In the previous app note of Exoplanets, we discussed the major importance and challenges in the development of high-contrast imaging systems in space observatories: researchers worldwide are leading projects for the detection and characterization of habitable exoplanets.
Starlight suppression techniques for the simulation of outer-space conditions have advanced towards the development of coronagraphs. In this scope, the University of Arizona Space Astrophysics lab, led by Professor Douglas has presented their Space Coronagraph Optical Bench (SCoOB) system, combined with extensive work on wavefront control strategies and a description of the future potential of the testbed.[1]
Parallel research perspectives in the medium-resolution regime provided by the Department of Physics and Astronomy from the University of Texas at San Antonio have also led to the development of the Exo-NINJA system: a spectro-imaging platform at the telescope diffraction limit that links the high contrast SCExAO imaging system, with the medium-resolution NINJA spectrograph through a hexagonal multi-mode fiber bundle. [2]
New space coronagraph optical bench: Brief description of the Exo-NINJA at Subaru
Up to date, the integration of optical fibers into ground-based telescope systems in order to couple the light of exoplanets into medium-resolution spectrographs with adaptive optics (AO), has enabled modest detection possibilities of exoplanetary atmospheres and dynamics.
From this perspective, a collaboration between the University of Sydney and the University of Texas at San Antonio results in an innovative design for the Exo-NINJA instrument and its future application on the Subaru Telescope Nasmyth infrared platform. It combines medium-resolution spectroscopy (R=4000) from the NINJA spectrograph, high throughput, and spatial resolution; fed from the SCExAO: the extreme AO coronagraph resulting from the Subaru Coronagraphic Extreme Adaptive Optics project [3]. The link consists of a previously characterized hexabundle: a high-throughput hexagonal multi-mode fiber bundle developed at the Astralis-USyd [Figure 1].
The NINJA instrument is optimized for NIR spectroscopy such that it can be fed to multiple AO systems leading to the versatile utilization of the instrument. Based on a white layout pupil design, it will be part of the 2025 ULTIMATE-START project [4]. Moreover, the NINJA is coupled to the SCExAO through the fiber bundle [Figure 2].
Furthermore, the SCExAO consists of an extreme AO system designed for a wavelength coverage between 0.6 to 2.4 µm, working with a 3000-actuator deformable mirror and wavefront sensing capability in the NIR [5]. This new platform, with upgrades from extreme AO corrections, gives the SCExAO system the potential of more stable PSF and deeper raw contrasts, which opens a new window in the characterizations of exoplanet atmospheres, spectral mapping of gas accretion onto protoplanets and detection of exoplanets at small angular separations from their host stars [2].
Supercontinuum Lasers for Testing the EGRET Testbed
Towards a better understanding of novel concepts before their implementation at Subaru, Dr Currie and Dr ElMorsy from the University of Texas at San Antonio developed a major telescope simulator, with a wavefront sensor: the EGRET testbed [Figure 3]. It comprises two branches: one for thermal phase shifting and the other one for wavefront sensing (WFS).
In the scope of the Exo-NINJA project, the EGRET simulator comprised FYLA´s Iceblink supercontinuum fiber laser for ultra-broad emission in the VIS to NIR. The small beam spot (~2 mm in diameter) with more than 3W of total power passed through different neutral density and color filters, in such a way that the VIS part of the spectrum allowed for bench alignment, whereas the NIR range (0.9 to 1.7 µm) was used for the WFS experiments.
Iceblink Supercontinuum Laser is the Option of Choice in Observatories Worldwide
High-quality laser systems are crucial for advancements in Astronomy and Astrophysics. FYLA´s compromise to science goes beyond what is already established and seeks for the development of the most robust and refined light sources yet, making it an accessible technology to ensure affordable experimental setups.
The Iceblink supercontinuum laser, with more than 3W of total power and the ultra-broad emission that goes from 450 to 2300 nm allows for multiple experiments that are crucial to Astrophysics; from wavefront sensing capabilities to the characterization of optical instruments and alignment measurements.
The small beam diameter of the Iceblink ensures suitable focusing of the light source onto the entrance pupil of your optical system, with a collimation that covers both the VIS and most of the NIR. This ensures proper bench alignment and easier free-space measurements.
Last but not least, the superior power stability of less than 0.5% of std.dev is critical for your laser application, especially when extremely precise measurements are needed for accurate results.
