The Santa cruz Extreme Adaptive optics Lab (SEAL) is a visible/near-infrared wavelength testbed designed to support technology development for high contrast imaging on large, segmented, ground-based telescopes. SEAL saw first light in 2021 as a transmissive, visible-wavelength AO testbed. In this paper, we present four major upgrades to SEAL: (1) the testbed has been rebuilt with custom off-axis parabolic mirrors, enabling operation in both near-infrared and visible wavelengths; (2) the suite of wavefront sensors now includes a Shack-Hartmann, transmissive four-sided pyramid, vector-Zernike, and, in the muirSEAL testbed, a photonic lantern; (3) the testbed includes a vector-vortex coronagraph and will soon include a hybrid astrophotonic coronagraph; (4) in addition to its original Keck-heritage RTC, SEAL now includes two additional control software packages: Catkit, originally developed for the HiCAT testbed at the Space Telescope Science Institute, and the RTC Compute And Control for Adaptive Optics (CACAO), originally designed for Subaru/SCExAO. We discuss the performance of the testbed after the reflective rebuild and on-going technology development work at SEAL.

The SCALES instrument is a high-contrast imager and integral field spectrograph that operates in the infrared wavelength and is intended to be utilized behind W.M. Keck Observatory's adaptive optics system. The instrument operates over a broad wavelength range from 1.0 to 5.0 mu m. The instrument includes a microlens array-based integral field spectrograph that is used with slicer optics and allows for low (R similar to 35 - 250) and moderate (R similar to 2000 - 6500) spectral resolution spectroscopy. We have implemented end-to-end modeling of the SCALES instrument optics using both geometric optics and physical optics. This analysis has been useful to understand the spectral formats, spectral resolution, and point spread functions. We have also modeled the geometric PSF from lenslets and combined it with the diffraction effects to model the crosstalk between the closely spaced lenslet spectra. The psf modeling are being integrated with the SCALES simulator to simulate realistic data products that are being used to develop the SCALES data pipeline.

Liger is a next-generation near-infrared (0.81 - 2.45 mu m) integral field spectrograph (IFS) and imaging camera for the W. M. Keck Observatory (WMKO) adaptive optics (AO) system. The instrument concept originated by coupling designs from WMKO AO instruments and the future Thirty Meter Telescope IRIS spectrograph. Liger is designed for the Keck I telescope to operate behind the upcoming Keck All-sky Precision Adaptive optics (KAPA) system. The imaging camera sequentially feeds an IFS that makes use of slicer assembly for the coarsest sampling (75 mas and 150 mas per spaxel) and lenslet array (14 mas and 31 mas per spaxel) for diffraction-limited sampling. The imaging camera makes use of off-axis parabolas and a Hawaii-2RG detector to achieve a 14 mas/pixel plate scale and 20.5 '' x20.5 '' field of view. The IFS offers a range of spectral resolving power of R=4,000 10,000 and yields large fields of view for an AO-fed IFS. Liger will enable new science by providing enhanced capabilities, including higher spectral resolving power, access to shorter wavelengths, and larger fields of view than any current or planned ground- or space-based IFS system. Liger will be able to unlock previously inaccessible science across a wide range of the cosmos, such as dark matter substructure, supermassive black holes, the Galactic Center, exoplanet atmospheres, and the time-variable Solar System. We present the overall design of the Liger subsystems and review unique science drivers.

We report on the design and status of the slicing unit of SCALES (Slicer Combined with an Array of Lenslets for Exoplanet Spectroscopy), which sits behind the lenslet array and produces a pseudoslit suitable for higher dispersion than is achievable with a lenslet alone. Typical lenslet-based integral field spectrographs achieve high spatial resolution (but at the expense of spectral resolution), and slicers can achieve high spatial and spectral resolution (but at the expense of field of view), and additionally require extreme care in design and fabrication to avoid introducing aberrations through the slicer and spectrograph optics that can reduce the overall performance. Our 'slenslit' (SLiced LENlet pseudoSLIT) combines the benefits of the lenslet array, which samples the field of view, and the slicer, which rearranges the field of view, to produce diffraction-limited, high spatial resolution spectra of exoplanets. SCALES' diffraction-limited integral field spectrograph operates from 1 to 5 microns behind the W.M. Keck Observatory's AO system, and coronagraphic masks unlock the high contrast needed to observe and characterize exoplanets. The SCALES slenslit opens up new parameter space heretofore untapped by rearranging a small patch of lenslets into a pseudoslit before being dispersed at moderate spectral resolution (R similar to 2500 - 7500) over the SCALES bandpass while preserving the spatial resolution offered by the Keck AO system. The slenslit is being built in collaboration with the University of Durham's Centre for Advanced Instrumentation.

The Infrared Imaging Spectrograph (IRIS) is a diffraction-limited instrument designed for the Thirty Meter Telescope (TMT) through an international collaboration. IRIS works in tandem with the Narrow-Field InfraRed Adaptive Optics System (NFIRAOS) and covers a near-infrared spectral range of 0.84 to 2.4 microns. IRIS and NFIRAOS will be the instruments used to demonstrate first light at TMT. IRIS incorporates a wide-field Imager with a fixed plate scale of 4 milliarcseconds (mas), and an Integral Field Spectrograph (IFS) offering four plate scales that range from 4 mas to 50 mas. In 2021, the major subsystems of IRIS went through final design reviews. This paper provides an update on IRIS design and outlines the plan for its fabrication, integration, and delivery to TMT for first light.

Liger is an adaptive optics (AO) fed imager and integral field spectrograph (IFS) designed to take advantage of the Keck All-sky Precision Adaptive-optics (KAPA) upgrade to the Keck I telescope. Liger adapts the design of the InfraRed Imaging Spectrograph (IRIS) for the Thirty Meter Telescope (TMT) to Keck by implementing a new imager and re-imaging optics. The performance of the imager is critical as it sequentially feeds the spectrograph and contains essential components such as the pupil wheel, filter wheel, and pupil viewing camera. We present the design and structural analysis of the Liger imager optical assembly including static, modal, and thermal simulations. We present the fabrication as well as the full assembly and characterization plan. The imager will be assembled bench-top in a clean room utilizing a coordinate-measuring machine (CMM) for warm alignment. To ensure optimal performance, the imager will be characterized in a test cryostat before integration with the full Liger instrument. This comprehensive approach to characterization ensures the precision and reliability of the imager, enhancing the observational capabilities of Liger and W.M. Keck Observatory.

The challenges met in the design of cryogenic instruments for infrared astronomy involve a certain level of uncertainty in the dynamic responses of mechanical components when going from warm to cold. These types of responses include differential contraction of unlike materials, slipping between contact surfaces, and the potential for warping of mechanical components depending on stresses inherently present in the material. This paper will go over the design and manufacturing principles practiced to mitigate these types of variables that would result in detriment to performance. The optics, mounts, and alignment features detailed in this paper are to be used for the Slicer Combined with an Array of Lenslets for Exoplanet Spectroscopy (SCALES) instrument, a 2-5 micron coronagraphic integral field spectrograph under construction for Keck Observatory. Design principles, such as monolithic mount structures, a bolt-and-go approach to mounts, flexure designs for the optical substrates, cryogenic compatible alignment features, and the approach taken to athermalize a titanium tip/tilt stage present in the forward optics section will be explained in detail in this paper. Manufacturing principles and techniques are discussed in this paper concerning the types of tolerances and features called out along with machining conditions to meet the technical requirements of the SCALES instrument.

The Keck Adaptive Secondary Mirror (KASM) project is planned as a core component of adaptive optics (AO) improvements for the Keck 1 telescope. KASM will provide image quality enhancements to all instrument locations, while also enabling correction of the ground layer turbulence for wide field instruments, and the foundation for a visible light diffraction-limited AO system. KASM is intended to replace the original telescope secondary mirror (M2) and will support both adaptive optics correction and purely passive (seeing-limited) observing modes of operation. The concept for KASM has been developed considering both voice coil and hybrid variable reluctance actuator technology. A metrology and calibration setup for off-sky use has been developed to verify KASM performance both prior to installation and once at the telescope.

The Keck Adaptive Secondary Mirror (KASM) project will broaden the use of adaptive optics on the Keck I telescope by integrating the correction device into the secondary mirror. By replacing the static secondary with a high-actuator count convex deformable mirror, image sharpening will be available to all instrument ports. The KASM optical surface will be a thin shell polished to match the optical prescription of the existing Keck I secondary mirror to within a few microns. The final correction of the optical shape will be achieved with control of the ASM's actuators. The calibration and verification equipment (CAVE) will be an optical metrology package designed to verify that the delivered KASM has the correct optical figure. CAVE will also be used to verify and calibrate the actuator motion, both spatially and temporally, forming the basis for the actuator influence functions used in closed-loop operations. CAVE will be used during testing at the University of California Observatories optical laboratory, as well as during commissioning and periodic verification at the W.M. Keck Observatory, necessitating a robust and repeatable kinematic mounting arrangement. We describe the design of CAVE and develop a concept for laboratory and telescope facility operations and calibration.

Liger is an adaptive optics (AO)-fed imager and integral field spectrograph (IFS) designed for W.M. Keck Observatory. Liger will be coupled with the Keck All-sky Precision Adaptive-optics (KAPA) upgrade which will allow both systems to fully utilize their capabilities to maximize scientific return for the broader community. Liger features a custom-designed imaging camera that sequentially feeds the pristine AO image to two select-able integral field spectrograph (IFS) modes: an image slicer for coarse spatial sampling and a lenslet array for finer spatial scales. Both IFS modes utilize a final "camera" three-mirror anastigmat (TMA) and a Hawaii 4RG detector for data collection. This paper will discuss the assembly, integration, and testing (AIT) of the Liger instrument sub-assemblies. The project is currently in the first of two-fabrication phases where we are manufacturing, assembling, and testing the complete imager system, the IFS camera TMA, grating turret mechanism, and the IFS re-imaging optics mechanisms. The second fabrication phase will include the final fabrication and assembly of the IFS and science cryostat. An integration phase will follow where the full instrument is assembled and integrated into the science cryostat. Once complete the Liger instrument will be shipped to Hawaii for final assembly, integration, and verification at W.M. Keck Observatory.