Abstract
We demonstrate solar spectrum measurement in the visible-near-infrared
region by integrated waveguide spectral lens (WSL). Light through the
chip is dispersed and focused on a camera placed at the designed
distance without any free-space lens. Commercial polymer materials with
low propagation loss near visible region are chosen for wafer-scale
fabrication. The solar radiation is coupled to a fiber via a home-made
setup and the captured light is transmitted over ~50 m
to the lab, where the spectrum is examined by two WSL chips for
broadband and fine analysis, respectively. The observed O2 (687.7 nm,
761.9 nm) and H2O (718.4 nm) absorption lines are in good agreement with
the results from a commercial optical spectral analyzer and the
literature. This experiment proves the feasibility of using planar WSL
chips as low-cost and versatile components for the development of
compact and portable spectrometer equipment.