Recently, pulsed laser deposition has been utilised to fabricate multi-component thin films and embed

dissimilar materials (polymer and glasses) and nanoparticles from rare earth ions doped glasses target. This review

presents the results of ns/fs-PLD fabrication of the rare-earth-doped multicomponent glass thin films onto semiconductor

and silica substrates for engineering optically active optical waveguides for amplifiers, lasers and integrated sensor

applications. We present the results of waveguide analysis by investigating the surface morphology, cross-section, and

the fraction of crystalline phase using electron microscopy and X-ray diffraction. In addition, other complementary

characteristics such as refractive index, photoluminescence and lifetime, and optical gain properties will be presented.

Ultrashort pulse (USP) laser ablation is gaining popularity as a novel manufacturing technique for brittle materials, enabling the creation of complex freeform shapes that are challenging to produce with conventional optics manufacturing techniques. Freeforms have revolutionized optics manufacturing by providing designers with increased degrees of freedom using non-rotational symmetric components. However, this evolution presents new challenges for manufacturing processes, calling for innovative solutions such as USP ablation. To ensure the industrial viability of areal USP laser machining, it is crucial to not only consider material removal rates but also surface quality and subsurface damage (SSD). Especially for optical applications, harsh quality requirements must be met. This study investigates the SSD patterns of fused silica (FS) and borosilicate glass N-BK7 (BK) processed under different laser wavelengths, beam geometries and processing parameters using high-resolution optical coherence tomography (OCT). It is shown that OCT as non-destructive and 3D evaluation method is well-suited for analysing USP processes. The discovered differences in defect morphology between FS and BK emphasize the importance of selecting appropriate processes and process parameters when working with different materials. Compared to previous studies which used destructive techniques for SSD analysis, OCT revealed higher defects depths of up to 441 µm.

Analysis of defects in optical materials is essential for their applicability in cutting-edge optical components. Since fused silica (FS) counts among the most used materials, deep knowledge about the defects in FS is of high importance. These defects have been routinely identified by studying photoluminescence (PL) emission and its analysis via multiple Gaussian bands. Here we present an extended approach based on the Franck-Condon model to study the defects in FS and the connected pathways of charge carrier relaxation. First, we performed the optical characterization of the FS, including optical absorption, photoluminescence (PL) emission and excitation (PLE), and Fourier-transform infrared (FTIR) and Raman spectroscopy (RS). Based on the analysis of the PLE spectra and vibrational frequencies via RS and FTIR, we created a multi-transition Franck-Condon model, which is able to fully reproduce the PL and PLE spectra. Based on the experimental data and the Franck-Condon fit, we discuss two types of oxygen-deficient centres (ODC) present in this fused silica material and their emission pathways.

Stochastic Si nanostructures for antireflection (AR) fabricated by reactive ion etching (RIE) are presented for use in different spectral ranges. The lithography-free fabrication enables its application on highly curved surfaces. ALD-coatings of Al2O3 of varying thickness can improve the mechanical stability of such structures while keeping their optical functionality. While typical black silicon structures are suitable for application from VIS to NIR, an RIE-based fabrication process for stochastic AR structures in the longer IR and THz range is presented as well.

Over the last 15 years, there have been tremendous progress in the technology of optical interference filters. Nowadays, it is more and more common to fabricate optical interference filters that can combine several tens to several hundreds of layers in order to produce more and more complex optical functions. These progresses are the result of improved multilayer structures modeling and design procedures, the introduction of Virtual Deposition Process, and the development of performant physical vapor deposition machines associated with in-situ optical monitoring. In this paper, we will present actual state-of-the-art of these technologies and some typical examples of filters. We will then present some of the actual challenges and outlook in order to produce more and more performant optical components.