Direct (3+1)D laser writing of graded-index optical elements

Abstract

We propose the single-step fabrication of (3+1)D graded-index (GRIN) optical elements by introducing the light exposure as the additional dimension. Following this method, we demonstrate two different optical devices: Volume holograms that are superimposed using angular and peristrophic multiplexing and optical waveguides with a well-defined refractiveindex profile. In the latter, we precisely control the propagating modes via tuning the 3D-printed waveguide parameters and report step-index and graded-index core-cladding transitions.

Laser 3D Printing of Inorganic Free-Form Micro-Optics

“…The LDW 3D nanolithography enables the exposure of a dose-dependent modification depth (degree of conversion/polymerization degree), which can offer a 4D option in tuning the n and at the same time requires even more precise adjustment of laser processing parameters as the geometry is not fully compliant with optical density [29,30]. It was reported that thermal post-curing can serve as an efficient strategy, eliminating the process parameters' sensitivity in the mechanical properties of two-photon polymerized materials [31].…”

Broken-SUSY dynamic reflectionless optical amplifier

“…Luckily for physical feasibility, this dispersion corresponding to the Drude model at high frequencies, is compatible with the Kramers-Kronig relations for fre-quencies sufficiently far from absorption resonances. A good candidate material to realize the proposed device for a portion of the visible spectrum (the one with the right dispersion) would be SiO 2 , also suitable for use in direct laser writing [30,31], which appears as the most directly appropriate technique to realize gradient index spatial distributions. However, a challenge remains which is linked to the possibility to control absorption and gain in space which can be achieved through doping.…”

Brillouin Light Scattering Characterisation of Gray Tone 3D Printed Isotropic Materials

“…In the early age, its use was mainly directed toward electromagnetic applications and it thus was the object of a quest for the highest resolution [1] and the lowest optical losses [3]. This new technology opens the way to new optical metamaterials as simple as 3D dielectrics [4][5][6][7] or to metals by using the printed sample as a mold [8]. Additional efforts have been made to convert dielectrics to conducting parts via atomic layer deposition [9] through simple thermal evaporation.…”

“…It should be noted that the variations of electromagnetic properties such as the refractive index are rather small [12]. However, even such a small but tunable change is very useful and advantageous for manufacturing optical waveguides [6]. Micro-robotics, acoustics and elasticity have also taken advantage of 3D printing technologies for the manufacture of metamaterials via gray tone lithography [10].…”