Possibilities of holographic recording and laser lithography usage
for forming of Diffractive Microoptical Elements into thin films
of As-S system were studied in present thesis. Both theoretical
and experimental aspects of problem were investigated.
In the literature review section is brief explanation of
diffractive elements principles, holographic recording and
previous use of As based amorphous thin films as a recording
The diffractive properties, in particular diffractive efficiency
(DE), of expected diffractive elements were simulated numerically
for both sinusoidal and rectangular grating shape and for the
wavelengths of 632.8, 1064 and 1500 nm, chosen with regard to
possible applications. From the simulations is clear that high
DE's to chosen order can be achieved, even for the considered
The set of As-S system bulk samples was prepared from pure
elements by melt quenching. The compositions of systems
investigated were chosen with regard to previous research and were
AsS, where the was and 40. Thin
films of various thicknesses and compositions were deposited by
Sensitivity, etching selectivity and characteristics were studied.
The best results were observed on samples of AsS
system. Selective etching phenomenon was used to transform exposed
mixed amplitude/phase elements to phase (surface corrugated)
elements. As etchants the Triethylamine or Propylamine were tested
and Dimethylsulfoxide or Dimethylformamide were tested as solvents,
all in various concentrations.
For various film thicknesses the optimal exposure dose, etching
time and concentration were found. Compared to holographic
recording (514.5 nm), approximately 100 times higher sensitivity
of used system was observed for the wavelength of 441 nm used for
the laser lithography. Some of prepared elements were
characterized by usage of DE, AFM and REM measurements. Observed
DE's were in good agreement with numerical simulations for
accordant depth, period and profile.
From the collected theoretical and experimental data can be
concluded that, after minor problems will be solved, both
techniques are highly usable for diffractive elements preparation.
Used amorphous As-S films have numerous advantages, compared to
conventional materials, in particular very high index of
refraction and wide spectral region of high transmission,
practically from 0.6 to 12 m.
It was proven that highly efficient elements, diffracting the most
energy to any arbitrary diffractive order, could be designed and
prepared by both used techniques.