Using private funding, we have developed photonic near-infrared (1.4 -
1.6 microns) spectrometers where the dispersing optics are replaced by
miniature (~1 cubic-centimeter) arrayed waveguide gratings imprinted
using buried silicon nitride (``nano-core'') technology, the leading
solution for low-loss waveguides. We have also developed highly
sophisticated photonics filters using complex waveguide Bragg
gratings, produced on the same platform technology as the photonic
spectrometers and equally small. These prototypes have been fabricated
and tested using the state-of-the-art facilities of the Maryland
NanoCenter and AstroPhotonics Lab, and the results of these tests have
been published in refereed publications and conference proceedings.
APRA funding is now used to develop the next generation of photonics
spectrometers and filters for astrophysics and space science
applications. We will (1) broaden the wavelength range to 1 - 1.7
microns, (2) increase the spectral resolving power of our photonic
spectrometers from R ~ 1500 to 3000, (3) experiment with the aspect
ratio of the waveguide cross-section and overall design of the Braggs
and arrayed waveguide gratings to make them polarization-independent,
and (4) increase the overall throughput of these gratings to >70% at 1
- 1.7 microns by changing the deposition method of the cladding
material (silica) and reducing the scattering losses with the use of a
newly commissioned electron beam writer that delivers higher
resolution (down to a few nm instead of ~8 nm). Two graduate students,
already trained in the techniques relevant to this project, will lead
the optimization, fabrication, and testing of these optoelectronic
components. Up to three undergraduate students will also be involved
with the research. A wide swath of astrophysical research, from
spectroscopic studies of the distant universe to searches for
biosignatures in the atmospheres of exoplanets, stands to benefit from
these miniature spectrometers and filters on board future NASA
balloon, CubeSat, Explorer, Probe-, Flagship-, and Surveyor class
missions. The technical by-products of this effort will also offer
benefits in fields far beyond astronomy, such as medicine, human
science, petrochemistry, space geo-science, and quantum computing and
communication.