Matthias Feinaeugle

Micron-scale copper wires printed using femtosecond laser-induced forward transfer with automated donor replenishment

We demonstrate the use of laser-induced forward transfer (LIFT) in combination with a novel donor replenishment scheme to print continuous copper wires. Wires of mm length, a few microns wide and submicron in height have been printed using a 800 nm, 1 kHz repetition rate, 150 fs pulsed laser. A 120 nm thick copper donor was used along with laser pulse energy densities of 0.16-0.21 J cm−2 to print overlapping few-micron sized pads to form the millimeter long wires. The wires have a measured resistivity of 17 ± 4 times that of bulk copper.

Fabrication of a thermoelectric generator on a polymer-coated substrate via laser-induced forward transfer of chalcogenide thin films

We have demonstrated the fabrication of a thermoelectric energy harvesting device via laser-induced forward transfer of intact solid thin films. Thermoelectric chalcogenide materials, namely bismuth telluride (Bi2Te3), bismuth selenide (Bi2Se3) and bismuth antimony telluride (Bi0:5Sb1:5Te3), were sequentially printed using a nanosecond excimer laser onto an elastomeric polydimethylsiloxane-coated glass substrate to form thermocouples connected in series creating a thermoelectric generator. The resulting generator Seebeck coefficient and series resistance per leg pair were measured to be 0.17 mV K-1 and 10 kilohms respectively. It was shown that laser-induced forward transfer allows device fabrication from inorganic semiconductor compounds on inexpensive elastic polymer substrates and demonstrates the ability to print materials with pre-defined thermoelectric properties. This allows the rapid manufacturing of a complete thermoelectric device on mm2-areas with µm-scale precision, without the need of further lithographic steps.

Single-pulse multiphoton polymerization of complex structures using a digital multimirror device

We present a rapid technique for the patterning of complex structures with ~2µm resolution via multiphoton polymerization, through use of a single ultrashort pulse in combination with the spatial intensity modulation possible from a digital multimirror device. Sub-micron features have been achieved through the use of ten consecutive pulses.

Sub-micron-scale femtosecond laser ablation using a digital micromirror device

Commercial digital multimirror devices offer a cheap and effective alternative to more expensive spatial light modulators for ablation via beam shaping. Here we present femtosecond laser ablation using the digital multimirror device from an Acer C20 Pico Digital Light Projector and show ablation of complex features with feature sizes ranging from sub-wavelength (400 nm) up to ~30 µm. Simulations are presented that have been used to optimize and understand the experimentally observed resolution.

Waveguide mode filters fabricated using laser-induced forward transfer

Titanium in-diffused lithium niobate index-tapered waveguides have been fabricated using laser-induced forward transfer technique for mode-filtering applications. Details of their fabrication, losses and transmission characterization are presented.

Laser-Induced Forward Transfer-printing of focused ion beam pre-machined crystalline magneto-optic yttrium iron garnet micro-discs.

We present femtosecond laser-induced forward transfer of focused ion beam pre-machined discs of crystalline magneto-optic yttrium iron garnet (YIG) films. Debris-free circular micro-discs with smooth edges and surface uniformity have been successfully printed. The crystalline nature of the printed micro-discs has not been altered by the LIFT printing process, as was confirmed via micro-Raman measurements.

Laser ablation via programmable image projection for submicron dimension machining in diamond

A digital micromirror device is used as an intensity spatial light modulator, in conjunction with a femtosecond laser, for programmable image-projection-based laser ablation of polycrystalline diamond. Results show the machining of complex structures on the diamond surface, where individual structures have submicron features, covering a total area of 10 × 10 μm and fabricated using ten laser pulses. This dynamic image-based machining technique may offer speed advantages over serial-writing procedures, whilst still producing wavelength-scale feature sizes.

Deposition of elements for a thermoelectric generator via laser-induced forward transfer

Films of thermoelectric bismuth selenide and bismuth telluride have been transferred by laser-induced forward transfer onto glass and polymer substrates. Influence of transfer on thermoelectric properties and morphology of the material was compared.

Digital micromirror device based adaptive optics approach for enhanced micro-machining fidelity (Conference Presentation)

Outline - Past work and challenges in DMD projection-based laser manufacturing - DMD mask shifting - Taking advantage of limited bandwidth - Custom substrates, including cell growth assays - Conclusions Will go through some of our past work, along with challenges we’ve faced. Will show how a combination of mask repositioning on the DMD and exploiting limited bandwidth can overcome some of these problems. Will show some of the work we’re doing towards cell growth assays. Developing laser manufacturing techniques, with UK industrial partners, for high-precision, high-speed, flexible etc fabrication - applications in sensing, bio-medicine, metamaterials, etc etc etc. DMDs offer many advantages for laser machining, which have yet to be established in industry. Not just beam shaping, but other more advanced techniques, which the group at Southampton are pioneering, and I will talk about some of these today.

Data supporting journal publication 'Time-resolved imaging of flyer dynamics for femtosecond laser -induced backward transfer of solid polymer thin films'

We have studied the transfer regimes and dynamics of polymer flyers from laser-induced backward transfer (LIBT) via time-resolved shadowgraphy. Database contains images and schematics of the used setup to collect this data.Data collection: Time-resolved shadowgraphy with CCD camera between 18 April 2016 and 23 April 2016.