Spectroscopy is a technique of paramount importance to astronomy, as it enables the chemical composition, distances and velocities of celestial objects to be determined. As the diameter of a ground-based telescope increases, the point-spread- function (PSF) becomes increasingly degraded due to atmospheric seeing. A degraded PSF requires a larger spectrograph slit-width for efficient coupling and current spectrographs for large telescopes are already on the metre scale. This presents numerous issues in terms of manufacturability, cost and stability.
As proposed in 2010 by Bland-Hawthorn et al, one approach which may help to improve spectrograph stability is a guided wave transition, known as a "photonic-lantern". These devices enable the low-loss reformatting of a multimode PSF into a diffraction-limited source (in one direction). This pseudo-slit can then be used as the input to a traditional spectrograph operating at the diffraction limit. In essence, this approach may enable the use of diffraction-limited spectrographs on large telescopes without an unacceptable reduction in throughput.
We have recently demonstrated that ultrafast laser inscription can be used to realize "integrated" photonic-lanterns, by directly writing three-dimensional optical waveguide structures inside a glass substrate. This paper presents our work on developing ultrafast laser inscribed devices capable of reformatting a multimode telescope PSF into a diffraction-limited slit.
|Title of host publication||Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation|
|Editors||R Navarro, CR Cunningham, AA Barto|
|Place of Publication||Bellingham|
|Number of pages||7|
|Publication status||Published - 2014|
|Event||Conference on Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation - Montreal, Canada|
Duration: 23 Jun 2014 → 27 Jun 2014
|Name||Proceedings of SPIE|
|Conference||Conference on Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation|
|Period||23/06/14 → 27/06/14|
- ultrafast laser inscription
- ULTRAFAST LASER INSCRIPTION
- FEMTOSECOND LASER