Project: Ultrashort Pulse Lasers for Innovative Technology

The primary aim of this research project is the development of short pulse (pulse durations in range hundreds of femtoseconds to tens of picoseconds) amplification system capable to generate up to 125W (=100mJ, =1kHz) mean laser radiation power. We focus on developing new amplification schemes aiming to double the total amplification system efficiency while keeping small size. Another technological challenge is to manage thermal load to laser amplifiers elements. Here we plan to concentrate efforts in designing and realization of principally new amplification unit. As a part of the project, frequency conversion using ultra short pulse optical parametric generation and amplification will be performed. Applicability of powerful laser sources of tunable radiation for biotechnology and material processing will be studied. Scientifically, this project includes studies of thermal management of laser and nonlinear materials, depolarization and thermal lensing compensation. Studies on implementation of novel active laser materials, namely Yb doped fluorides, will be performed. Technical problems related to the control of complex amplification system ensuring safety of optical components and personnel have to be solved too._x000D__x000D_Application of advanced high-repetition-rate ultrafast laser sources, providing precise control over energy deposition on a target, creates unique (and still unexplored) opportunities for the material processing, medical treatment and basic research. At the end of 2007, the market of materials processing demanded for a new class of ultrashort-pulse laser systems with more than 10-20 times higher average power and productivity as compared to the existing ultrashort-pulse laser systems. _x000D_New Yb doped laser materials emitting around 1.06µm directly pumped by laser diodes and perfectly matched by generation wavelength, created unique possibility to design relatively simple, efficient and inexpensive ultrafast laser systems. In comparison with titanium doped sapphire ultrafast laser systems dominating basic research , medical therapeutic and technological markets, Yb and Nd ions based ultrafast systems pledge to be less complicated and easier scalable to high powers required by high yield production. Access to wavelength tunability in the mid IR range is very important for applications dealing with organic molecules, medical treatment, polymer processing. Today only free electron lasers (FEL) could provide short pulses with reasonable mean power in the range of 2-6 µm. However, this class of lasers is very complicated and expensive to be every day tool for manufacturing and medical treatment. In contrast powerful short pulses by means of nonlinear frequency conversion will provide mid IR tunability with reasonable efficiency for reasonable money. _x000D__x000D_Project oriented to three largest laser application markets: 1. Material processing; 2. Medical therapeutic; 3. Basic research. All of this markets have their specifics but application of ultrafast lasers brings a lot of advantages. Review of the laser market clearly demonstrated last year's tendencies ir growing demand on ultrafast lasers in all of above mentioned markets. For example, figures presented at Laser & Photonics Marketplace seminar on January 21, 2008, San Jose, California, show that ultrafast lasers sales were 27,8% of total sales for material processing, 40% for medical therapeutic applications and 58,7% for basic research. Annual growth from 3% to 7% is predicted in the year 2008. The total market targeted by UPLIT for this three areas is predicted to be 2.33 Billion $ in 2008._x000D__x000D_Material processing market benefits from extremely precise energy deposition on the target. To accelerate an application of ultra short pulse lasers in this field we need to boost the output power of the lasers by at least one order of magnitude (to hundreds of Watts) in comparison to state of the art systems. Polymers and another organic materials machining requires not only UV irradiation, easily obtainable today but , what is more complicated, also laser tunable in midIR. Though nonlinear power conversion efficiency is good for ultrafast lasers, we need to boost IR power if we want develop real technologies. The same situation holds in medical therapy. The only difference is demand of lasers tunable in 2-6 µm wavelength range, which corresponds to the absorption of organic molecules._x000D__x000D_The UPLIT Consortium, led by the short-pulse laser manufacturer Ekspla UAB and Photonics Institute of TU Vienna, known for its pioneering work on ultrafast lasers, will jointly pursue two alternative approaches to the outlined 100mJ/100W goal: based on direct ps pulse amplification in Nd-doped DPSSL and using a proprietary pulse time division/recombination scheme, as well as on emerging broadband Yb-doped crystal technology in a CPA configuration. Due to the complexity of technical challenges, the envisaged power/energy scaling will require a broad set of measures.

Acronym UPLIT (Reference Number: 4335)
Duration 01/07/2008 - 30/06/2011
Project Topic We aim to develop and commercialize schemes for =100 mJ (sub-) picosecond pulse laser amplification operating at unprecedented average power (=100 W) and repetition frequency (=1 kHz) levels for use in rapid materials processing applications (ablation, deposition, bulk restructuring, etc.).
Project Results
(after finalisation)
1. Constructed femtosecond fiber optic master oscillator;_x000D_2. Constructed OPCPA frontend based on fiber chirped pulse amplifier pumped CEP stable OPA; _x000D_3. Constructed cryogenically cooled Yb:CaF2 regenerative amplifier delivering up to 10mJ pulses with pulse duration less than 200fs at 1 kHz repetition rate;_x000D_4. Built OPCPA system producing 80 fs pulses in MidIR (3.9mkm) with energy up to 7mJ;_x000D_5. Built high energy amplifier system for OPCPA pumping running at 1kHz repetition rate and providing 100mJ pulse energy;_x000D_6. Developed high averaged power (P>15W) regenerative amplifier generating stable picosecond pulses which can be used for laser technology;_x000D_7. Developed source of 1mJ picosecond pulses operating at 4kHz repetition rate, which can be used for seeding of laser amplifiers or directly for laser technology;_x000D_8. Developed prototype of 1MHz repetion rate picosecond cavity dumped oscillator ;_x000D_9. Tested applicability of multidisc-configurated active elements for laser amplifiers.
Network Eurostars
Call Eurostars Cut-Off 1

Project partner

Number Name Role Country
2 UAB Ekspla Coordinator Lithuania
2 Photonics Institute, Vienna University of Technology Partner Austria