Laboratory Demonstration of Spatial-Coherence Analysis of a Blackbody through an Up-Conversion Interferometer

Abstract

In the field of high resolution imaging in astronomy, we experimentally demonstrate the spatial-coherence analysis of a blackbody using an up-conversion interferometer in the photon counting regime. The infrared radiation of the blackbody is converted to a visible one in both arms of the interferometer thanks to the sum-frequency generation processes achieved in Ti-diffused periodically poled lithium niobate waveguides. The coherence analysis is performed through a dedicated imaging stage which mimics a classical telescope array analyzing an astrophysical source. The validity of these measurements is confirmed by the comparison with spatial-coherence analysis through a reference interferometer working at infrared wavelengths.

ALOHA—Astronomical Light Optical Hybrid Analysis

“…-Sensitivity tests at the Mauna Kea observatory: first stellar light conversion using a 20 cm C8 telescope [5]. -Operating an up-conversion interferometer with a blackbody source: in lab demonstration of the performances of the up-conversion interferometer on the most incoherent source fitting the real astronomical conditions [9]. -Large bandwidth conversion and spectral compression: when checking the nonlinear crystal properties, one of the main features is the spectral filtering performed by the sum frequency generation process.…”

Multichannel spectral mode of the ALOHA up-conversion interferometer

“…Convincing preliminary results have been obtained in laboratory with a blackbody source (Gomes et al 2014), and recently on the sky (Darré et al 2016) through a collaboration with the CHARA Array team (ten Brummelaar et al 2005). These studies have been performed in the H astronomical band to take advantage of the mature technology dedicated to optical telecommunications.…”

1.064-μm-band Up-conversion Single-photon Detector

“…Various SPDs working at different spectral windows have been developed, including silicon avalanche photodiode (APD) [1][2][3], InGaAs/InP APDs [4,5], up-conversion SPD [6,7], and superconducting SPD [8,9]. SPDs have extensive applications in quantum communication systems [10], optical time domain reflectrometry (OTDR) [11,12], single-photon-level spectrometer [13,14], high resolution imaging in astronomy [15] and so forth.…”