Over the past decades, advances in metamaterial and metasurfaces inspired innovation in many imaging systems. Contrary to conventional optics where ray tracing and a Fourier transform exactly predict light propagation, those approaches are no longer valid in the case of metasurfaces and hybrid glass-metasurface coated lenses. We will discuss in this presentation our latest results and observations to develop new tools that can be incorporated within a lens design software. Analytical solution developed for this implementation will also be discussed. With these new tools, lens design can think of using metasurface within an optimized optical system
Among the multiple techniques proposed to obtain continuous tuning of a laser, many involve a wavelength selective element that needs to be rotated in order to select the output wavelength. Such methods usually require more optical components than the technique proposed in this paper. Our group uses the line spacing variation in a custom-engineered chirped grating to achieve a mode-hop free modification of the output wavelength of a semiconductor laser by a simple translation of the grating. The useful beam out-coupled through the 0th-order is propagating in a constant direction for any tuned wavelength. The variation in the line space also induces a focal effect in the axis perpendicular to the grooves; it is exploited to compensate a part of the beam divergence in the external cavity. Moreover, a transverse focal effect from the holographic grating is introduced for improved reinjection in the laser chip. With this simple configuration, it has been possible to obtain a continuous tuning of a semiconductor laser over 10 nm at an average wavelength close to 1540 nm. The output power of such a laser was near 8 mW and quite stable over all the tuning range. Fine adjustments are still made to obtain a greater tuning range.