The Photonic TIGER: a multicore fiber-fed spectrograph

We present a proof of concept compact diffraction limited high-resolution fiber-fed spectrograph by using a 2D multicore array input. This high resolution spectrograph is fed by a 2D pseudo-slit, the Photonic TIGER, a hexagonal array of near-diffraction limited single-mode cores. We study the feasibility of this new platform related to the core array separation and rotation with respect to the dispersion axis. A 7 core compact Photonic TIGER fiber-fed spectrograph with a resolving power of around R~31000 and 8 nm bandwidth in the IR centered on 1550 nm is demonstrated. We also describe possible architectures based on this concept for building small scale compact diffraction limited Integral Field Spectrographs (IFS).Comment: 8 pages, 6 figures, SPIE Astronomical Telescopes and Instrumentation 8450-5

A Multi-Core Fibre Photonic Lantern-Based Spectrograph for Raman Spectroscopy

[EN] We report on the development of a compact (volume approximate to 100 cm(3)), multimode diffraction-limited Raman spectrograph and probe designed to be compact as possible. The spectrograph uses 'off the shelf' optics, a custom 3D-printed two-part housing and harnesses a multi-core fibre (MCF) photonic lantern (multimode to few-mode converter), which slices a large 40 mu m multimode input into a near-diffraction-limited 6 mu m aperture. Our unique design utilises the hexagonal geometry of our MCF, permitting high multimode collection efficiency with near-diffraction-limited performance in a compact design. Our approach does not require a complex reformatter or mask and thus preserves spectral information and throughput when forming the entrance slit of the spectrograph. We demonstrate the technology over the interval 800 nm to 940 nm (200 cm(-1) to 2000 cm(-1)) with a resolution of 0.3 nm (4 cm(-1)), but other spectral regions and resolutions from the UV to the near infrared are also possible. We demonstrate the performance of our system by recording the Raman spectra of several compounds, including the pharmaceuticals paracetamol and ibuprofen.This work was supported in part by the University of Sydney under Grant SREI 2020 and in part by JBH's ARC Laureate Fellowship under Grant FL140100278.Betters, CH.; Bland-Hawthorn, J.; Sukkarieh, S.; Gris-Sánchez, I.; Leon-Saval, SG. (2020). A Multi-Core Fibre Photonic Lantern-Based Spectrograph for Raman Spectroscopy. IEEE Photonics Technology Letters. 32(7):395-398. https://doi.org/10.1109/LPT.2020.2976599S39539832

The CUAVA-2 CubeSat: A Second Attempt to Fly the Remote Sensing, Space Weather Study and Earth Observation Instruments

This paper presents the 6U CubeSat mission conducted by the ARC Training Centre for CubeSats, UAVs, and their Applications (CUAVA) at the University of Sydney. CUAVA-2, the second CubeSat project following the CUAVA-1 mission, builds upon lessons learned from its predecessor. CUAVA-1, the first satellite launched by CUAVA, carried first-generation payloads for earth observation goals and technology demonstrations but experienced communication difficulties. A fault root analysis was performed on CUAVA-1 to inform the design of CUAVA-2. The CUAVA-2 satellite incorporates a hyperspectral imager for applications in agriculture, forestry, coastal and marine environments, urban areas, water hazard assessment, and mineral exploration. It also includes a GPS reflectometry payload for remote sea state determination, as well as secondary payloads for technology demonstration and space weather study. This paper discusses the fault analysis findings, lessons learned, and design inputs from CUAVA-1, showcasing their integration into the CUAVA-2 satellite, which is scheduled for launch in February 2024

The CUAVA-1 CubeSat—A Pathfinder Satellite for Remote Sensing and Earth Observation

In this paper we report a 3U CubeSat named CUAVA-1 designed by the ARC Training Centre for CubeSats, UAVs, and Their Applications (CUAVA). CUAVA, funded by the Australian Research Council, aims to train students, develop new instruments and technology to solve crucial problems, and help develop a world-class Australian industry in CubeSats, UAVs, and related products. The CUAVA-1 project is the Centre’s first CubeSat mission, following on from the 2 Australian satellites INSPIRE-2 and UNSW-EC0 CubeSats that launched in 2017. The mission is designed to serve as a precursor for a series of Earth observations missions and to demonstrate new technologies developed by our partners. We also intend to use the satellite to provide students hands-on experiences and to gain experience for our engineering, science and industry teams for future, more complex, missions

An innovative integral field unit upgrade with 3D-printed micro-lenses for the RHEA at Subaru

In the new era of Extremely Large Telescopes (ELTs) currently under construction, challenging requirements drive spectrograph designs towards techniques that efficiently use a facility's light collection power. Operating in the single-mode (SM) regime, close to the diffraction limit, reduces the footprint of the instrument compared to a conventional high-resolving power spectrograph. The custom built injection fiber system with 3D-printed micro-lenses on top of it for the replicable high-resolution exoplanet and asteroseismology spectrograph at Subaru in combination with extreme adaptive optics of SCExAO, proved its high efficiency in a lab environment, manifesting up to ~77% of the theoretical predicted performance

Single mode, extreme precision doppler spectrographs

The 'holy grail' of exoplanet research today is the detection of an earth-like planet: a rocky planet in the habitable zone around a main-sequence star. Extremely precise Doppler spectroscopy is an indispensable tool to find and characterize earth-like planets; however, to find these planets around solar-type stars, we need nearly one order of magnitude better radial velocity (RV) precision than the best current spectrographs provide. Recent developments in astrophotonics (Bland-Hawthorn & Horton 2006, Bland-Hawthorn et al. 2010) and adaptive optics (AO) enable single mode fiber (SMF) fed, high resolution spectrographs, which can realize the next step in precision. SMF feeds have intrinsic advantages over multimode fiber or slit coupled spectrographs: The intensity distribution at the fiber exit is extremely stable, and as a result the line spread function of a well-designed spectrograph is fully decoupled from input coupling conditions, like guiding or seeing variations (Ihle et al. 2010). Modal noise, a limiting factor in current multimode fiber fed instruments (Baudrand & Walker 2001), can be eliminated by proper design, and the diffraction limited input to the spectrograph allows for very compact instrument designs, which provide excellent optomechanical stability. A SMF is the ideal interface for new, very precise wavelength calibrators, like laser frequency combs (Steinmetz et al. 2008, Osterman et al. 2012), or SMF based Fabry-Perot Etalons (Halverson et al. 2013). At near infrared wavelengths, these technologies are ready to be implemented in on-sky instruments, or already in use. We discuss a novel concept for such a spectrograph.4 page(s

OpenHSI: A Complete Open-Source Hyperspectral Imaging Solution for Everyone

OpenHSI is an initiative to lower the barriers of entry and bring compact pushbroom hyperspectral imaging spectrometers to a wider audience. We present an open-source optical design that can be replicated with readily available commercial-off-the-shelf components, and an open-source software platform openhsi that simplifies the process of capturing calibrated hyperspectral datacubes. Some of the features that the software stack provides include: an ISO 19115-2 metadata editor, wavelength calibration, a fast smile correction method, radiance conversion, atmospheric correction using 6SV (an open-source radiative transfer code), and empirical line calibration. A pipeline was developed to customise the desired processing and make openhsi practical for real-time use. We used the OpenHSI optical design and software stack successfully in the field and verified the performance using calibration tarpaulins. By providing all the tools needed to collect documented hyperspectral datasets, our work empowers practitioners who may not have the financial or technical capability to operate commercial hyperspectral imagers, and opens the door for applications in new problem domains