This paper describes real-time, very small and cheap Stokes polarimeter using three polarized beam splitters (PBSs). Each s1, s2 and s3 of Stokes parameters is measured by the PBSs. However this technique has to separate three beams keeping unknown incidental polarization state. To overcome this problem, three same normal beam splitters (BSs) are possible to separated two beams keeping polarized state. An alignment of three BSs is set orthogonal in transmission part and reflection part. In transmission part, the polarization state after two BSs can be canceled change of polarization state of first BS by change of second orthogonal BS. In reflection part is same theory. If you set two pear of this keeping polarization beam splitter, you can separate three beams keeping incidental polarization state. After separated beams, three PBS can measure Stokes parameters easily. At first we checked effect of the keeping polarization beam splitter using spectoscopic Mueller matrix polarimeter. We got Mueller matrixes having max 3.3% value of transmission and reflection from unit matrix during from 450nm to 700nm. In second we checked Stokes parameters after a rotating polarizer and a quarter wave plate in this Stokes polarimeter. In two condition results, an error had 5.6%. Finally we checked measurement speed of this real-time Stokes polarimeter using rotating quarter wave plate. From this result this Stokes polarimeter is possible to measure Stokes parameter in 15Hz. This measurement speed depends on detection speed of six PIN photodiodes and transfer speed of AD convertor.
We introduce partial Mueller matrix polarimeter using two photoelastic modulators and polarizer pairs. Photoelastic
modulators (PEMs) have been used in various kinds of polarization measurement techniques for many years, for
example in polarimetry and ellipsometry. The advantages of instruments using PEMs are their high-sensitivity and highspeed
measurement of polarization properties. A polarized light beam passing through the center of the fused silica bar
will experience a periodic phase retardation because of the photoelastic effect which is the basis operation of PEM. In the
two PEM-polarizer pairs, Mueller matrix elements of a sample are determined based on the analysis of the frequencies of
the time-dependent light beam. Each PEM is operated at different resonant frequencies of 59.85 kHz and 50.07 kHz and
are oriented 45° apart. The polarization information that are to be represented by Mueller matrix is distributed based on
combinations of two resonant frequencies of operating PEMs. Mueller algebra is used to analyze the optical
configuration of the proposed system. The changing variables inside the proposed system will be only the orientations of
the azimuthal angle of polarizer and analyzer whereas orientations for both PEMs are fixed. Polarization information
such as total retardation can be retrieved by using the partial Mueller matrix information based on the proposed
polarimeter. Experimental results of a quarter wave plate will be presented showing the characteristics of the
A four detectors polarimeter is originally invented by Azzam et. al. We have modified their idea and developed a new four detectors polarimeter of a transmission type (T-FDP) which has some advantages over the conventional one. Further modification of our T-FDP to the M-TFDP is reported. The alignment procedure of the optical system is also discussed as the application of the M-TFDP to ellipsometry.
Microlenses were formed directly on a surface of a glass plate by using CO<sub>2</sub> laser. This method has the merit of complete dry processing and presents simple way of microlens fabrication. We discuss about the formation process and mechanism through the characterization of irradiation parameters and the glass composition. When the surface of a glass plate is heated locally to a working point of the glass material by a focused CO<sub>2</sub> laser beam, a microlens is formed owing to surface tension. It was found possible to fabricate microlens easily placed at different focal position by controlling a laser power and an irradiation time. The volume of the fabricated microlens was found to be dependent on laser irradiation energy (laser power x irradiation time) and irradiated position. When a Corning 7059 glass plate was used, a convex microlens was obtained at the energy density smaller than ca.100 (μJ/μm<sup>2</sup> ). The dynamical stress change of the microlens was measured in-situ by using the ellipsometry analysis to make clear the formation process of microlens. The T-FDP (four detectors polarimeter of transmission type) was used for this analysis.
The laser medium made of a single crystal is generally limited in several factors to fabricate large size crystals and to dope optically active elements heavily. For the improvement of these factors, it is proposed to use ceramics for the laser. We have succeeded to fabricate highly transparent ceramics ruby by using CIP and vacuum sintering techniques. The fluorescence spectrum of Cr ions in the ceramics ruby corresponded to that of a single crystal.
We have constructed the four detectors polarimeter of transmission type (T-FDP) whose principle was originally invented by Azzam et. al. Some of the distinct features of our instrument are the liner optical axis and high speed data acquisition of msec order. It can determine the polarization state of the light that passed through the anisotropic materials such as liquid crystals in a very short time. We observed the dynamic change of the polarization state of the transmitted light through the liquid crystals (smectic and super twisted nematic) that are driven by alternating voltage. The behaviors of the both liquid crystals showed hysteresis. We also showed the trajectory of the polarization state observed through the super twisted nematic liquid crystal on the Poincare sphere.
The amorphous GeS<SUB>2</SUB> film is one of the chalcogenide glass and also shows the phenomenon of Ag-photodoping under the illumination of the high-pressure mercury lamp. We have been carrying out the in-situ measurements of the photodoping process of Ag/a-GeS<SUB>2</SUB> films system with a laser probe ellipsometer. In the process of the thickness measurements, we have observed curious changes of ellipsometric parameters (delta) and (Psi) of the GeS<SUB>2</SUB> film sample during the illumination of the laser probe. The results seem to be suggesting that the illumination of the laser beam might engrave the GeS<SUB>2</SUB> film. The power of the laser is less than 1mW and the beam diameter is 1mm. The idea such as an ablation of the GeS<SUB>2</SUB> film seems to be unlikely to interpret this phenomenon.
Microlenses and microlens arrays were formed directly on a surface of a glass plate by use of a CO<SUB>2</SUB> laser. By heating the surface of a glass plate locally to a working point of the glass material using CO<SUB>2</SUB> laser beam, the surface became a hyperboloid owing to surface tension, which resulted in microlens. This method has the merit of complete dry processing. Several types of glass materials were tested. It is important to choose the type of glass with thermostable property with small expansion coefficient. It was found possible to make easily microlens and arrays with different focus lengths by controlling a laser power and a irradiated position. Typically, a CO<SUB>2</SUB> laser power of 1.5W and an irradiation time of 1.1s were used to fabricate a microlens with a 170 micrometers diameter and 181 micrometers focal length with good focusing property. Microlenses fabricated using various beam profiles of CO<SUB>2</SUB> laser were also discussed.
We studied the polarization effect of the normal cornea by using birefringent special samples (PMMA) which produce polarized pattern similar to those of the in vivo cornea. The observation confirmed the change of polarization patterns in vivo cornea as a function of thickness and optical birefringence of the cornea. We posit that the hyperbolic polarized pattern seen in vivo normal cornea is the change of birefringence in the whole cornea is affected by the external oblique direction of stress, which is necessary to maintain a balanced state of the eye globe.
We have equipped an ion assisted deposition system with a rotating-analyzer ellipsometer (RAE) for in-situ monitoring of the deposition process. We propose the optimum conditions for the SiO<SUB>2</SUB>/Si substrate system for observation of growth processes of Au film deposition. The deposition of Au films on optimized silicon oxide substrates was observed in- situ using the RAE. The growth curves for Au films were different from those for continuous layer growth in the initial stage. The critical thickness at which the growth became continuous layer growth varied with the irradiated current density of Ar ions. The ion-current density for the minimum critical thickness of Au films has an optimum value of around 100 (mu) A/cm<SUP>2</SUP>. The initial stage of Au growth before continuous layer growth occurred was analyzed using the Maxwell-Garnett theory and semi-quantitative agreement was obtained between the experimental and calculated results.
Polarization modulated spectroellipsometer was utilized to monitor, in-situ, deposition of Ag on Si substrate. The angle of incidence was determined using a Si substrate covered with native oxide. In the wavelength region of 550 nm to 700 nm, the ambiguity of the angle of incidence was within 0.2 deg. A plasma resonance peak manifested in reflectance spectrum around 350 nm increased and shifted to shorter wavelength as the deposition time increased from 1 sec to 10 sec. (Delta) (Psi) trajectory approached to a simulation curve of a continuous film as the deposition time increased to 40 sec where the film thickness was estimated to be 20 nm.
The process of photo-stimulated dissolution of Ag atom/ion into amorphous chalcogenide materials As<SUB>2</SUB>S<SUB>3</SUB> was observed in-situ by ellipsometry. The sample was Ag/As<SUB>2</SUB>S<SUB>3</SUB> film system which was deposited onto the glass substrate. The photodoping was proceeded by the irradiation of the light of 546:1 nm. Obtained values of ellipsometric parameters (Psi) and (Delta) were fitted by using a multilayer model. Time dependent changes of each thickness of Ag, Ag:As<SUB>2</SUB>S<SUB>3</SUB> and As<SUB>2</SUB>S<SUB>3</SUB> layers during the diffusion process were derived. These behaviors will be explained in relation with photodoping mechanism.