Holographic Optical Method for Exoplanet Spectroscopy

When Galileo observed Jupiter through a so-called "spy glass," it became a telescope. Much as moons circle Jupiter, there are planets orbiting distant stars. A search has started to find and categorize these exoplanets, but our telescopes may not be equal to the task.

The extraordinary demands made in exoplanet discovery include huge telescope apertures of unprecedented angular resolution and sensitivity. However, that ballgame cannot even begin without a method to dim the host star and remove its glare. As if that were not trouble enough, habitable planet discovery necessitates exquisite spectrographic capability.

HOMES is a space telescope designed to address all of these criteria. Its unorthodox double dispersion architecture employs a holographic optical element (HOE) as a primary objective in conjunction with a novel secondary interferometric spectrograph. This gives the HOE telescope thousands of views of a planetary system, each with unique spectral lines. When the lines are combined, planetary spectral signatures may be of adequate precision to predict exoplanet habitability. The star is dimmed by destructive interference by mixing a wave with itself after collection. HOMES can be scaled to any length from a cylindrical roll that conforms to a rocket payload fairing.

In 2012 NASA's Innovative Advanced Concepts program (NIAC) funded a study of HOMES. Read SPIE papers and our Phase I Final Report to NIAC on the concept.


The High Étendue Multiple Object Spectrographic Telescope

Here is an entirely new type of telescope with the promise of unprecedented performance made possible by a novel design concept. The use of a diffraction grating as its primary objective in combination with a secondary spectrometer results in a multiple object spectrometer capable of taking millions of ultra-high resolution spectrograms per observation cycle. The MOST's flat grazing exodus configuration could conceivably achieve kilometer scale apertures.

Terrestial designs feature a very low wind profile and no moving parts during observations. Airborne embodiments can operate inside a sealed cabin at high altitude. In space deployment, the design uses a flat gossamer membrane that is maintained by inertial forces. For an observatory on the moon, light-weight components with low operational maintenance favor it over mirrors.

Read our papers for the International Society for Optical Engineering (SPIE) and the American Institute for Aeronautics and Aerospace (AIAA).

Report to the NASA Institute for Advanced Concepts (2007)

PDF icon Dittoscope - Overview (2002)

PDF icon Terrestrial Observatory (2002)

PDF icon Space Deployment (2002)

PDF icon Some Answers for Critics (2004)

PDF icon Gossamer Membrane (2007)

PDF icon Airborne (2008)

PDF icon Terrestrial 02 (2008)

PDF icon Million Object Spectrograph (2008)

PDF icon Error Analysis 01 (2008)

PDF icon Gossamer Membrane Demo (2009)

PDF icon  POHOE (2011)

PDF icon  Conservation of Etendue (2014)