Laser Applications Department
Optical measurement technique
List of publications (since 1994)
One of the main activities of this group is the development of PC controlled air- and liquid-borne particle counters. In these instruments the determination of the size distribution and concentration of the particles is based on laser light scattering. A new airborne particle counter with a modular measuring head with increased sensitivity, better signal/noise ratio and improved signal evaluation system was developed last year. The APC-01-02 particle counter can also be used with a built-in PC and has its own display. The lower size limit of this device is 0.2 micron, which can be measured in a wide concentration range – 10 – 3 000 000 particles/litre.
A portable battery operated note-book PC-controlled airborne particle counter PAPC-03-2 was developed for determination of the size distribution and concentration of sub-micron- and micron-range particles in air and in gases at low and high concentrations (see picture).
A portable liquid-borne particle counter LQB-1-200 has also been developed.
A new forward-backward scattering laser particle studying method was developed for sizing, counting and estimation of the complex refractive index of aerosol particles in the sub-micron and micron size-range in collaboration with the University of Vienna. For modelling of this method a new algorithm is proposed, and a new software was created for data evaluation.
A measuring head, based on the above mentioned method is constructed and calibrated for various particles. The results show a number of benefits of the new method in comparison with the previous airborne counting methods.
New results were obtained in using the previously developed high resolution sampling laser interferometer. The mechanical transient phenomena studied by this device provide the determination and analysis of the displacement and vibration parameters of the mechanical system with high resolution and precision.
Work in the field of integrated optical sensor for the revelation of laser radiation, its presence and direction of propagation has been finished.
Theoretical work has been done for the study of the statistics of scattered intensities. Findings of the computational model were proved by experiments. Technical criteria of sensors have been specified.
The measuring system for the standardles determination of the quantum efficiency of the photon counting detectors using entangled photon pairs was developed. This method is based on the generation of non-classical quadrature squeezed light by non-collinear parametric down-conversion.
Further information:
Aladár Czitrovszky, E-mail: 
Péter Jani, E-mail: 
Amorphous thin layers
List of publications (since 1994)
This group has rich experiences in the field of preparation and investigation of amorphous thin films. The investigations have been focused to look for connections between structure and such macroscopical properties, like electrical transport, optical properties, photo-conductivity and photoluminescence. Most of the equipment, which are needed to the preparation and investigation of the samples are operated by the group. In the last few years the group have been dealing with hydrogenated amorphous carbon (a-C:H) films, and mostly with those, showing diamond-like properties. These films are prepared by radio-frequency (rf) glow discharge from different organic materials (methane, benzene and others) by controlling the preparation conditions, like the gas composition, flow rate, gas pressure, and rf power. The physical properties of the films prepared in this way can be varied in a broad range.
Photoluminescence (PL) investigations of a-C:H thin layers prepared either from methane or benzene source gases were performed with aim to specify the whole range of light emitted by these samples what contributes considerably to a further understanding of the fine structure of the electron density of states and the details of the radiative recombination in this material. We have shown composite feature of PL spectra, consisting of numerou characteristic bands, some of these appear already in the visible range of excitation, the others can be excited by UV light only. Three peaks with maximum position in the range of 4.34 - 4.50 eV, 3.93 - 4.01 eV and 3.64 - 3.70 eV are in the ultraviolet region. Additional peaks appear in the region of 3.17-3.22 eV and 2.85 - 2.92 eV beside the well-known broad PL band with maximum in the 2.1 - 2.33 eV range. The relative intensity of new bands vary on deposition conditions. Our results measured on numerous samples strongly suggest the existence of some type of intrinsic radiative centers.
The growth process of the carbon film was followed by IR spectra, by investigating film prepared under different deposition conditions. Surprisingly good spectral resolution could be achieved on samples deposited from benzene as source gas at relatively high pressure and low voltage conditions. Because the C-H bond-stretching region contains intensive aromatic components, we draw the conclusion, that the benzene ring structure can survive the deposition condition in the plasma, the ionization could eliminate hydrogen atom from the molecule. The structure will probably have a high active surface, what might have practical application possibilities.
New Raman spectrometer was installed this year in our group. The access to two different laser excitation makes dispersion measurements also possible.
Optical strength of a-C:H thin layers was investigated under influence of UV laser pulses in the ns and fs region on different laser wavelength. The possible utilization of these films in laser and microelectronic technology motivates these studies. The damaged area was found to depend linearly on the laser fluence in a narrow region around the damage threshold tested by rising number of pulses and fluence. The 2 - 3 times higher optical damage strength for fs pulses on both wavelengths used, can be explained by the different weights of electronic and thermal processes in the case of strongly different pulse lengths. Accumulative effects for multiple pulse impact were detected which was more clearly developed for UV region. The incubation process was the shortest for the long pulse length.
Further information:
Margit Koós, E-mail: 
Optical Thin Films
List of publications (since 1994)
The thin film group is the only native research group of optical coatings used in ultraviolet, visible and infrared lasers in Hungary. The custom designed optical interference coatings are synthetized and analyzed with a self-written computer software and are deposited by reactive, electron-beam vacuum evaporation technology. The most important realized optical coatings are the following: multilayer resonator mirrors and antireflection coatings of noble gas-, metal-vapor-, solid state-, excimer- and dye lasers; front-polarizers, band-edge filters, analytical interference filters, transparent and electrically conducting coatings (ITO), surface guided-wave layers.
Further Information:
Kárpát Ferencz, E-Mail: 
Ultrafast Laser Technique Laboratory
List of publications (since 1994)
During the past few years, the group achieved outstanding scientific and technological results in the area of ultrashort (femtosecond) pulse lasers by the invention (R. Szipőcs, 1993) and technological development of the so called "chirped" dispersive dielectric laser mirrors. As an example, it is worth mentioning that the shortest laser pulses ever achieved (4.5 fs) are generated by a Ti:sapphire laser system utilizing ultrabroadband chirped mirrors for dispersion control at the University of Groningen (the Netherlands).
In 1998, a new laboratory for ultrafast laser technique and laser spectroscopy was founded. Besides the scientific and technical expertise of the staff, the laboratory comprises a 10 W Ar-ion laser (Spectra-Physics), a tunable cw and femtosecond pulse Ti:sapphire laser (R&D Ultrafast Lasers Ltd.), a synchronously pumped, femtosecond pulse optical parametric oscillator (NT&C) and a high resolution double monochromator (CVI). The unique feature of the two femtosecond pulse systems is that they utilize chirped mirror technology for broadband feedback and intracavity dispersion control.
Current scientific interest of the laboratory includes:
- Development and testing of > 1 W average output power, sub-10-fs pulse, mirror dispersion controlled Ti:sapphire lasersMode-locking techniques including passive and active mode-locking techniques
- Nonlinear optics including second harmonic generation (SHG), parametric wave generation and phase conjugation with femtosecond pulses
- Femtosecond pulse characterization by autocorrelation (AC) measurement or frequency resolved optical gating (FROG) method
- Development of chirped dispersive dielectric mirrors for different femtosecond pulse laser systems
- Phase dispersion measurement on laser mirrors and optical materials such as laser crystals by spectrally resolved white light interferometry
- Raman spectroscopy by the use of our tunable, cw Ti:sapphire laser
- Investigation of surface plasmon dynamics by femtosecond pump-probe technique
Further information:
Róbert Szipőcs, E-mail: 
Relevant publications
A. Czitrovszky, P.Jani. New design for a light scattering airborne particle counter and its application, Optical Engineering 32, 2557 - 2562 (1993).
A. Czitrovszky, P. Jani, Application examples of APC-03-2 and APC-03-2A; Airborne Particle counters in a highly contaminated environment, Journal of Aerosol Science 26, 793-794 (1995).
A. Czitrovszky: Development of instruments and methods for aerosol measurements in the Research Institute for Solid State Physics and Optics, J. of Aerosol Science, 32, 1029-1030 (2001)
A. Nagy, W.W. Szymanski*, A. Czitrovszky, C. Schindler*, P. Jani: Modelling of a dual wavelength optical system for the estimation of the refractive index of aerosol particles in APC, J. of Aerosol Science, 32, 1028-1029 (2001)
A. Nagy, W.W. Szymanski*, A. Czitrovszky, P. Jani: Modelling of a new optical aerosol particle analyser for the simultaneous measurement of size, complex refractive index and density, J. of Aerosol Science, 32, S83-S86 (2001)
P. Jani, Z. Lipp. A. Nagy, A. Czitrovszky: Propagation delay statistics of scattered intensities, J. of Aerosol Science, 32, S87-S88 (2001)
P. Jani, A. Nagy, Z. Lipp, A. Czitrovszky: Simultaneous velocity and size measurement of-particles in photon correlation experiments: SPIE V. 4416 pp. 236-240. 2001.
A. Nagy, W.W. Szymanski, A. Czitrovszky, P. Jani: Modelling of a new optical aerosol particle analyzer for the simultaneous measurement of size, complex refractive index and density, J. of Aerosol Science V. 32. p. 83-85. 2001.
P. Jani, Z. Lipp, A. Nagy, A. Czitrovszky: Propagation delay statistics of scattered intensities, J. of Aerosol Science V. 32. p. 87-89. 2001.
P. Jani, M. Koniorczyk, A. Nagy, A. Czitrovszky: Probability distribution of scattered intensities, J. of Aerosol Science V. 32. p. 563-565. 2001.
P. Jani, M. Koniorczyk, A. Nagy, Z.Lipp, B. Bartal, A. László, A. Czitrovszky: Probability distribution of scattered intensities, (Paper in print) J. of Aerosol Science, 2001.
P. Apai, S. Lakó, R. Szipőcs, M.B. Danailov*: Broad-band photorefractive phase conjugation in a dispersive scheme. Laser Physics 10, 444-448 (2000).
R. Szipőcs*, A. Euteneuer*, E. Finger*, M. Hofmann*, A. Kőházi-Kis*: Multi-color, mode-locked Ti:sapphire laser with zero pulse jitter. Laser Physics 10, 454-457 (2000).
R. Szipőcs, A. Kőházi-Kis*, S. Lakó, P. Apai, A. P. Kovács*, G. DeBell*, L. Mott*, A. W. Louderback*, A.V. Tikhonravov*, M.K. Trubetskov*: Negative Dispersion Mirrors for Dispersion Control in Femtosecond Lasers: Chirped Dielectric Mirrors and Multi-cavity Gires-Tournois Interferometers. Appl. Phys. B70, S51-S57 (2000).
R. Szipőcs, A. Kőházi-Kis*, P. Apai, E. Finger*, A. Euteneuer*, M. Hofmann*: Spectral filtering of femtosecond laser pulses by interfernce filters. Appl. Phys. B70, S63-S66 (2000).
I. Pócsik, M. Koós and O. Berkesi: The Consequences of Decreasing Particle Size on The Raman Spectroscopy of Carbons In: Nanostructured Carbon for Advanced Applications, Ed. by G. Benedek, P. Milani and V.G. Ralchenko; NATO Science Series II. Vol. 24., Kluwer Academic Publishers, New York 2001. pp. 169-176.
I. Pócsik and M. Koós: Consequences of Size-Effect and Spectral Inhomogenity on Raman and Photoluminescence Spectra of a-C:H. Diamond and Related Materials Vol. 10, No. 2, PP. 161-167, 2001.
O. Krafcsik, G. Vida, I. Pocsik, K.V. Josepovits, P. Deak: Carbon diffusion through SiO2 from a hydrogenated amorphous carbon layer and accumulation at the SiO2/Si interface
Japanese Journal of Applied Physics, Part 1-Regular Papers Short Notes & Review Papers 40 (4A): 2197-2200 APR 2001.
M. Koós, M. Veres, M. Füle and I. Pócsik: Ultraviolet photoluminescence and its relation to atomic bonding properties of hydrogenated amorphous carbon. Diamond and Related Materials, Accepted for publication, 2001.
G. Cerullo*, M. Nisoli*, S. Stagira*, S. De Silvestri*, G. Tempea*, F. Krausz*, K. Ferencz: Mirror-dispersion-controlled OPA: a compact tool for sub-10-fs spectroscopy in the visible. Applied Physics B, Lasers and Optics B70, 253-259 (2000)
Conference proceedings
A. Czitrovszky, A. Nagy, P. Jani, K. Bodnár, Á. Illés: On-line aerosol measurement in the Codex_B4C test, "Nuclear Fission" Operational safty of existing installations, IPSN-DRS /SEMAR 01/75 SAM-COLOSS-M008, pp. 35-40, Budapest, 3-4 July 2001.
M. Koós, M. Füle, M. Veres, S. Tóth and I. Pócsik: Composite Character of the Photoluminescence In Hydrogenated Amorphous Carbon Films, 19th International Conference on Amorphous and Microcrystalline Semiconductors, 27-31 August 2001, Nice, France
L. Nánai, M. Füle, K. Bali, M. Veres, M. Koós and I. Pócsik: Optical Strength in UV Region of Amorphous Carbon, 12th European Conference on Diamond, Diamond-Like Materials, Carbon Nanotubes, Nitrides & Silicon Carbide, 2-7 September 2001, Budapest, Hungary.
M. Veres, M. Koós and I. Pócsik: IR Study of the Formation Process of Hydrogenated Amorphous Carbon Film, 12th European Conference on Diamond, Diamond-Like Materials, Carbon Nanotubes, Nitrides & Silicon Carbide, 2-7 September 2001, Budapest, Hungary
M. Koós, M. Füle, M. Veres, S. Tóth and I. Pócsik: Multi Band Structure Of Amorphous Carbon Luminescence, 12th European Conference on Diamond, Diamond-Like Materials, Carbon Nanotubes, Nitrides & Silicon Carbide, 2-7 September 2001, Budapest, Hungary
S. Lakó, P. Apai, R. Szipőcs, and I. Pócsik, Ablation Features of Gold and Hydrogenated Amorphous Carbon Films Mashined with Femptosecond Pulses of s Ti:sapphire Laser, XIInd Conference on Ultrafast Processes in Spectroscopy, Oct. 28 Nov. 1, Florence, Italy.
S. Lakó, P. Apai, R. Szipőcs: High Efficiency Second Harmonic Generation of Femtosecond Laser Pulses in Dispersion Compensated Ring Cavity. In: Proc. CLEO-Europe '00 Conference, Nice, France, Paper CThE 0013 (2000).
R. Szipőcs, S. Lakó, P. Apai, J. Seres*: Generation of 10 fs laser pulses using a compact 100 fs laser oscillator, optical fiber and dispersion compensation. In: "Kvantumelektronika 2000", Proc. of the 4th National Symposium on Quantum Electronics (3 November, 2000, Budapest), Ed. S. Varró (SZFKI, Budapest 2000), p.14 (in Hungarian)
J. Seres*, R. Szipőcs, S. Lakó, P. Apai, J. Hebling*: Modelling the propagation of 1 nJ, femtosecond pulses in microstructure optical fiber in the anomalous dispersion regime. In: "Kvantumelektronika 2000", Proc. of the 4th National Symposium on Quantum Electronics (3 November, 2000, Budapest), Ed. S. Varró (SZFKI, Budapest 2000), P12 (in Hungarian)
S. Lakó, P. Apai, R. Szipőcs: Second harminic generation of femtosecond laser pulses in dispersion compensated ring cavity. In: "Kvantumelektronika 2000", Proc. of the 4th National Symposium on Quantum Electronics (3 November, 2000, Budapest), Ed. S. Varró (SZFKI, Budapest 2000), P15 (in Hungarian)
P. Apai, N. Nubhash*, M.B. Danailov*: Up-converted fluorescence in a Nd:YVO4 laser. In: "Kvantumelektronika 2000", Proc. of the 4th National Symposium on Quantum Electronics (3 November, 2000, Budapest), Ed. S. Varró (SZFKI, Budapest 2000), P16 (in Hungarian)
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Departments > Laser Applications
