Innovative Mid-infrared high Power source for resonant ablation of Organic based photovoltaic devices An EU FP7 collaborative project An Overview D.Wandt, Y. Hernandez, L. Leick, W. Richter, A. Grisard, G. van Steenberge, K. Walzer Workshop WS06 Mid IR Photonics: Prospects and Challenges ECOC2012, September 16 th, 2012, Amsterdam

Specific Targeted Research Project (STREP) Seventh Framework Programme ICT Photonics 3-years: 1 September 2010 to 31 August work packages, 37 deliverables and 5 milestones Two global players, two SME‘s, three research institutes Facts and figures

LZH (Germany, Coordinator) Multitel (Belgium) NKTP (Denmark) Batop (Germany) TRT (France) IMEC (Belgium) Heliatek (Germany) The consortium

Laser Processing of organic photovoltaic devices without UV-VIS-NIR produced photochemical processes which converts photon energy into desired material modification minimal leakage of energy into heat, defect formation need to deliver laser energy before heat diffusion processes occur  IR-resonances of organic molecules  corresponding short pulse lasers Resonant infrared ablation with a wavelength tunable laser system The idea behind …

Short-pulse mid-infrared multi-stage Laser system fixed wavelength/tunable Tm-fibre oscillator as seed source around 2 µm high power Tm-fibre amplifier chain as front-end OPG/OPA based nonlinear wavelength conversion stage with single/multi grating orientation patterned GaAs  wavelength range: from 2.5 µm to 8 µm  pulse duration: ~ 250 ps, as defined  repetition rate: < 1 MHz  energy per pulse: 10 µJ at 6 µm The laser source

Tunable short pulse radiation systems Mode-locked Tm fibre oscillators (LZH) Tm fibre amplifiers (MULTITEL) GaAs nonlinear conversion stage (Thales) Integration, Opto-Mechanical Engineering components (all) subsystems (all) Multi-functional Components Saturable absorbers (Batop) Fibre couplers (LZH) PCF based devices (NKTP) nonlinear crystals (Thales) Resonant Infrared Ablation sample preparation (HEL, IMEC) process evaluation set-up (IMEC) ablation tests (IMEC, HEL, LZH, Multitel, Thales) Needs … and Responsibilities

Needs … and possible solutions Pumplaser Isolator Pumplaser Isolator Tm-fibre oscillator Tm-fibre preamplifier 1 st Tm-power amplifier long-cavity AOM pulse picking MIR-conversion stage Pumplaser Process evaluationIntegration/Demon strator 2 st Tm-power amplifier

Current status … Ultrafast Tm-fiber oscillator (WP2)  All-fiber set-up with polarisation maintaining fibers  Mode-locking by saturable absorber mirror (SAM)  Center wavelength 1980 nm, fixed by FBG  0.4 nm spectral width  10 ps pulse duration  20 MHz repetition rate  10 mW average output power

Current status … Ultrafast Tm-fiber oscillator XXL  Spectral shaping with passive PM 1950 fiber  Pulse stretching with chirped FBG  Power amplification with PM-Thulium fiber  Pulse picking with AOM 1nm spectral width 250 ps pulse duration 400 mW average power Single-shot to fundamental rep-rate

Current status …

Ultrafast Tm-fiber power amplifier (WP3)  3.2 Watt average output power  250 kHz repetition rate  12.8 µJ output energy  250 ps pulse duration

Under development … Nonlinear conversion stage (WP4)  Orientation patterned GaAs crystals in OPA/OPG configuration  2.5 µm to 8 µm wavelength range, tunable by seed, crystal temperature, multiple period, etc.  10µJ per pulse

Under development … Validation of the mid-infrared laser source for structuring organic photovoltaic material stacks (WP5)  IR absorption measurements/characterisation  Preparation of the process evaluation set-up  Integration of the fixed-wavelength laser source  Single layer ablation tests  Integration of the tunable laser source  Multi-layer ablation tests

Final steps … Demonstration of the overall functionality of the MIR laser source (WP6)  Mechanical and optical parameters  Integration/Compatibility with practical industrial applications

Resonant Infrared ablation (RIA) Proof of principle, scribing tests, using  Polycarbonate (PC)  On resonance 3.39 µm  Off-resonance 3.03 µm

RIA... the latest news

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