Characterization and on-sky demonstration of an integrated photonic spectrograph for astronomy

TL;DR

This paper reports the first on-sky demonstration of an integrated photonic spectrograph for astronomy, successfully detecting atmospheric emission lines and characterizing its spectral performance.

Contribution

It presents the first practical on-sky use of an integrated photonic spectrograph, demonstrating its effectiveness for astronomical observations.

Findings

Detected over 27 atmospheric OH emission lines.

Measured spectral resolution of approximately 0.75 nm (R ~ 2100).

Achieved peak efficiency of around 65%.

Abstract

We present results from the first on-sky demonstration of a prototype astronomical integrated photonic spectrograph (IPS) using the Anglo-Australian Telescope near-infrared imaging spectrometer (IRIS2) at Siding Spring Observatory to observe atmospheric molecular OH emission lines. We have succeeded in detecting upwards of 27 lines, and demonstrated the practicality of the IPS device for astronomy. Furthermore, we present a laboratory characterization of the device, which is a modified version of a commercial arrayed-waveguide grating multiplexer. We measure the spectral resolution full-width-half-maximum to be 0.75+/-0.05nm (giving R = 2100+/-150 at 1500nm). We find the free spectral range to be 57.4+/-0.6nm and the peak total efficiency to be ~65%. Finally, we briefly discuss the future steps required to realize an astronomical instrument based on this technology concept.