Here we present an optical cross-dispersion setup for an astrophotonic spectrograph in the near-IR H-band (1460-1630 nm). In this spectrograph, the arrayed waveguide grating (AWG) chip acts as the main dispersing element. An AWG produces a 1D spectrum with overlapping spectral orders, and we designed a cross-dispersion setup that can cross-disperse these overlapping spectral orders perpendicular to the 1D spectral output. This setup consists of a collimating lens, a grating, and a focusing lens. The cross-dispersed 2D spectrum is then imaged onto a near-IR detector array. The AWG we used for this project has a spectral resolution of (lambda/delta lambda) of similar to 1000 and a free spectral range of 10 nm. An on-sky solar test was performed and analyzed, demonstrating the potential of this setup.

HARMONI is the adaptive optics assisted, near-infrared and visible light integral field spectrograph for the Extremely Large Telescope (ELT). A first light instrument, it provides the work-horse spectroscopic capability for the ELT. As the project approaches its Final Design Review milestone, the design of the instrument is being finalized, and the plans for assembly, integration and testing are being detailed. We present an overview of the instrument’s capabilities from a user perspective, provide a summary of the instrument’s design, including plans for operations and calibrations, and provide a brief glimpse of the predicted performance for a specific observing scenario. The paper also provides some details of the consortium composition and its evolution since the project commenced in 2015.

The High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph (HARMONI) will be one of the instruments installed on ESO's 39-meter Extremely Large Telescope (ELT) at first light. The instrument will operate from 0.47 - 2.45 mu m with Delta lambda/lambda = 3,000 - 17,000. On-sky spatial pixels (spaxels) are divided between four spectrographs, each equipped with 11 transmission diffraction gratings to cover the ranges of wavelengths and spectral resolutions. These spectrographs will be cooled to similar to 140 K to decrease thermal radiation at longer wavelengths. In all configurations, the diffraction grating will lose a greater fraction of scientific light than any other single optic in the instrument. Additionally, manufacturers are often unable to measure the fraction of transmitted light at HARMONI's longest wavelengths. For these reasons, we have developed a setup to measure the efficiencies of transmission diffraction gratings across HARMONI's bandpass. The setup uses modulated signals, a single detector, and a lock-in amplifier to minimize sources of systematic errors. A modified version of this setup may be used to measure stray light. These setups and initial results are presented.