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Projects / Programmes source: ARIS

Ultrashort pulses on demand

Research activity

Code Science Field Subfield
2.10.00  Engineering sciences and technologies  Manufacturing technologies and systems   

Code Science Field
T165  Technological sciences  Laser technology 

Code Science Field
2.03  Engineering and Technology  Mechanical engineering 
Keywords
Laser technology, Fiber lasers, Pulses on demand, Ultrafast laser pulses characterisation
Evaluation (rules)
source: COBISS
Researchers (12)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  32091  PhD Vid Agrež  Technology driven physics  Researcher  2018 - 2021  86 
2.  38760  PhD Luka Černe  Manufacturing technologies and systems  Researcher  2018 - 2021  19 
3.  32339  PhD Blaž Kavčič  Physics  Researcher  2018 - 2020  33 
4.  24380  PhD Blaž Kmetec  Technology driven physics  Researcher  2020 - 2021 
5.  52343  Jernej Jan Kočica  Manufacturing technologies and systems  Technical associate  2019 - 2021  20 
6.  37953  PhD Jaka Mur  Manufacturing technologies and systems  Researcher  2018 - 2021  52 
7.  32338  PhD Vid Novak  Computer intensive methods and applications  Researcher  2018 - 2019  13 
8.  35427  PhD Jaka Petelin  Physics  Researcher  2018 - 2021  54 
9.  15646  PhD Rok Petkovšek  Manufacturing technologies and systems  Head  2018 - 2021  273 
10.  12752  PhD Boštjan Podobnik  Physics  Researcher  2018 - 2021  62 
11.  35440  Marko Šajn  Manufacturing technologies and systems  Technical associate  2018 - 2020 
12.  39197  PhD Peter Šušnjar  Technology driven physics  Junior researcher  2018 - 2020  12 
Organisations (2)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0782  University of Ljubljana, Faculty of Mechanical Engineering  Ljubljana  1627031  29,212 
2.  7741  LPKF LASER & ELECTRONICS d.o.o. (Slovene)  Naklo  5711096  314 
Abstract
Today’s industry is increasing its investment in to the research of laser micro-processing, where precision and high speed of processing are required. These requirements are directly correlated to two key components of laser processing systems: the laser source and the scanning system. Above all the scanning system must provide high speed. In addition to high precision, the laser source must also meet the requirement for high speed and thus flexibility in terms of efficient synchronization with the scanning system. The latest and more importantly the now emerging generations of polygon and resonance scanners already provide exceptional scanning speeds. For example in the case of polygon scanners, the beam scanning speed along the sample can reach several km/s. The problem arises because they operate at a constant speed, so that with standard laser pulse sources operating at a constant repetition rate, we can only construct structures with equal spacing on the sample. Similar problem arises in the case of resonant scanners which are demanding for synchronization because of nonlinear response (resonant response - sinusoidal oscillation) of the scanner. The solution in both cases is the use of laser source capable of producing pulses on demand with pulse duration in the ps/fs range. The need for high scanning speed and high precision of the laser beam on the subtract define the needed time resolution of the pulse position on demand; at scanner speed of 2 km/s and required precision of 5-10 µm a laser pulse with time resolution of under 5 ns is required which is not achievable with the modern laser systems The goal of the project are R&D of the laser systems with ultra-short laser pulses (ps/fs range) which adhere to requirements stated above. The proposed concept is based on direct driving of seed source. In contrast to the established mode locked sources we will use the DFB type laser diodes, which allow for such driving operation and thus totally arbitrary generation of pulses on demand. For achieving this, three key innovative and breakthrough solutions will be introduced: First a spectral broadening of the seed pulses from the laser diode by means of the otherwise undesired effect of self-induced phase modulation (SPM). With the use of SLM the pulse will be transformed in such a way that it will be suitable for amplification in the CPA MOPA system based on active optical fibers. Second innovative approach to realization of the project goals will be the use of tapered fibers with which an alternative to usually used complex photonic crystal fibers PCF will be achieved. The tapered fibers applied to the CPA systems will served for adequate spectral broadening of the seed diode, which is the key for working of CPA amplifiers. Thirdly: to optimize the spectral transformation and thus the entire proposed laser system, we will research and develop an innovative and original, highly sensitive system for the analysis of ultra-short laser pulses based on the FROG method. Research on this work package will be carried out in close cooperation with the group led by prof. dr. Rick Trebino. Prof. Trebino is a worldwide authority in this field since he is the inventor of several methods for the characterization of ultra-fast laser pulses. The system for characterization of pulses is also one of the key results of the project. With his help we will be able to analyze the transformed and broadened spectrum obtained from different types of narrowed fibers, which will help to compensate the non-linear phase using the SLM modulator. With the proposed laser system, it will be possible to take full advantage of the potential of fast new-generation scanning systems - full and arbitrary synchronization between the pulsed laser source and the scanning system will be possible. In the future, such systems will open up completely new areas of potential applications of high-precision and ultra-fast laser micro-processing and related new
Significance for science
The project is designed as an application project, combining and upgrading knowledge for the characterization and transformation of the laser output of the pulsed excitation diode. Such an innovative solution will allow the use of the CPA system to achieve high peak power of the laser system. The following novelties are highlighted as crucial for the development of science and the profession: The generation of ultra-high-speed pulses on demand of the machining system, utilizing the full potential of the scanning system and enabling a completely new field of potential applications in highly precise and ultra-fast laser micro-processing, as well as related new research directions. The aforementioned spectral transformation of the excitation laser pulse via spectral broadening using self-induced phase modulation (SPM) phenomenon and the correction of the nonlinear contribution for the following effective pulse compression opens up a new way of application and also the further development of non-linear fiber optics. An original approach to the use of tapered fibers (having very small diameter) to increase the nonlinearity resulting in spectral broadening. This will replace the complex PCF fibers that are otherwise used in such cases. The use of tapered optical fibers in CPA systems is the original result of the project, which will allow us to start researching new types of CPA systems. Development and production of an original, highly sensitive system for the analysis of ultra-short laser pulses based on the FROG method, which is also one of the key results of the project. The development of this method will contribute to scientific knowledge, as much attention will be paid to the knowledge and control of the evolution of the spectrum and the shape of the pulses inside the laser system.   The project partner FS-FOLAS will actively take care of the dissemination of new results and findings, in the framework of work package 6. Dissemination will be provided by scientific articles, attendance at scientific conferences and hosting of researchers from related work areas from EU Member States and more widely. In particular, we are expecting great interest in the results of the project, as the group had two invited lectures in the last year in the field of laser pulse manipulation in conection with processing systems.
Significance for the country
The results of the project have the potential to strengthen the position of the industrial partner in the market of laser machining systems. The proposed research will use new and innovative principles for the generation of picosecond pulses, suitable for complex manufacturing processes at very high processing speeds, the direction in which the market for laser processing technologies is developing. The advantage of the proposed solutions is their openness for further development and the inclusion of potential products in the company's commercial scheme. Research on tapered fibers as elements for the spectral broadening of picosecond pulses suitable for amplification in iterbium amplifiers have the potential to circumvent the patent protected scope of the use of standard approaches based on PCF fibers and pave the way for the industrial partner to enter the CPA systems market. Thus, the company LPKF will acquire new technological solutions for the realization of fiber laser systems. This is is of great importance for the company, because of the modernization of the market of laser sources for processing systems, the solid-state lasers are being replaced with fiber lasers. In addition to technological solutions, the company will further strengthen its contact with the academic sphere and establish stronger contacts with students who will also be active in the project in the form of master's and master's thesis.
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