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2010 CFHT Users Meeting
November 16-18, 2010
ASIAA Auditorium, Taipei, Taiwan

Poster Presentation

ALOHA: Astronomical Light Optical Hybid Analysis

Author(s): Olivier Lai, Damien Ceus, Laurent Delage, Alessandro Tonello, Ludovic Grossard, Francois Reynaud

Presenter: Olivier Lai (Canada France Hawaii Telescope)

Optical fibers and photonics components are going to keep playing an ever increasing role in astronomical optics, especially in the context of coherent light analysis (e.g. adaptive optics, interferometry). Coherent beam transport through single mode fibers (e.g. `OHANA, Perrin et al, 2006) and integrated components (e.g. IONIC, Berger et al, 2003; MAFL, Olivier et al, 2005) have already been demonstrated to provide competitive alternatives, and it is now the turn of non-linear optical component to demonstrate their suitability.

One such possible example is using a sum frequency generation scheme in a non-linear periodically poled lithium niobate (PPLN) crystal, where infrared light can be up-converted to the visible domain, while preserving the coherence properties of the input field. This can be useful at many levels: 1.5um flux can be up-converted to a wavelength range where commercial components such as integrated combiners and photon counting detectors are readily available at visible wavelengths, while relaxing the tolerances on the interferometer to those of the input wavelength. The current experiment on CFHT will allow to demonstrate this as infrared light will be injected into a single mode on AOB and be detected in the red part of the spectrum on ESPaDons. In the longer run, a spectral comb will be used as a pump, which may enable broadband conversion and spectral compression. The main advantage of spectral compression is that monochromatic light reduces the effects of differential dispersion and thus may enable the use of fibered delay lines. Finally, multiple up-conversion right at the telescope could allow thermal infrared interferometry, as visible fibers could then be used to transport 10 micron light using existing components.

Experiments using a PPLN crystal and one of the `Ohana iki telescopes were carried out during June 2010, but the flux level was simply too low to achieve detection of up-conversion. Nonetheless the ALOHA experiment is being developed to measure the conversion efficiency using first the `OHANA iki telescopes and then the AOB system on the 3.6m telescope feeding the ESPaDOns fiber from AOB to measure the up-converted spectrum.

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