Towards a photonic mid-infrared nulling interferometer in chalcogenide glass

Gretzinger, Thomas; Gross, Simon; Arriola, Alexander; Withford, Michael J.

doi:10.1364/oe.27.008626

Cited by 27 publications

(23 citation statements)

References 40 publications

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“…Chalcogenide glasses, including GLS, have shown particular promise -they are highly transparent at mid-IR wavelengths and have successfully been used to create waveguides and evanescent couplers using laser direct write (Labadie et al 2012;Arriola et al 2014;. Prototype nulling-interferometer beamcombiners have also been produced using direct-write with this glass (Gretzinger et al 2019), as well as planar lithographic technology (Kenchington Goldsmith et al 2016). Other materials such as various different types of fluoride and chalcogenide glasses and fluoride crystals have also been investigated (Arriola et al 2017).…”

Section: Resultsmentioning

confidence: 99%

First on-sky demonstration of an integrated-photonic nulling interferometer: the GLINT instrument

Norris

Cvetojevic

Lagadec

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The characterisation of exoplanets is critical to understanding planet diversity and formation, their atmospheric composition and the potential for life. This endeavour is greatly enhanced when light from the planet can be spatially separated from that of the host star. One potential method is nulling interferometry, where the contaminating starlight is removed via destructive interference. The GLINT instrument is a photonic nulling interferometer with novel capabilities that has now been demonstrated in onsky testing. The instrument fragments the telescope pupil into sub-apertures that are injected into waveguides within a single-mode photonic chip. Here, all requisite beam splitting, routing and recombination is performed using integrated photonic components. We describe the design, construction and laboratory testing of our GLINT pathfinder instrument. We then demonstrate the efficacy of this method on sky at the Subaru Telescope, achieving a null-depth precision on sky of ∼ 10 −4 and successfully determining the angular diameter of stars (via their null-depth measurements) to milliarcsecond accuracy. A statistical method for analysing such data is described, along with an outline of the next steps required to deploy this technique for cutting-edge science.

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Section: Resultsmentioning

confidence: 99%

First on-sky demonstration of an integrated-photonic nulling interferometer: the GLINT instrument

Norris

Cvetojevic

Lagadec

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…Mid-IR regions at longer wavelength are better suited due to more favourable contrast ratios between the star and planet ( ), as well as encompassing interesting geo- and bio-signatures. Efforts are also being undertaken to push the direct-write to platforms further into the red to access these wavelengths of interest (Gretzinger et al 2019). Drawing such threads together offers the prospect for significant advances in recovery of direct detection exoplanetary signals for the next-generation extremely large telescopes or interferometric arrays.…”

Section: Discussionmentioning

confidence: 99%

The GLINT South testbed for nulling interferometry with photonics: Design and on-sky results at the Anglo-Australian Telescope

Lagadec

Norris

Gross

et al. 2021

Publ. Astron. Soc. Aust.

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In 1978, Bracewell suggested the technique of nulling interferometry to directly image exoplanets which would enable characterisation of their surfaces, atmospheres, weather, and possibly determine their capacity to host life. The contrast needed to discriminate starlight reflected by a terrestrial-type planet from the glare of its host star lies at or beyond a forbidding $10^{-10}$ for an exo-Earth in the habitable zone around a Sun-like star at near-infrared wavelengths, necessitating instrumentation with extremely precise control of the light. Guided Light Interferometric Nulling Technology (GLINT) is a testbed for new photonic devices conceived to overcome the challenges posed by nulling interferometry. At its heart, GLINT employs a single-mode nulling photonic chip fabricated by direct-write technology to coherently combine starlight from an arbitrarily large telescope at 1 550 nm. It operates in combination with an actuated segmented mirror in a closed-loop control system, to produce and sustain a deep null throughout observations. The GLINT South prototype interfaces the 3.9-m Anglo-Australian Telescope and was tested on a sample of bright Mira variable stars. Successful and continuous starlight injection into the photonic chip was achieved. A statistical model of the data was constructed, enabling a data reduction algorithm to retrieve contrast ratios of about $10^{-3}$ . As a byproduct of this analysis, stellar angular diameters that were below the telescope diffraction limit ( $\sim$ 100 mas) were recovered with 1 $\sigma$ accuracy and shown to be in agreement with literature values despite working in the seeing-limited regime. GLINT South serves as a demonstration of the capability of direct-write photonic technology for achieving coherent, stable nulling of starlight, which will encourage further technological developments towards the goal of directly imaging exoplanets with future large ground based and space telescopes.

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“…The typical glass systems for astrophotonics include silica glass, borosilicate glass, chalcogenide glass, and fluoride glass. 78,80,[157][158][159][160][161][162][163][164] For the demonstration, integrated photonic lanterns were fabricated, which can couple multimode light to an array of singlemode WGs. 78 These integrated devices [named photonic dicers, as shown in Fig.…”

Section: Astrophotonicsmentioning

confidence: 99%

“…14(b), nulling interferometers were written in gallium lanthanum sulfur (GLS) glass via multiscans of 5.1 MHz fs laser. 162 In this two-port interferometer, the Y-splitters direct half of the light into the outer photometric channels, with another half directed into the two inner channels for interferometric interaction. The starlight is nulled by destructive interference in the coupling region.…”

Section: Astrophotonicsmentioning

confidence: 99%

“…Unfortunately, the loss performance of WGs in these mid-infrared glasses (e.g., propagation loss >0.2 dB∕cm in chalcogenide glass and >0.3 dB∕cm in fluoride glass) is worse than that in silica and borosilicate glasses (that <0.2 dB∕cm). [162][163][164] In fact, the propagation loss will increase in the 3D WG lattices. Second, it is also still difficult to fabricate 3D WG arrays with identical waveguiding performance in each one, especially when the WG number and depth variation are large.…”

Section: Astrophotonicsmentioning

confidence: 99%

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Photonic circuits written by femtosecond laser in glass: improved fabrication and recent progress in photonic devices

et al. 2021

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Integrated photonics is attracting considerable attention and has found many applications in both classical and quantum optics, fulfilling the requirements for the ever-growing complexity in modern optical experiments and big data communication. Femtosecond (fs) laser direct writing (FLDW) is an acknowledged technique for producing waveguides (WGs) in transparent glass that have been used to construct complex integrated photonic devices. FLDW possesses unique features, such as three-dimensional fabrication geometry, rapid prototyping, and single step fabrication, which are important for integrated communication devices and quantum photonic and astrophotonic technologies. To fully take advantage of FLDW, considerable efforts have been made to produce WGs over a large depth with low propagation loss, coupling loss, bend loss, and highly symmetrical mode field. We summarize the improved techniques as well as the mechanisms for writing high-performance WGs with controllable morphology of cross-section, highly symmetrical mode field, low loss, and high processing uniformity and efficiency, and discuss the recent progress of WGs in photonic integrated devices for communication, topological physics, quantum information processing, and astrophotonics. Prospective challenges and future research directions in this field are also pointed out.

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Towards a photonic mid-infrared nulling interferometer in chalcogenide glass

Cited by 27 publications

References 40 publications

First on-sky demonstration of an integrated-photonic nulling interferometer: the GLINT instrument

First on-sky demonstration of an integrated-photonic nulling interferometer: the GLINT instrument

The GLINT South testbed for nulling interferometry with photonics: Design and on-sky results at the Anglo-Australian Telescope

Photonic circuits written by femtosecond laser in glass: improved fabrication and recent progress in photonic devices

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