Innovative Mid-infrared high Power source for resonant ablation of Organic based photovoltaic devices

An EU FP7 collaborative project

An OverviewD.Wandt, Y. Hernandez, L. Leick, W. Richter, A. Grisard, G. van Steenberge, K. Walzer

Workshop WS06 Mid IR Photonics: Prospects and ChallengesECOC2012, September 16th, 2012, Amsterdam

• Specific Targeted Research Project (STREP)

• Seventh Framework Programme

• ICT-2009.3.7 Photonics

• 3-years: 1 September 2010 to 31 August 2013

• 6 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 Pumplaser

Isolator

Tm-fibre oscillator

Tm-fibre preamplifier 1st Tm-power amplifier

long-cavity

AOM pulse picking

MIR-conversion stage

Pumplaser

Process evaluationIntegration/Demonstrator

2st 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 …

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 (@6µm)

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

Thank you for your attention

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