ANNUAL REPORT - MTA SzFKI

Q. OPTICAL THIN FILMS
K. Ferencz
Optical thin film structures consisting of nanoscale laminated layers. — We have
continued our research concerning the development of optical thin film structures
containing nanooptically thin layers for advanced applications in laser physics and
information technology. We have refined our new electron-beam deposition technology
for the production of optical coatings containing nanooptically thin titania, silica, tantala,
alumina, hafnia layers. Using needle-like optimization thin film design method, we have
continued our research concerning the development of many kinds of ultrafast nanooptical
coating systems – ultra-wide-band, low dispersion antireflection coatings, low dispersion
beamsplitter coatings, ultrafast dichroic mirrors, wide-band output coupler mirrors,
spectral shape filters for amplifiers, for example. We have found a new application of our
nanooptically thin indium-tin-oxide (ITO) layers deposited with reactive e-beam method in
integrated optical sensor chip technology. Our thin ITO layers having electrical resistance
in the kohm range were successfully applied on the top of waveguide structures, because
their optical absorbance is very low in the red part of the visible spectrum. Using our new
deposition technology we have developed special type wide band ultrafast front polarizer
coatings for the UV, VIS and IR ranges. We have developed new trichroic polarizer beam
splitter coating working at 45 degree angle of incidence. This coating has high reflectance
for the s-polarized light and high transmittance in three separated bands (blue, green, red)
for the p-polarized light in the visible range. The application of our new trichroic polarizer
looks very promising in the 3D display technology. Our work on interference filters is still
in progress for high sensitivity detection of protein molecules elaborated by gene
manipulation methods.
Other developments on optical coatings. — Our work on ultrafast optical coatings is still
in progress cooperating with the Max-Planck-Institute for Quantum Optics, Garching,
Germany (Prof. Ferenc Krausz) for many types of advanced applications in laser
oscillators, amplifiers, autocorrelators, coherent X-ray generation, etc. We have developed
small-scale optical manufacturing technology for producing of large size fused silica
compensating wedges having a few tenths of millimeter minimal thicknesses. We have
arranged a new optical coating laboratory infrastructure financed by company Optilab Ltd.
in our campus, where a new optical coating machine type INTEGRITY 36, manufactured
by the US company DENTON VACUUM will start its operation in the near future. Our
new coating machine manifests the state-of-the-art optical coating technology, the
combination of ion-assisted deposition technology, oil-free cryopumping and a
sophisticated computer control system.
Based on our standard multiple-beam interference method for analysing optical coatings
we have developed a new fast quantitative technique for analysing thin mineral oil films
on water surfaces (project „Aquanal”). Using our CCD array spectrometer we have
investigated the spreading phenomena of different kind of oil materials on water surfaces,
and we have found that the equilibrium thicknesses of the oil films in many cases are much
more thicker than the monolayer thicknesses are. We plane to continue our research in this
field using new type oil samples to understand the details of the interaction between
mineral oils and water surface. Based on our investigations we have developed optical
multilayers useful as cheap sensors in oil contamination detection tasks.
These results were obtained in the frame of the scientific cooperation between the Institute
and the Optilab Ltd.
73