Interview with Prof. Henryk Fiedorowicz
Interview with Prof. Henryk Fiedorowicz
from Military University of Technology in Poland
1. Dear prof. Fiedorowicz, WAT has ordered from PREVAC the implementation of the vacuum process chamber for a vacuum device for surface modification of polymers based on laser-plasma EUV source. Can you tell us something about configuration of your equipment, its possibilities, technical data?
The vacuum chamber ordered from PREVAC is a basic element of the laser plasma source of extreme ultraviolet (EUV) dedicated for modification of polymer surfaces. EUV photons break the polymer chains and characteristic nano- and microstructures are created onto the polymer surface that change its physical and chemical performances. The source has been developed under the EUREKA program in collaboration with our partners from Austria and Czech Republic. The use of EUV for modification of polymer surfaces for application in biomedical engineering was proposed by our Austrian partner from the Institute of Applied Physics at Linz University. EUV light is generated from a hot plasma produced in result of irradiation of a gas puff target with nanosecond laser pulses from a Nd:YAG laser (EKSPLA). The source emits EUV radiation in the wavelength range from about 5nm to 50 nm with a strong maximum near 10nm in the pulses of 4ns time duration at 10Hz repetition rate.
2. Chamber delivered by PREVAC provides different pressure on each level. What is the destination of such configuration of chamber? How was it able to achieve different pressures keeping free path for the laser? how does this solution work?
The source chamber is composed from three separate sections. In the first section the valve system to form gas puff targets and the laser beam focusing system are mounted. This section is evacuated with an oil-free rotary pump. In the second section, that is separated from the first section by a small diaphragm, an ellipsoidal mirror to collect EUV radiation emitted from the laser-irradiated gas puff target and focus onto a sample is placed. This section is evacuated using the turbo molecular pump. The third section is also separated by a small diaphragm from the second section and pumped with the turbo molecular pump. Thus, a sample mounted in this section with the use x-y-z translation stages can be irradiated with EUV in high-vacuum environment.
3. You modify polymers' surface using PREVAC's chamber - can you tell us the results you got?
The EUV source with the PREVAC's chamber has been used in many experiments on modification polymer surfaces. In the studies on cultivation of biological cells on the modified surfaces performed in Austria it was demonstrated that the cells show good adhesion and align along oriented wall- and ripple-type microstructures on PET surfaces produced by the EUV irradiation. Moreover, significant chemical changes due to the EUV irradiation were shown. Control experiments with the pulsed UV-laser irradiation also resulted in formation of oriented wall-type microstructures on PET surfaces but in a much smaller parameter range than with the EUV irradiation. CHO cells seeded on UV-laser-induced structures show less pronounced alignment.
4. The Institute of Optoelectronics already work on five PREVAC's systems. You also chose PREVAC as cooperator creating EUV? How could you describe the cooperation with PREVAC in general?
In our laboratory we are using a few vacuum chambers that are used in various experiments on interaction of laser radiation with matter. These chambers have been designed and developed in close cooperation with PREVAC team of engineers and technicians. We found this cooperation highly successful. It was possible to build the interaction chamber that fulfilled our specific requirements.
5. We can read about your achievements in nanomedicine within the project "EUREKA" - can you describe what was the goal of this project?
The goal of the EUREKA project was to develop a new technology and instrumentation for modification of polymer surfaces with EUV light for application in biomedical engineering. Surface modification is caused by formation of nanostructures on the polymer surface that change its biocompatibility. A precise control of the biocompatibility of polymer surfaces is one of the main problem to be solved in biomedical engineering. Solving this problem will make possible to replace various organs with artificial parts made from polymers.
6. We heard that WAT laboratory will be a part of CEZAMAT project - can you tell us about it?
The Laser-Matter Interaction laboratory becomes a part of the Laser Nanotechnology laboratory that was formed as the satellite laboratory in CEZAMAT project. The laboratory at MUT will be specialized in the research on the use of lasers in the development of new materials and technologies which are planned at CEZAMAT. Because of participation in CEZAMAT project our laboratory was able to upgrade the femtosecond Ti:sapphire system and acquire a new diagnostic instrument to study physical processes that take place during the interaction of high-intensity laser pulses with matter. The new instrument consists of the vacuum interaction chamber from PREVAC and the quadrupole mass spectrometer (QMS). It will be used in the research on ablation of polymers irradiated with EUV pulses.
- EUREKA PROJECT - MODIFICATION OF POLYMER FOILS WITH EUV (EXTREME-ULTRAVIOLET) RADIATION FOR APPLICATIONS IN BIOMEDICAL TECHNOLOGY
- LASER PLASMA EUV SOURCE FOR MICRO AND NANOPROCESSING OF POLYMERS
Read fallowing articles about EUV, imaging using EUV, analysis of gas shields using EUV etc.: