Luminescence confocal microscopy of 3D components of photonic integrated circuits fabricated by two-photon photopolymerization

Abstract

Direct laser writing (DLW) lithography has been growing rapidly and is widely used for photonic integrated circuit (PIC) fabrication manufacturing in micro optics and photonics to fabricate 2D, 2.5D, and 3D components due to low cost, high precision and no need for mask exposure. There is a huge demand for PIC for instruments, systems and complexes of optoelectronic navigation instrumentation, as well as for use in a wide range of areas: biophotonics, signal detection and processing, robotics, telecommunications. The technique of DLW is based on nonlinear interaction between laser radiation and the photoresist medium (two photon absorption and consequent photopolymerization). The traditional method for studying the morphology of obtained PIC elements is the method of scanning electron microscopy. An alternative method of morphological analysis of PICs obtained by two photon absorption-direct laser writing (TPA-DLW) is proposed here - scanning luminescence confocal microscopy method. It is an effective method that enables obtaining conclusive information on the geometrical parameters as the morphology properties as well as the luminescence information.