstrates technologies for the ULTIMATE-Subaru GLAO system. ULTIMATE-Subaru project aims at developing a next-generation, wide-field GLAO system and wide-field NIR instruments for Subaru Telescope, whose first light will be in FY2025.

ULTIMATE-Subaru is a next large facility instrument project at Subaru telescope. We will develop a 14x14 arcmin2 wide-field near-infrared (1.0-2.5μm) imager and a multi-object spectrograph with the aid of a ground- layer adaptive optics system (GLAO), which will uniformly improve the seeing by a factor of 2 over a wide field of view up to ~20 arcmin in diameter. The expected spatial resolution by the GLAO correction is about 0.2 arcsec FWHM in K-band under moderate seeing conditions at Subaru telescope. ULTIMATE-Subaru will provide a unique capability to realize wide-field and high spatial resolution survey observations in near infrared in the era of TMT. In this paper, we introduce the project overview including the GLAO and near-infrared instrument conceptual design. We also describe the future wide-field strategy at Subaru telescope with ULTIMATE-Subaru together with HSC and PFS.

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is an extremely modular high-contrast instrument installed on the Subaru telescope in Hawaii. SCExAO has a dual purpose. Its position in the northern hemisphere on a 8-meter telescope makes it a prime instrument for the detection and characterization of exoplanets and stellar environments over a large portion of the sky. In addition, SCExAO's unique design makes it the ideal instrument to test innovative technologies and algorithms quickly in a laboratory setup and subsequently deploy them on-sky. SCExAO benefits from a first stage of wavefront correction with the facility adaptive optics AO188, and splits the 600-2400 nm spectrum towards a variety of modules, in visible and near infrared, optimized for a large range of science cases. The integral field spectrograph CHARIS, with its J, H or K-band high-resolution mode or its broadband low-resolution mode, makes SCExAO a prime instrument for exoplanet detection and characterization. Here we report on the recent developments and scientific results of the SCExAO instrument. Recent upgrades were performed on a number of modules, like the visible polarimetric module VAMPIRES, the high-performance infrared coronagraphs, various wavefront control algorithms, as well as the real-time controller of AO188. The newest addition is the 20k-pixel Microwave Kinetic Inductance Detector (MKIDS) Exoplanet Camera (MEC) that will allow for previously unexplored science and technology developments. MEC, coupled with novel photon-counting speckle control, brings SCExAO closer to the final design of future high-contrast instruments optimized for Giant Segmented Mirror Telescopes (GSMTs)., 12 pages, 9 figures, conference proceedings (SPIE Astronomical telescopes and instrumentation 2018)

The AO188 Single Conjugate facility AO system at Subaru Telescope delivers diffraction-limited images in near-IR in natural and laser guide star modes. We have recently started a major upgrade of AO188 to fulfill the high performance requirements of its downstream instruments, including the Subaru Coronagraphic Extreme-AO. The first phase of this upgrade started in 2017 with the integration of a new real time computer (RTC) and real time system (RTS) CACAO(https://github.com/CACAO-org/CACAO), an open-source real-time software for adaptive optics developed collaboratively and used extensively by the SCExAO instrument. This major upgrade will enable loop optimization, predictive control and include diagnosis tools, therefore improving the performance and stability of AO188 and its downstream instrument module. This paper introduces the architecture of the new RTS describing the different steps we followed to adapt CACAO to our AO interfaces and aging hardware, in preparation of our first engineering tests on-sky achieved successfully on July 23rd 2018.

The compute and control for adaptive optics (cacao) package is an open-source modular software environment for real-time control of modern adaptive optics system. By leveraging many-core CPU and GPU hardware, it can scale up to meet the demanding computing requirements of current and future high frame rate, high actuator count adaptive optics (AO) systems. cacao’s modular design enables both simple/barebone operation, and complex full-featured AO control systems. cacao’s design is centered on data streams that hold real-time data in shared memory along with a synchronization mechanism for computing processes. Users and programmers can add additional features by coding modules that interact with cacao’s data stream format. We describe cacao’s architecture and its design approach. We show that accurate timing knowledge is key to many of cacao’s advanced operation modes. We discuss current and future development priorities, including support for machine learning to provide real-time optimization of complex AO systems.

We report the current status of the laser guide star upgrade at Subaru Telescope with a new, more powerful TOPTICA/MPBC laser. While we recycle many of our existing components, such as laser launch telescope, we need to design a new mirror-based laser relay system to replace the current fiber-based relay to accommodate the high power beam. The laser unit has been delivered to Subaru office in March 2018 and installed in a testing lab in June 2018. We describe the preliminary design and its requirements and report future plans. This upgrade will not only improve our current adaptive optics system but also be the first step toward the future laser tomography and ground layer adaptive optics system at Subaru Telescope.

Exoplanet imaging requires excellent wavefront correction and calibration. At the Subaru telescope this is achieved us- ing the 188-element facility adaptive optics system(AO188) feeding the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument; a multipurpose instrument built to deliver high contrast images of planets and disks around nearby stars. AO188 offers coarse correction while SCExAO performs fine correction and calibration of 1000 modes. The full system achieves 90%Strehl Ratio in H-band and diffraction limited images. A new Real Time Computer allowing higher performance between SCExAO and AO188 is currently implemented. Future upgrades will include a new Pyramid Wavefront Sensor and (64x64) DM to achieve extreme AO correction inside AO188. We are progressing in the development of predictive control and sensor fusion algorithms across the system to improve performance and calibration. With the new upgrades, SCExAO will be able to image giant planets in reflected light with Subaru and validate technologies necessary to image habitable Earth-like planets with the Thirty Meter Telescope (TMT).

This paper presents the overview of on-going and future adaptive optics (AO) activities at the Subaru telescope on the top of Maunakea in Hawaii. Currently, two AO systems are running at the Subaru telescope: AO188, a facility single-conjugate AO system with a bimorph deformable mirror and a curvature wavefront sensor with 188 elements, and SCExAO, an additional extreme AO system operating behind AO188 and specialized for exoplanet sciences. We recently started AO188 upgrade project to improve its performance for the next 5-10 years, which will also help improving SCExAO performance. These upgrades are in line with a development for the ULTIMATE-Subaru ground layer AO system.

We report on the conceptual design study done for the Ground Layer Adaptive Optics system of the ULTIMATE-Subaru project. This is an ambitious instrument project, providing GLAO correction in a square field of view of 14 arcmin on a side, aiming to deliver improved seeing at the near infrared wavelength. Its client instruments are an imager and multi-IFU spectrograph at Cassegrain and a Multi-Object spectrograph at Nasmyth. In this paper, we introduce the ULTIMATE-Subaru project overview and its science case and report the results of the GLAO performance prediction based on the numerical simulation and conceptual design of the wavefront sensor system.

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is a multipurpose high-contrast imaging platform designed for the discovery and detailed characterization of exoplanetary systems and serves as a testbed for high-contrast imaging technologies for ELTs. It is a multi-band instrument which makes use of light from 600 to 2500nm allowing for coronagraphic direct exoplanet imaging of the inner 3 lambda/D from the stellar host. Wavefront sensing and control are key to the operation of SCExAO. A partial correction of low-order modes is provided by Subaru's facility adaptive optics system with the final correction, including high-order modes, implemented downstream by a combination of a visible pyramid wavefront sensor and a 2000-element deformable mirror. The well corrected NIR (y-K bands) wavefronts can then be injected into any of the available coronagraphs, including but not limited to the phase induced amplitude apodization and the vector vortex coronagraphs, both of which offer an inner working angle as low as 1 lambda/D. Non-common path, low-order aberrations are sensed with a coronagraphic low-order wavefront sensor in the infrared (IR). Low noise, high frame rate, NIR detectors allow for active speckle nulling and coherent differential imaging, while the HAWAII 2RG detector in the HiCIAO imager and/or the CHARIS integral field spectrograph (from mid 2016) can take deeper exposures and/or perform angular, spectral and polarimetric differential imaging. Science in the visible is provided by two interferometric modules: VAMPIRES and FIRST, which enable sub-diffraction limited imaging in the visible region with polarimetric and spectroscopic capabilities respectively. We describe the instrument in detail and present preliminary results both on-sky and in the laboratory., Comment: Accepted for publication, 20 pages, 10 figures

Contrast limit for the direct imaging of extrasolar planets from ground based adaptive optics (AO) observations is set by the presence of static and slow-varying aberrations in the optical path that lead to the science instrument. To complement the otherwise highly successful angular differential imaging (ADI) technique toward small angular separation, we propose to employ additional wavefront control to modulate the diffraction. This flexible approach introduces enough diversity to discriminate genuine structures of the observed target from spurious diffraction features in the image. One possible implementation of such form of coherence differential imaging (CDI) is a speckle nulling algorithm that iteratively suppresses diffraction features inside a region constrained by the number of active elements of the deformable mirror modulating the wavefront, and the coronagraph. This paper presents on-sky results obtained with this approach, on the Subaru Coronagraphic Extreme AO (SCExAO) instrument.

International audience; The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is one of a handful of extreme adaptive optics systems set to come online in 2014. The extreme adaptive optics correction is realized by a combination of precise wavefront sensing via a non-modulated pyramid wavefront sensor and a 2000 element deformable mirror. This system has recently begun on-sky commissioning and was operated in closed loop for several minutes at a time with a loop speed of 800 Hz, on ~150 modes. Further suppression of quasi-static speckles is possible via a process called "speckle nulling" which can create a dark hole in a portion of the frame allowing for an enhancement in contrast, and has been successfully tested on-sky. In addition to the wavefront correction there are a suite of coronagraphs on board to null out the host star which include the phase induced amplitude apodization (PIAA), the vector vortex, 8 octant phase mask, 4 quadrant phase mask and shaped pupil versions which operate in the NIR (y-K bands). The PIAA and vector vortex will allow for high contrast imaging down to an angular separation of 1 lambda/D to be reached; a factor of 3 closer in than other extreme AO systems. Making use of the left over visible light not used by the wavefront sensor is VAMPIRES and FIRST. These modules are based on aperture masking interferometry and allow for sub-diffraction limited imaging with moderate contrasts of ~100-1000:1. Both modules have undergone initial testing on-sky and are set to be fully commissioned by the end of 2014.

High performance coronagraphic imaging of faint structures around bright stars at small angular separations requires fine control of tip, tilt and other low order aberrations. When such errors occur upstream of a coronagraph, they results in starlight leakage which reduces the dynamic range of the instrument. This issue has been previously addressed for occulting coronagraphs by sensing the starlight before or at the coronagraphic focal plane. One such solution, the coronagraphic low order wave-front sensor (CLOWFS) uses a partially reflective focal plane mask to measure pointing errors for Lyot-type coronagraphs. To deal with pointing errors in low inner working angle phase mask coronagraphs which do not have a reflective focal plane mask, we have adapted the CLOWFS technique. This new concept relies on starlight diffracted by the focal plane phase mask being reflected by the Lyot stop towards a sensor which reliably measures low order aberrations such as tip and tilt. This reflective Lyot-based wavefront sensor is a linear reconstructor which provides high sensitivity tip-tilt error measurements with phase mask coronagraphs. Simulations show that the measurement accuracy of pointing errors with realistic post adaptive optics residuals are approx. 10^-2 lambda/D per mode at lambda = 1.6 micron for a four quadrant phase mask. In addition, we demonstrate the open loop measurement pointing accuracy of 10^-2 lambda/D at 638 nm for a four quadrant phase mask in the laboratory., Comment: 9 Pages, 11 Figures, to be published in PASP June 2014 issue

This paper presents the first on-sky demonstration of speckle nulling, which was achieved at the Subaru Telescope in the context of the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) Project. Despite the absence of a high-order high-bandwidth closed-loop AO system, observations conducted with SCExAO show that even in poor-to-moderate observing conditions, speckle nulling can be used to suppress static and slow speckles even in the presence of a brighter dynamic speckle halo, suggesting that more advanced high-contrast imaging algorithms developed in the laboratory can be applied to ground-based systems., Comment: 5 figures, accepted for publication by PASP

Micro-Electro-Mechanical Systems (MEMS) deformable mirrors (DMs) are widely utilized in astronomical Adaptive Optics (AO) instrumentation. High precision open-loop control of MEMS DMs has been achieved by developing a high accuracy DM model, the Fast Iterative Algorithm (FIA), a physics-based model allowing precise control of the DM shape. Accurate open-loop control is particularly critical for the wavefront control of High- Contrast Imaging (HCI) instruments to create a dark hole area free of most slow and quasi-static speckles which remain the limiting factor for direct detection and imaging of exoplanets. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system is one of these high contrast imaging instruments and uses a 1024-actuator MEMS deformable mirror (DM) both in closed-loop and open-loop. The DM is used to modulate speckles in order to distinguish (i) speckles due to static and slow-varying residual aberrations from (ii) speckles due to genuine structures, such as exoplanets. The FIA has been fully integrated into the SCExAO wavefront control software and we report the FIA’s performance for the control of speckles in the focal plane.

ELTs will offer angular resolution around 10mas in the near-IR and unprecedented sensitivity. While direct imaging of Earth-like exoplanets around Sun-like stars will stay out of reach of ELTs, we show that habitable planets around nearby M-type main sequence stars can be directly imaged. For about 300 nearby M dwarfs, the angular separation at maximum elongation is at or beyond 1 e/D in the near-IR for an ELT. The planet to star contrast is 1e-7 to 1e-8, similar to what the upcoming generation of Extreme-AO systems will achieve on 8-m telescopes, and the potential planets are sufficiently bright for near-IR spectroscopy. We show that the technological solutions required to achieve this goal exist. For example, the PIAACMC coronagraph can deliver full starlight rejection, 100% throughput and sub-e/D IWA for the EELT, GMT and TMT pupils. A closely related coronagraph is part of SCExAO on Subaru. We conclude that large ground-based telescopes will acquire the first high quality spectra of habitable planets orbiting M-type stars, while future space mission(s) will later target F-G-K type stars.

In 2009 our group started the integration of the SCExAO project, a highly exi ble, open platform for highcontrast imaging at the highest angular resolution, inserted between the coronagr aphic imaging camera HiCIAOand the 188-actuator AO system of Subaru. In its rst version, SCExAO combines a ME MS-based wavefrontcontrol system feeding a high performance PIAA-based coronagraph. This paper present s some of the imagesobtained during the rst engineering observations conducted with SCExAO in 2011: di ract ion limited imagingin the visible as well as PIAA coronagraphy in the near infrared; along with t he wavefront control strategies tobe tested on sky during the next round of SCExAO observations, scheduled in the Fall 2 012. 1. INTRODUCTION The last ten years of extrasolar planet research have been dominated by indirect detect ions techniques of radialvelocity (RV) and photometric transit. The observational bias of these techniq ues initially led to the discoveryof a large population of short period planets, exhibiting surprisingly divers e dynamics. Only as the time baselineincreases, do RV and transits become more and more sensitive to long period pla nets of wide orbital separation.

The PIAA is a now well demonstrated high contrast technique that uses an intermediate remapping of the pupil for high contrast coronagraphy (apodization), before restoring it to recover classical imaging capabilities. This paper presents the first demonstration of complete speckle control loop with one such PIAA coronagraph. We show the presence of a complete set of remapping optics (the so-called PIAA and matching inverse PIAA) is transparent to the wavefront control algorithm. Simple focal plane based wavefront control algorithms can thus be employed, without the need to model remapping effects. Using the Subaru Coronagraphic Extreme AO (SCExAO) instrument built for the Subaru Telescope, we show that a complete PIAA-coronagraph is compatible with a simple implementation of a speckle nulling technique, and demonstrate the benefit of the PIAA for high contrast imaging at small angular separation., 6 figures, submitted to PASP

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system uses advanced coronagraphic technique for high contrast imaging of exoplanets and disks as close as 1 lambda/D from the host star. In addition to unusual optics, achieving high contrast at this small angular separation requires a wavefront sensing and control architecture which is optimized for exquisite control and calibration of low order aberrations. The SCExAO system was thus designed to include the wavefront sensors required for bias-free high sensitivity and high speed wavefront measurements. Information is combined from two infrared wavefront sensors and a fast visible wavefront sensors to drive a single MEMS type deformable mirror mounted on a tip-tilt mount. The wavefront sensing and control architecture is highly integrated with the coronagraph system.

In 2009 our group started the integration of the SCExAO project, a highly flexible, open platform for high contrast imaging at the highest angular resolution, inserted between the coronagraphic imaging camera HiCIAO and the 188-actuator AO system of Subaru. In its first version, SCExAO combines a MEMS-based wavefront control system feeding a high performance PIAA-based coronagraph. It also includes a coronagraphic low-order wavefront sensor, a non-redundant aperture mask and a visible imaging mode, all of them designed to take full advantage of the angular resolution that an 8-meter telescope has to offer. SCExAO is currently undergoing commissioning, and this paper presents the first on-sky results acquired in August 2011, using together Subaru's AO system, SCExAO and HiCIAO.

We present new on-sky results for the Subaru Coronagraphic Extreme Adaptive Optics imager (SCExAO) verifying and quantifying the contrast gain enabled by key components: the closed-loop coronagraphic low-order wavefront sensor (CLOWFS) and focal plane wavefront control (“speckle nulling”). SCExAO will soon be coupled with a high-order, Pyramid wavefront sensor which will yield > 90% Strehl ratio and enable 106–107 contrast at small angular separations allowing us to image gas giant planets at solar system scales. Upcoming instruments like VAMPIRES, FIRST, and CHARIS will expand SCExAO's science capabilities.