Title :
A thermo-optically tunable flat-lens from visible to near-infrared wavelengths
Author :
Pugh, Jonathan R. ; Stokes, Jamie L. ; Lopez-Garcia, Martin ; Choon-How Gan ; Nash, Geoff R. ; Rarity, John G. ; Cryan, Martin J.
Author_Institution :
Dept. of Electr. & Electron. Eng., Univ. of Bristol, Bristol, UK
Abstract :
We present a beam focusing flat lens for use in the mid-infrared wavelength range. The layer structure used is a 360 nm thick amorphous silicon layer on 200 nm thick aluminium on a 300 μm thick Borosilicate Glass Substrate. An aperture through the Al and a-Si layers is used to excite and enhance the coupling efficiency of a hybrid-surface plasmon polariton/waveguide mode. A second-order grating structure in the surface of the a-Si layer then scatters the propagating hybrid mode to constructively interfere in the far-field with the diffracted light from the narrow aperture to produce a narrow beam. The high dn/dT of amorphous silicon has the potential to enable thermo-optic focusing and steering.
Keywords :
aluminium; amorphous semiconductors; elemental semiconductors; lenses; optical focusing; silicon; thermo-optical devices; Al; Si; amorphous layer; beam focusing flat lens; borosilicate glass substrate; second-order grating structure; size 200 nm; size 300 mum; size 360 nm; thermo-optic focusing; thermo-optic steering; visible to near-infrared wavelengths; Apertures; Couplings; Dielectrics; Dispersion; Gratings; Metals; Surface waves; beam-steering; finite-difference time-domain (FDTD) modeling; flat-lens; infrared; plasmonics;
Conference_Titel :
Transparent Optical Networks (ICTON), 2015 17th International Conference on
Conference_Location :
Budapest
DOI :
10.1109/ICTON.2015.7193568
