Retinal diseases are the major cause of blindness in industrialized countries. For example, an estimated total of 196 million people will be affected by age related macular degeneration in 2020. While tremendous effort is being made to develop novel therapeutic strategies to rescue retinal neurons and the retinal pigment epithelium, optimal means for evaluating the effects of such treatments are still missing.
Most additive manufacturing methods such as fused-deposition modelling, selective laser melting or stereolithography create objects sequentially one layer at a time. This type of process imposes limitations on the shapes and the materials that can be printed. For example, overhanging structures need additional supports during printing, and soft or elastic materials are difficult to print since they deform as new layers are added.
Currently, neural networks are implemented on electronic chips such as central processing units (CPUs) and graphics processing units (GPUs). However, computational algorithms and more specifically neural networks were also realized with optical systems even though they are far from being as popular as their electronic counterparts. In our laboratory, we demonstrated spatiotemporal nonlinearities inside multimode optical fibers can be used as a neuromorphic neural network and its performance can be comparable to digital neural networks.
3D Printing and Endofabrication A complete method for additive manufacturing –also known as 3D printing- using a multimode optical fiber is demonstrated. Up to now, 3D printing systems have required large optical elements or nozzles in proximity to the built structure. In this system, we use time-gated digital phase conjugation, which consists of two steps: the calibration and the reconstruction step.
Laser-actuated liquid delivery Advanced printing applications require functional inks with complex physical properties. Today there are two main approaches to generate liquid droplets on demand: piezoelectric and thermal actuation. Their jetting mechanism is based on the generation of a pressure pulse to eject a small amount of incompressible liquid through a nozzle, hence producing one or more microdroplets.