Optical imaging of internal organs is a crucial tool for advanced medical imaging applications, particularly for minimally invasive procedures like bronchoscopy. Currently, the shape and size of the lens systems are restricted by manufacturing limitations. Incorporating imaging optics at the end of a coherent fibre bundle (diameter 350 µm) offers the potential for far-field imaging of the distal lung reducing the overall catheter size to ~1.8 mm. This enhancement would facilitate real-time 3D reconstruction for spatial airway mapping during navigation. A femtosecond direct laser writing system is incorporated to fabricate micro-lenses with high optical quality. To ensure robustness and reusability, these microlenses will be directly printed onto a fused silica end cap, manufactured using ultrafast laser-assisted etching (ULAE). This talk presents an overview of the methods used to fabricate a functional imaging system to be incorporated with a novel bronchoscope, addressing the challenges and innovations involved in its development.

Two-photon Polymerization (2PP) is probably the technique which offers more degrees of freedom for the fabrication of complex 3D structures with submicrometric resolutions. However, it is known that the main drawback of 2PP is the reduced throughput. Several optical approaches can be used to overcome such issue, like the use of Diffractive Optical Elements, Interference optical setups, or Spatial Light Modulators (SLMs); being SLMs the only elements that allow increasing the productivity of 2PP, since the use of DOEs and Interference setups is limited to the fabrication of periodic structures

The work presented here shows our latest results for the fabrication of 3D features with lateral sizes well below the micron range using a combined phase-amplitude laser beam modulation of the laser beam. The combination of optimized scanning strategies with the modification of the laser optical wavefront shape will be presented as a feasible alternative for high throughput 2PP.

In this work we present our recent results on multi-photon polymerization (MPP) using mode-locked diode lasers. While conventional MPP systems use titanium:sapphire lasers or fiber lasers, our goal is to replace these laser types with monolithically mode-locked diode lasers. Since diode lasers are much more compact, cost effective and allow for direct modulation without the need for additional components such as AOMs this will allow us to build a compact and cost effective MPP system. The diode laser used for this work emits mode-locked laser pulses at 780 nm at a pulse repetition rate of 6.6 GHz, an average power >1.5 W, and pulse length > 3 ps. We will demonstrate how to operate the laser, find the best point of operation for 2PP and present printed structures and an analysis of the writing process using these laser sources.

We present an innovative approach to holographic layer-by-layer 3D printing by adding temporally and spacially shaped femtosecond pulses elements to the overall design. 2D printed patterns are generated using a Digital Micromirror Device (DMD), which also at the same time spreads the spectrum of the visible (515 nm) fiber laser used. Projecting these patterns with a 4-f system gives reduced intensity temporally while at the print plane simultaneously bringing the spacial and temporal elements to a focus. This approach mitigates proximity effects and out-of-plane hot spots. Previous limitations of low laser repetition rates and off-times between layers, where overcome with a high-power fs fiber laser operating at 500kHz in combination with an external pulse compressor and frequency doubling system.

Laser welding is a precise material-joining technique offering localised heating, minimal thermal damage, and contactless processing. For transparent polymers without an absorber layer, ultrafast pulses can trigger the non-linear phenomena needed for welding. This study optimises the scanning speed and fluence per pulse for welding polycarbonate using a 1.03 μm wavelength femtosecond laser. The cumulative fluence was calculated at the weld seam's centre and edge to determine the maximum and minimum energy per unit area, and the weld seam quality was assessed optically. Optimal results were achieved at scanning speeds of 10 and 20 mm/s with fluence per pulse of 0.38 – 0.72 J/cm2 and 0.65 – 1.14 J/cm2, respectively. Two damage regimes were identified: one caused by high cumulative fluence (283.4 J/cm2) at low speeds (5 mm/s), and the other by high fluence per pulse (1.50 J/cm2) at high speeds (30 mm/s). These findings provide insights into parameter selection for welding transparent polycarbonates.

Laser-based manufacturing enhances fiber bundle (FB) performance for biomedical imaging. FBs, widely used in endoscopy, suffer from pixelation, limited 2D imaging, and low photon efficiency. To address these challenges, we demonstrate a laser-based approach to improve FB functionality.

First, CO₂ laser-induced thermal expansion of fiber cores enhances photon efficiency without significant crosstalk. Second, femtosecond laser ablation and two-photon polymerization create holographic structures on the fiber facet, enabling dispersion correction. This transforms the FB into an ultrathin, flexible diffractive lens with a 500 µm focal distance, optimized for microendoscopy.

With a total diameter of 400 µm, the fiber lens integrates easily into raster scanning and wide-field microscopes, enabling unpixellated fluorescence imaging with 1 µm resolution. This advancement enables easy-to-use, low-cost, minimally invasive optical tools for diagnostics and research.