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- New Deposition Techniques
- New Applications
- Active Films
- Characterization and Properties
- General Topics
- Active Films
New Deposition Techniques
Optical thin-film technology: past, present, future
William P. Strickland
Show abstract
The evolution of the vacuum coating industry is reviewed. Vacuum science progressed slowly until the late
nineteenth century due to an incomplete understanding of vacuum and lack of applications. Edison's invention
of the light bulb launched the vacuum industry and increased developmentof improved vacuum systems. The
thin film optical coating industry arose from the needs of the German and U.S. military efforts during World War
II. The author presents his experience in thin film coating from 1939 to the present.
Cluster size in ionized cluster beam deposition
Frank K. Urban III,
Alfred I. Bernstein
Show abstract
A unique aspect of the Ionized Cluster Beam (ICB) thin film deposition
method is that material is deposited as ionized,accelerated atom clusters. Results
of one laboratory suggest that a wide range of beneficial film formation effects can
be attributed to the clusters, reported to average 1000 atoms in size. We present
two cluster measurement methods here to investigate these claims. In the first, the
depositing beam passes through an ionizer, a slit and an electrostatic deflection
field. An undeflected neutral deposit and an ionized deflection deposit form on a
single crystal silicon substrate. The ratio of atom flux to charge flux in the
deflected deposit is equal to the number of atoms per singly charged cluster. In the
second method, a low amplitude 10 KHz signal modulates the electrostatic
deflection field. The phase shift between the modulation voltage and the measured
substrate current yields particle velocity from which mass can be obtained. We
have confirmed the presence of small, three atom gold clusters.
Ion currents and energies in reactive low-voltage ion plating: preliminary results
Show abstract
Reactive Low-Voltage Ion Plating (RLVIP) is a plasma-assisted evaporation process
that produces anorganic oxide- and nitride films with a closed microstructure. in
order to better understand the process and the resulting film properties a BALZERS
PPM 400 Plasmamonitor, a combination of a quadrupole mass filter and an energy
selective ion optics, has been used to study the relative abundancies and energy
distributions of the ions impinging on the growing film in the RLVIP process. The
device is discussed and preliminary results are presented: The plasma is anisotropic.
Surprisingly it contains ions with higher energies than expected from the
self-bias potential.
Recent advances in reactive low-voltage ion-plating deposition
Karl H. Guenther
Show abstract
Because of the improvement of several thin film properties and the relative ease of transference
into a production environment, reactive low voltage ion plating (RLVIP) has found its way into industry
at several optics and thin film manufacturers. In this review of recent accomplishments achieved with
this process at our laboratory as well as at other institutions we will first recall the underlying principles
of operation and some of the improved properties typical of thin films made by RLVIP. Then
follow examples of applications exploiting these significant improvements, including coatings for surface
smoothing, antireflection coatings for the 2 - 5 pm wavelengths range, non-shifting edge filters
and thin film polarizers, narrow band reflectors (laser protection filters), and laser mirrors. The paper
concludes with a brief account of the advantages - and disadvantages - of this process compared with
conventional electron beam evaporation and deposition processes employing a directed ion beam.
Radio frequency and microwave plasma for optical thin-film deposition
Juergen Otto,
Volker Paquet,
Ralf Th. Kersten,
et al.
Show abstract
For the next generation of fusion lasers reflecting mirrors with laser damage thresholds of at least
40 J/cm2 for 1 0 ns laser pulses at 1 .064 pm are needed. Up to now, no deposition technique has
been developed to produce such mirrors. Best R&D-values realized today are around 30 J/cm2 for
e-beam evaporated mirrors. R&D on conventional e-beam coating processes over the last 1 0 years
has come up with marginal improvements in laser damage thresholds only. However, new technologies,
like PICVD (Plasma-Impulse CVD) developed for the fabrication of ultra-low loss fiber preforms,
seem to offer the potential to solve this problem. First results have been reported already [1-3]. It
is well known that fused silica produced by CVD processes can have laser damage thresholds as
high as 80 J/cm2. However, the thickness of a single deposited film is in the pm-range for most
of the CVD-processes used for preform manufacturing; since interference optics need films in the
; /4n range (where n is the refractive index of the dielectric material) the use of preform-fabrication
processes for the purpose of interference mirror fabrication is limited to a few plasma based CVD
technologies, namely PCVD (Plasma-CVD, Philips [4]; PICVD, SCHOTT [5]). Especially PICVD is a
very powerful technology to fabricate thin film multilayers for interference mirrors, because this technique
is able to produce films down to monolayer thickness with nearly perfect stoichiometry and
morphology. In first and preliminary experiments the usual deposition in a circular tube at high temperatures
has been used for simplicity. However, to produce large area high quality laser mirrors
this principle know-how has to be transfered from circular to planar geometry. Experiments showed,
that there may be some limitations with respect to the homogeneity of a planar deposition using
microwave excitation for the plasma. Therefore experiments have been performed in parallel with
both RF and microwave excitation for comparison. In the following we will restrict ourselves to the
description and discussions of the planar processes; the principle and details of the PICVD-process
are described elsewhere [5] while RF-plasma technology is a well known process.
Optical and electrical properties of transition metal nitride films produced by reactive cathodic arc deposition and reactive rf sputtering
Paul Kraatz,
F. Russell Nakatsukasa,
John W. Stephenson
Show abstract
Thin films of titanium, zirconium, and hafnium nitride have been fabricated by reactive cathodic
arc deposition from elemental targets in a nitrogen ambient. The optical constants n and k of
these films have been measured ellipsometrically from 0.40 to 0.70 m. Refiectances have been
measured from 0.40 to 16 jim. Electrical properties have been evaluated using sheet resistance
and Hall mobility measurements. Values for cathodic arc TiN films are compared with data for
TiN films fabricated by reactive RF bias sputtering from a titanium target in an argon/nitrogen
medium. Measured film properties are correlated with deposition parameters and qualitative
studies of microstructure and surface topography.
Electron-rain-assisted deposition of optical thin films
Jiu Lin Zhou,
Zi Ma,
Qian Ru Liu
Show abstract
A hollow cathode electron/ion source with permanent-magnet-field was introduced to assist depositing oxidemetal optical coatings. The refractive index ,absoption and scatter of as -deposited layers arediscussed. It wasfound that the optical loss (absoption and scatter) decreased under proper depositing conditions. The optirnumevaporating parameters were obtained through orthogonal experiments.
Effect of ion-assisted deposition on optical properties of thin films
Xuefei Tang,
Zhengxiu Fan
Show abstract
Effects of ion assisted deposition on the propertes of Ti02, Zr02 and 5102
optical coatings were investigated. Substrates were bombarded with different ions---
oxygen ions , argon ions , and the mixture ions of oxygen-argon during deposition.
The refractive indices, optical absorptions and laser-induced damage thresholds
(LIDT) measurments of these films are reported.
New Applications
Optical coatings for automobiles
Ferdinand Trier
Show abstract
The windows of modern automobiles are growing larger and larger. The larger the window, the greater its
angle of inclination. This causes some problems for the passengers and their compartment. One well-known
problem is the heat irradiation into the car. For a long time green tinted glass has been used to solve this
problem. Some coatings have been developed to solve this heat problem. But with greater angles of
window inclination a new problem appears: the visible light transmittance decreases. At an angle of 70°
the transmittance through the windshield is only 50% from the driver's viewpoint. The only way to solve
this problem is by special antireflection coating. First tests with such coatings have shown that it is
possible to achieve both the right optical function and the necessary hardness.
Plasma-enhanced CVD hard coatings for opthalmic optics
Show abstract
To protect the soft surface of organic CR 39 ophthalmic lenses we
built up a parallel plate reactor and developed a Plasma Enhanced
Chemical Vapor Deposition (PECVD) process for Si02 protection films.
Beside high transmission in the VIS-range we obtained refractive
indices between n=1.46 and n=l.49 depending on the process parameters
at layer- thicknesses of 2,5 jnn to 5 jmt. Deposition rates up to 30 A/s
and thickness uniformities of 10 % were achieved. The mechanical
properties of these layers were tested with different methodes and
gave better results compared with other technologies like ion-assisted
deposition or lacquering.
Optically variable films, pigments, and inks
Show abstract
Optically variable thin film coatings have been prepared on rolls of polyester film by depositing thin
multi-layers in a vacuum roll coater. Such coatings can be removed from the polyester film and
ground into optically variable pigments for printing inks. Various printing inks including gravure,
flexographic, and Intaglio inks have been prepared from these pigments, and printed images using
these inks have been obtained from commercial printing presses. These optically variable systems have
been used on various security documents to prevent counterfeiting with color copiers. Unique colors,
color shifting effects, and other optical properties have been obtained by combining non-optically
variable pigment and dyes with this light interference pigment. The merits of this new ink relative to
other optically variable systems are color uniformity, print quality, its ready use on existing printing
presses, and high security.
Simple antireflection coatings for cathode ray tube and other display devices
Joachim Szczyrbowski,
Stephan Roegels,
Klaus Hartig
Show abstract
Some interference filter with antireflecting, antistatic and contrast
enhancing effects were investigated both by computer simulations
and experimentally. The aim was to prepare such coatings for TV
cathode ray tubes and display devices on large scale by magnetron
sputteritig. To avoid large values of the thicknesses of the individual
films ( high preparation cost) and to achieve the antistatic and contrast
enhancing effect an electrical conducting and light absorbing
layer is embedded between insulating, non-absorbing films. For the
mechanical durability a hard material as TiN, ZrN or HfN was taken
into account. Good results were obtained with TiN. As an example, the
obtained total thickness of a three layer filter with a light ref lectance
lower or equal 0.4 % and a light transmission of 30 % was about
100 mu. The sheet resistivity for this filter is of about 300 Ohm.
For a conventional dielectric filter with the same antireflecting
result the total thickness is usually of about 250 nm. Finally, two,
three and five layer filters were successfully prepared on an industrial
sputtering coater.
MetaMode: a new method for high-rate MetaMode reactive sputtering
Richard Ian Seddon,
Paul M. Lefebvre
Show abstract
A new system has been developed.for DC reactive magnetron sputtering. This system
features enhanced oxidation rates and near metallic sputtering conditions. It is particularly
well adapted for coating complex multilayer films and for depositing uniform thickness
films on small to moderate size planar and nonplanar substrates.
Thin-film coatings for flexible optical data storage
Andrew J.G. Strandjord,
Steven P. Webb,
Donald R. Beaman,
et al.
Show abstract
A write-once optical data storage media has been developed which is suitable for tape formats. The
recording layer is a metal alloy system which is sputter deposited onto polymeric substrates as a
single-layer thin film. The media are manufactured using a continuous sheet process, where the
reflectivity of the film at 840nm can be selectively varied between 30 and 70%.
These films have been characterized for laser write sensitivity, optical properties, surface chemistry,
and environmental stability.
An abrasion resistant hard overcoat is applied directly onto the active surface in a second vacuum
deposition step. The media performance has been found to be compatible with direct hard-overcoats
with no degradation in write sensitivity.
Multilayer thin-film media for optical recording
Show abstract
A write-once optical data storage media has been developed which is suitable for tape formats. The
recording layer is a metal alloy system which is sputter deposited onto polymeric substrates as a
single-layer thin film. The media are manufactured using a continuous sheet process, where the
reflectivity of the film at 840nm can be selectively varied between 30 and 70%.
These films have been characterized for laser write sensitivity, optical properties, surface chemistry,
and environmental stability.
An abrasion resistant hard overcoat is applied directly onto the active surface in a second vacuum
deposition step. The media performance has been found to be compatible with direct hard-overcoats
with no degradation in write sensitivity.
Production of magneto-optical data storage media by static DC sputter processes
Guenter Braeuer,
Wilfried Dicken,
Sabine Mueller
Show abstract
Static sputter processes for the mass production of 5.25" magneto-optical data storage
media have been developed. Such single disk processes require a discontinuous operation
of circular magnetron cathodes in nonreactive and reactive gas atmospheres.
Magnetron field configurations based on specially shaped rotating magnet patterns allow
to meet high uniformity criteria for optical and magnetic properties of the individual
layers using 210 mm targets and an integrated inner/outer diameter disk masking.
The processes have been integrated into avery compact 'circular path coater'
which realizes a throughput of 180 disks/hour. Experimental results of the process
development for SiN and TbEeCo thin films are presented.
Active Films
Thin films for active optics
Solomon Musikant
Show abstract
The Kodak 2 .5m Ion Figuring System (IFS), intended for the final figuring of large optics using a directed
inert neutralized ion beam, has been installed and is operational. Process development and production implementation
efforts are currently underway. Thermal heating effects due to exposure to the ion beam removal function
are discussed. Details of processing and results from an ion figuring correction of a 0.Sm lightweighted optic are
presented.
Electrochromics and potential automotive applications
Show abstract
Electrochromics are reviewed in this paper. Known and new electrochromic
materials are summarized and properties of electrochromic device elements and
classical and new type of electrochromic devices are given herein. Requirements
of the electrochromic glasses are studied depending on the application area,
and processmateria1-requireinent relationships are examined. Potential car
applications and futuristic cars with electrochromics are also reviewed.
Electrochromic films involving Prussian blue and viologen materials
Melvin H. Miles,
D. A. Fine,
David E. Stilwell
Show abstract
Prussian blue (PB) and viologen materials color by electrode oxidation and reduction reactions, respectively;
therefore, it may be possible for these materials to function in a complementary fashion in an electrochromic optical filter.
The soluble viologen compounds deposit as a colored film during the cathodic reaction and go back into solution when the
current is reversed for the erase cycle. Prussian blue, in contrast, is prepared as a permanent film that can be switched back
and forth from the colorless to the blue form. In this study we have determined some of the major factors leading to longterm
cycle stability for viologen and Prussian blue films. The pH of the tlectrolyte is a major factor in the film stability for
Prussian blue. Life-times in excess of 100,000 cycles were easily achieved for Prussian blue films in solutions of pH =2.
In contrast, none of the films tested in neutral solutions showed a lifetime exceeding several hundred cycles. For viologen
materials, major factors affecting cycle lifetimes are the molecular structure of the viologen along with the electrolyte and
solvent compositions. The use of several mixed electrolytes such as KNO3IK2SO4 as well as the use of mixed solvents can
greatly increase the cycle stability of some viologen compounds. In fact, the failure mechanism for viologen films can be
completely defeated by the appropriate viologen/electrolyte/solvent selection. The complementary behavior of Prussian blue
and viologen films will be investigated at electrolyte and solvent compositions favorable for cycle stability.
Optical, thermal, and electronic semiconductor properties of thermochromic metal halides
Thomas Novinson,
Jeffrey I. Zink,
John Kennedy,
et al.
Show abstract
Silver mercury tetraiodide (Ag,HgI ) is a well known thermochromic pigment that
changes color from yellow to ornge at 50 C. The compound is also a fast ion conductor
above its phase transition temperature. We synthesized a number of analogues
of this compound in which the silver was replaced by cadmium, lead, thallium(I),
copper(I), indium(I), gold(I), lithium, cesium and rubidium to determine the range
of color transitions and the correlation of electrical conductivity with optical and
thermal activity. This paper also reports on continued research to assess the
possibility of using these pigments in architectural coatings.
Herpin equivalents in magneto-optics: a magneto-optic layer sandwiched between two dielectric layers
Vahram W. Biricik
Show abstract
Magneto-optic elements are important in applications requiring frequency shifters. Certain
applications require the incorporation of magneto-optic layers into a multilayer optical stack.
This paper is concerned with the development of design methodology for maximizing magnetooptical
effects. To aid in this developmental process, the well-known concept of thin film
Herpin equivalent structures is extended into magneto-optics; specifically, the magneto-
optical analog of Herpin equivalents is derived for a thin magneto-optic layer sandwiched
between a symmetric pair of dielectric films.
The magneto-optic configuration selected is that of the Transverse Kerr effect; that is, the
magneto-optic layer magnetization lies in the plane of the film and is in a direction perpendicular
to the plane of incidence. For this geometry, magneto-optic effects manifest themselves
only for the p (in-plane) polarization. As part of the derivation process, reflectance and
transmittance expressions are derived for a symmetric three-element film configuration. It is
shown that the magneto-optic effects only manifest themselves in reflection; in other words,
the transmitted electric field does not contain a magnetization dependent term.
Additionally, as the direction of propagation of the light wave is reversed (with the electric
field incident on the three layer structure from the back surface), the magneto-optic signal
changes sign, indicating non-reciprocity of the coupling between the light waves and thin film
magnetization. It is also shown that the magnitude of magneto-optic effects depends only
on three terms: (a) the reduced magneto-optic coefficient of thin film material; (b) the phase
thickness of the magneto-optic layer; and (c) the transmittance of the three layer structure.
Photoconducting and photoelectrochemical characteristics of selectively plated cadmium selenide films
Show abstract
Thin films of cadmium selenide were prepared for the first time by a selective
plating technique on conducting glass and titanium substrates. The films were
characterised bymeans of x-ray diffraction, scanning electron microscopy, optical
absorption, photoconductivity, and photoelectrochemical (PEC) studies.
Characterization and Properties
Thermal properties of optical thin-film materials
Donald L. Decker
Show abstract
A survey of experimental methods and data for thin-film thermal conductivity and heat
capacity is given. Simple microscopic theory is provided as a basis for understanding the
very small values of thin-film thermal conductivity observed. Interfacial resistance
effects, including some conjecture on origins, as well as applications of thermal property
data are discussed. The needs for future development of this important area of investigation
are summarized, and some suggestions for emphasis are provIded.
Minimizing defects in infrared coatings on silicon
Show abstract
Studies were made of the origins of defects in multilayer coatings used as high reflectors in the infrared, with the aim
of reducing the numbers of defects and increasing the laser-damage threshold for the coatings. Clean-room conditions were
found to be essential for cleaning and coating low-defect substrates. The levels ofsurface and subsurface defects on the substrate
were the most important parameters in determining defects on a completed coating. Although the initial chromium film on the
silicon substrate appeared to contribute many defects, it was actually making visible submicron defects that were already on the
substrates. When the vacuum coating system was operated under clean conditions, the multilayer coatings added few defects
to ones already present. Defect densities were reduced by a factor of 100 during the course of the study, resulting in a significant
improvement in the laser-damage threshold of the coatings.
Mechanical properties of thin films on substrates
Shefford P. Baker,
William D. Nix
Show abstract
Thin films that are used primarily for their optical, electronic, magnetic and chemical properties are not generally
considered to be structural elements. Nonetheless, when thin films are auached to substrates, they are often found to support
very high stresses which can cause both deformation and fracture to occur. Thus, the mechanical properties of thin films on
substrates are of technological importance. In particular, the mechanical properties of optical thin films must be sufficient to
insure their mechanical integrity and dimensional stability over the lifetime of the device in which they are used. The origins
and consequences of internal stresses in thin films and variations in strength and stiffness from those expected of bulk
materials are discussed. Two measurement techniques are presented. In the first, curvatures induced in a substrate by stresses
in an attached thin film are measured to determine those stresses. The second technique involves determining the hardness and
elastic modulus of a thin film while it is attached to a substrate using a depth-sensing indentation device.
Ion-beam-sputtered metal fluorides
Thomas H. Allen,
John Philip Lehan,
Larry C. McIntyre Jr.
Show abstract
Dense, water-free magnesium and calcium fluoride films were produced by Reactive Ion Beam
Sputtering (RIBS). These films were found to J.e fluorine deficient because of a preferential
sputtering of fluorine at the target This deficiency was eliminated by the addition of a fluorinecontaining
gas (carbon tetrafluoride) to the coating chamber gases during deposition of the films.
The chemical composition and density of the films were measured with Rutherford backscattering
spectrometry. The relationship between film composition and optical properties was investigated.
The results indicate that the fluorine deficiency can be eliminated without compromising either the
density or environmental durability.
Properties of reactively deposited SiC and GeC alloys
Show abstract
Thin-film silicon carbide (SiCi) and germanium carbon (Ge,Ci) alloy coatings with low Üifrared optical absorption
have been fabricated by DC- and RF-reactive magnetron sputtering. The optical and mechanical properties of the coatings
depend on composition determined by deposition conditions. The refractive index and optical absorption coefficient of
SiCi. alloys were varied from those of amorphous Si to those near diamond-like carbon (DLC) by increasing C
content. The band edge shifted below 1.2 eV with C content as high as 0.8. The useful range of the SiCi coatings
was extended to wavelengths as low as 1 jim. The useful transparency range of GeCi coatings is from 3 to 12 jim.
The refractive index of GeCi coatings was varied from 4.2 of amorphous Ge to near 3.4 by increasing x from 0 to 0.5.
The optical absorption coefficient was a complex function of composition and C-H, Ge-H, and Ge-C bonding. Mechanical
stress in both materials was generally moderate, and increased with increasing C content for the GeC alloys and
decreased with increasing C for the SiC alloys.
The wide range of optical properties obtainable for both coating types makes them useful in many types of multilayer
designs. Abrasion-resistant infrared (IR) multispectral antireflection coatings on zinc sulfide (ZnS) were demonstrated
using Geij•9C and DLC layers.
Medium energy backscattering spectrometry: a new tool for characterizing optical thin films
Marcus H. Mendenhall,
Robert A. Weller
Show abstract
We have developed a new method of analyzing surfaces and thin films based on time-of-flight analysis
of backscauered particles. The technique employs ions with incident energies from a few tens of keY up
to about 500 keY. It combines the quantitative prowess of Rutherford backscattering spectrometry with
increased surface sensitivity, increased depth resolution and reduced target damage. Several probe species
have been used successfully for analyses with He and Li at 250 keY and C2 at 500 keY being particularly
useful because of the range of cross sections and resolutions for depth profiling that they offer. This
paper describes the technique and presents studies of the composition of beryllium surfaces for mirror
applications and of He indiced erosion of CaF2 and MgF2 films on Be substrates, simulating the
exposure of optical coatings to one type of radiation found in Earth orbit
Automated precision reflectometer for first-surface mirrors I: optical head
Erik W. Anthon,
Luis F. Villanueva,
Craig Van Horn,
et al.
Show abstract
Multilayer-overcoated, high-reflector mirrors in sizes up to 30" x 50" areproduced on a continuous
coating line. A fully-automatic, highly-accurate scanning reflectometer has been built as part of the
process-control system for the continuous coating line. The reflectometer covers a spectral range of
380 to 800 nm and a range of incidence angles of 15° to 6O. The s- and the p-polariation
components of reflectance are scanned separately.
The reflectance measurements are absolute and are not referenced to a calibrated standard reflector.
The absolute measurement accuracy is
This paper describes the optical system used in the reflectometer.
Automated precision reflectometer for first-surface mirrors II: system
Luis F. Villanueva,
Tom Engel,
Richard Ian Seddon,
et al.
Show abstract
A computer-controlled spectrometer has been built for measuring high-reflectance mirrors in the
visible region (380 800 nm). The instrument is designed to scan high-reflectance mirrors (greater
than 50%) on a surface up to 32 x 50 in. Plots of complete reflectance scans are available in minutes
and are used for process control. The reflectometer can be set to any desired incidence angle in the
range of 15 to 60° and four different polarization modes can be selected: P, S, P&S, and No
Polarization.
The instrument incorporates several techniques in order to perform as an absolute system with an
overall accuracy of better than 1% . The optical system features double-bounce reflection, a
special integrating-sphere light source, a double-stage monochromator, and a high-uniformity,
9-stage, side-on photomultiplier tube.
This paper will focus on the electronics, controls and computer system used in the reflectometer.
Some physical properties and microstructure of titania films doped with multielement
Longsheng Qian,
Tongqun Miao,
Youxin Yuan,
et al.
Show abstract
The chemical composition, refractive index, texture thermal
stability and microstructure of the films, by evaporating T102
mixed with elements of TaO5, YO3, and Mo , at the substrates with
temperature of room, 180°c and 250° c, were investigated. The
results showed that chemical composition of the films is different
corresponding to not only that of materials and substrate
temperature but also the manufacturing device. Both thermal
stability with respect to crystalline temperature and rnicrostructure
were different due to both the substrate temperature and chemical
composition of the films/or coating materials.
General Topics
Method of monitoring nonquarter-wavelength film thickness by turning point
Anmin Zheng,
Yixun Yan,
Fengshan Zhang
Show abstract
A method is presented for nionitoring Taultilayer structures
with nonquarter wavelength thickness. This method is similar to the
conventional turning point method, except that the irronitoring
wavelength selected by adniittance diagram will be changed with
layers. Results are given for the use of this method in depositing
Antireflectance coatings (ARC.)
Dependence of precursor chemistry and curing conditions on optical loss characteristics of polyimide waveguides
Show abstract
Planar Waveguides were fabricated from three polyimide samples
differing significantly in terms of their precursor and curing
chemistry. The samples were selected from the groups of
non-photosensitive preimidized, photosensitive preimidized and
photosensitive polyamic ester precursor based polyimides. We observed
significant differences in the waveguiding characteristics of these
films which demonstrate the critical role of precursor chemistry on
the optical properties. Curing conditions such as heating rate and
bake duration also affected the optical properties. A scattering
loss of less than 0.7 dB/cm was measured for waveguides fabricated
from the photosensitive preimidized samples. On the other hand the
photosensitive polyamic ester bas,ed samples registered a loss of
greater than 1.5 dB/cm. In general the scattering loss increased with
the bake temperature. The magnitude of the increase was much higher
for the photosensitive polyamic ester based samples. UV exposure
also affected the waveguiding characteristics and caused formation
of scattering centers as evidenced by the increase in the scattering
losses associated with these waveguides. Planar waveguides based on
photosensitive preimidized precursor, retained excellent lightguiding
properties even after high processing temperatures (Optical losses in
these waveguides remained below 1.0 dB/cm after a 300 °C bake).
Investigation of tellurium thin films for IR-integrated waveguides and CO2 laser detection
Show abstract
Mode concentration and propagation constants in Te thin film structures are readily obtained from a transverse
resonant method without explicit knowledge of the dispersion relationship from Maxwell's equations. Losses involved,
best method of coupling a light beam into a Te thin-film waveguide, non linear Te-X-junctions, bends co and contradirectional
coupling, second order harmonic generation (SHG) in a Te Waveguide structure, are briefly discussed.
Finally the measured optimized detection characteristics of Te/Si thin film device and the proposed theory of the
detection mechanism yield to consider Te thin-films as a potenthlly improved room temperature pulsed C02 laser
detector.
Active Films
Deposition methods and process techniques for the fabrication of electrochromic all-solid-state devices
Klaus Muecke,
Frank Boehm,
Thomas Gambke,
et al.
Show abstract
The electrochromic behavior of all solid state devices (ASSDs) is connected with
deposition methods and process techniques for production. Cathodically and
anodically colored electrochromic materials and solid state electrolytes are compared
and the influence of films prepared by reactive evaporation and reactive sputtering
is described. In addition, the general electrochemical behavior of films is discussed,
whiéh are produced by chemical vapor deposition, dip coating, electrodeposition and
anodic oxidation.