Plasmonic nanograting consisting of thermally-driven Au/SiO2 bimorph beams is developed that modulate birefringence for at the visible wavelength. From electromagnetic field simulation, the phase difference at 650 nm is calculated to be modulated from 68.5 to 23.5 degree by actuating bimorph beams. The phase difference of fabricated modulator was measured at the wavelength range of from 500 to 800 nm with a driving voltage of 10 V. Phase modulation is obtained, and the maximum variation is -3.3 degree at 646 nm. The maximum drive current is 100 mA.
We proposed and developed high aspect gold metasurface in order to improve the transmittance of plasmonic
micro half-waveplate. Expected transmittance reaches 60% from the FDTD calculation. The metasurface is
fabricated through electron beam litography (EBL) and lift-off process. Fabricated retarder was evaluated
using polarization microscopy. Achieved retardation and transmittans were 144 degrees and from 25 to 40%,
respectively. Four metasurface half-waveplates were arranged and applied to an ultrasmal radial polarization
converter.
We propose and demonstrate a novel visual encryption device composed of higher-order birefringent elements. When an
optical material with higher-order birefringence is placed between a pair of polarizers and illuminated by white light, it
appears only white. In contrast, when it is illuminated by monochromatic light, the transmitted intensity varies depending
cosinusoidally on the wavelength. An array of such materials can express information (e.g., letters and/or images) by
controlling the birefringence of each pixel. If birefringence phase retardation can be adjusted for a specific wavelength,
the information will be clearly displayed when it is illuminated at this wavelength. We denote this wavelength a key
wavelength. The encryption device was fabricated by controlling the amount of higher-order birefringence to achieve
high contrast only by using polarized illumination at the key wavelength. Thus, the information stored in the encryption
device can be decoded only by illuminating it at the key wavelength.
To demonstrate the validity of this encryption principle, we constructed a 3 × 3 pixel device in which commercial retarder
films were laminated. The device was illuminated by a monochromatic light. When a readout experiment was performed
using the monochromatic light at the key wavelength, the stored letter was clearly visible. On the other hand, when pixel
brightness was randomly distributed with illumination at the wavelength other than the key wavelength, the letter could
not be recognized.
Furthermore, the stored information can be easily distributed to multiple physical keys that display arbitrary images. In
this case, the birefringence phase retardation is obtained by summing the values of retardation of each pixel of the
physical keys. In the experimental device, the observed image was decoded by superimposing the two images using
different physical keys.
We proposed a novel pH measurement method based on two-photon fluorescence excitation of a dual-wavelength pHsensitive
dye combined with scanning near-field optical microscopy (SNOM) that can be used to evaluate mitochondrial
activity. Mitochondria produce ATP using a proton concentration (pH) gradient generated between both sides of their
inner membrane. Thus, pH distribution around mitochondria can change with time when mitochondria produce ATP.
This pH distribution has attracted interest because of its influence on necrotic cell death. Because ATP depletion causes
necrotic cell death, measurement of pH distribution around mitochondria is expected to lead to clarification of the
mechanism underlying necrotic cell death. However, it is very difficult to accurately measure pH around mitochondria
using conventional pH measurement methods. In this study, a dual-wavelength pH-sensitive dye was excited locally
using two-photon fluorescence excitation. In addition, collection-mode SNOM was used to avoid reabsorption by
collecting the fluorescent light directly from a florescence point. Using this method, we successfully calibrated pH and
observed temporal variations in pH after dropwise addition of acid. Moreover, mitochondrial activity was successfully
observed based on these pH changes.
To evaluate the thrust produced by photon pressure emitted from a 100 W class continuous-wave semiconductor laser, a
torsion-balance precise thrust stand is designed and tested. Photon emission propulsion using semiconductor light
sources attract interests as a possible candidate for deep-space propellant-less propulsion and attitude control system.
However, the thrust produced by photon emission as large as several ten nanonewtons requires precise thrust stand. A
resonant method is adopted to enhance the sensitivity of the biflier torsional-spring thrust stand. The torsional spring
constant and the resonant of the stand is 1.245 × 10-3 Nm/rad and 0.118 Hz, respectively. The experimental results
showed good agreement with the theoretical estimation. The thrust efficiency for photon propulsion was also defined. A
maximum thrust of 499 nN was produced by the laser with 208 W input power (75 W of optical output) corresponding to
a thrust efficiency of 36.7%. The minimum detectable thrust of the stand was estimated to be 2.62 nN under oscillation at
a frequency close to resonance.
The size of a particle smaller than the diffraction limit is measured using a conventional optical microscope by
adopting a standing wave evanescent field illumination. The scattering intensity from a nanoparticle is periodically
modulated by shifting the intensity fringes of standing evanescent field. By measuring the intensity variation of scattered
light during one cycle of modulation, particle sizes can be easily estimated. Furthermore, this technique has weak
dependence on the material of particles. From the experimental result, the particle size ranging from 20 to 250 nm is
successfully determined. This technique offers a low-cost size measurement for nanoparticles.
Dynamics information of nematic liquid crystal (NLC) in In-Plane-Switching (IPS) mode is attractive and important
for applications of high vision angle techniques. In this paper, we used a novel evaluation method to detect the molecular
orientation dynamics of NLC thin film in depth direction from its birefringence responses using birefringence scanning
near-field optical microscopy (Bi-SNOM). In this method, a Bi-SNOM probe is inserted into IPS mode NLC thin film, in
which the time responses of LC molecules at different position in depth are also measured. In addition, Molecular
orientation hysteresis to the applied voltage is observed. We measured the orientation hysteresis of LC molecules at
different position along the depth direction in the LC thin film. Experimental results show that the proposed method is
effective and feasible for its consistence with original specialities.
KEYWORDS: Liquid crystals, Molecules, Thin films, Birefringence, Near field scanning optical microscopy, Second-harmonic generation, Near field optics, Glasses, Near field, Optical microscopes
Information of molecular orientation in nematic LC (liquid crystal) is attractive and important for application in the
field of display device. In this paper, we demonstrate a novel method using Birefringence Scanning Near-field Optical
Microscope (Bi-SNOM) with a probe which is inserted into the LC thin film to detect the molecular orientation from its
birefringence responses in the thickness direction of LC thin film. The probe is laterally vibrated while going forward
into LC thin film, and the retardation and azimuth angle are being recorded as the probe going down. Since the affection
of shear force acts as a stimulation to LC molecules, the orientation of molecules is changed and reorientated. In this
study, LC thin film on homeotropic alignment LC film and homogenious alignment LC film were measured. In the case
of homogenious alignment LC film, we propose two experiments; one is the experiment in which the vibration direction
of probe is vertical to the alignment direction of PI film, and in the other experiment, we vibrated the probe in the
direction parallel to the rubbing direction of alignment layer. We also compared the data measured with no vibration
probe and the data measured with probe vibrated vertical to the alignment direction. As results, we obtained the
orientation of molecules above the alignment layer by the birefringence response of LC molecules to the disturbance of
vibrating probe and the anchoring extrapolation length by Polyimide (PI) alignment substrate. Ultimately, the LC thin
film can be modeled in thickness direction from all the results using this method.
Optically driven actuators are a non-contact method for the remote application of light energy. We propose a new method for optically driving actuators which uses three polyvinylidine difluoride (PVDF) cantilevers as the legs and a polymer film as the body. The PVDF cantilevers are coated with silver on one surface. PVDF is a ferroelectric polymer that has both pyroelectric and piezoelectric properties. When one side of the cantilever is irradiated by a laser beam, an electric field is produced along cross-section of the cantilever and mechanical displacement occurs by the piezoelectric effect. We measured the response time and the generated force of the cantilever. Optically driven actuator move via the slip-stick effect.
An optical actuator has some interesting characteristics, such as no generation of magnetic noise and receiving the energy remotely. A novel micromanipulator by photothermal effect is proposed. It consists of three optical fiber cantilevers. One end of the fiber is cut for a bevel and painted with black color. A photothermal effect is occurred responding to the incident beam at the end of the optical fiber. It can manipulate a sample and move it in the arbitrary place in 3D space. We succeed to fabricate the 3D structures.
The mechanical characteristics of polymer materials are of interest to the chemical industry. There are requirements for
observation of changes of internal structure to stress. A number of samples under various stress conditions have
provided interesting information upon analysis by microscopic birefringence measurement. In the present paper, we
propose a birefringence measurement method for observation of the internal structure of polymer materials and analysis
of the relationship between a given stress and the corresponding birefringence distribution. The proposed measurement
system consists of a He-Ne laser, polarizers, a half-wave plate and a quarter-wave plate. The birefringence distributions
of gelatin, such as the phase difference and azimuthal angle, are shown for the case of applied uniaxial and biaxial
stress.
A two-dimensional actuator has a feature of a non-contact for applying light energy remotely. It consists of a magnet as a
movement, an acrylic plate and the temperature sensitive ferrite mounted on two-dimensional array on the plate. A curie
temperature of the ferrite is set about room temperature. For moving the magnet, two ferrites in the opposite direction are
irradiated by the laser. The magnetic force decreases by photo-thermal effect. For generating more strong force, a
thickness of the plate and ferrite are optimized by analyzing static magnetic field. As a result, the movement is controlled
in the two-dimensional area. Moreover, we attempt to control magnetic levitation.
We propose a white light displacement sensor using a novel spectro-polarization modulator which generates spiral liner
polarized light sorted along wavelength concentrically. It consists of a polarizer, a retarder with high order retardation,
and a quarter wave plate. If we set the spiral polarizer after the spectro-polarization modulator, we can observe
spectroscopic color concentrically. A displacement measurement method is proposed using chromatic aberration method
and white light interferometer.
We propose a novel spectro-polarization modulator which generates radial liner polarized light sorted along wavelength
concentrically. It consists of a polarizer, a retarder with high order retardation, and a quarter wave plate. If we set the
radial polarizer after the spectro-polarization modulator, we can observe spectroscopic color concentrically. A
displacement measurement method is proposed using chromatic aberration method.
A measurement method for birefringence dispersion is proposed using geometric phase. The optical arrangement consists of a white light source, polarizer, sample, quarter-wave plate, rotating analyzer, such as in a Senarmont setup, and a spectrometer for the visible spectrum from 450 to 750 nm. The experimental setup achieves a phase shift via the geometric phase produced by a cyclic change of polarization state on a Poincaré sphere. We can select four points of geometric phase when the analyzer is set at –45, 0, 45, and 90 deg. It is mathematically demonstrated that these points of geometric phase are independent of wavelength from the calculation of spherical trigonometry drawn on the Poincaré sphere. The phase shifting technique using these four geometric phases is applied to measure birefringence dispersion. Polymer films and optical crystals as samples are experimentally demonstrated, and it is shown that the experimental results agree well with the known quantities of retardation in the visible spectrum.
This paper describes a method and system for the measuring the two-dimensional distribution of birefringence dispersion. An optical arrangement consists of a white light source, parallel polarizers, a CCD camera, and an acousto-optic tunable filter for selecting wavelength of the incident light. The intensity of spectroscopic polarized light changes sinusoidally as a function of wave number, and its period changes slightly because of birefringence dispersion. The fast Fourier transform method is used to analyze the birefringence dispersion from the spectroscopic polarized light. One hundred twenty-eight captured images are used for the analysis. Some experimental results on 2-D birefringence dispersion distributions are shown for the demonstration of this method.
The orientation control of liquid crystal (LC) molecular on the polyimide film has been necessary to fabricate LC devices. Nano-rubbing by atomic force microscope (AFM) has been proposed as the one of methods to control it precisely. In the method, a thin polyimide film was rubbed by a sharpened AFM probe-tip with relatively strong load force. However, the method has some drawbacks; the frictional wear of AFM probe-tip and the difficulty of reorientation after rubbing. In this paper, we have proposed the orientation control of LC on the polyimide film and using direct AFM nano-rubbing method with weak load forces. The change of LC alignment was quantitatively observed by a polarization microscope and birefringence-contrast scanning near-field optical microscope. The effect of scanning density was strong for azimuth angle but the effect of the scanning velocity was weak for both retardation and azimuth angle. An optical switching device was developed utilized isotropic-nematic phase change of liquid crystal which was rubbed in the grating pattern with methyl red dying, and the optical device was operated at the frequency of 0.5Hz. As a result, The proposed method had an effective method to fabricate novel liquid crystal optical devices.
Flat panel displays (FPDs) such as liquid crystal or plasma displays require defect free and highly planer substrate panels in its manufacturing processes. Therefore, it is necessary to remove and analyze a killer dust particle on the panel surface in order to improve a problem and feedback to manufacturing process. However, nanometer-sized dust detection is difficult with an optical microscope and polarized light analysis method because of diffraction limit of light wave. Moreover, a detection method with an electron microscope has a problem, because a detection area is limited. This paper describes a large area detection of nanometer-sized dust on the surface of substrate using an evanescent wave illumination. Samples used in the experiment are polystyrene latex beads with diameter of 10μm, 1μm, and 200nm. A CCD camera observed a light scattering from polystyrene latex beads. The position of polystyrene latex bead could be specified from the scattering light image. This result shows that this method is effective for nanometer-sized dust detection in a large area.
A polarization measurement is proposed to detect a birefringence and an optical rotation distribution in a microscopic area. A residual stress caused by industrial processes and molecular orientation are observed by visualizing birefringence distribution. It is possible to analyze components of material with optical rotation. This measurement system consists of a He-Ne laser, polarizers, a half-wave and a quarter-wave plate. By changing combination of rotating angle of half-wave plate, quarter-wave plate and analyzer, we can obtain retardation, azimuthal angle of birefringence and optical rotation angle independently. An analytical algorithm with local-sampling phase shifting is employed for achieving a high resolution. The errors caused by the initial polarized characteristic of the optical system are corrected by subtracting the in-phase vector.
A varifocus lens by liquid pressure has been developed to change the focal length from a concave to a convex shape by adjusting the liquid pressure. It consists of a polymer film, an acrylic plate, and liquid and it is filled up with the liquid in its cavity. The deformation of the refraction surface of the lens is analyzed theoretically. An experiment by He-Ne laser is performed with a plano-convex type lens. The dynamic range of the focal length of the convex lens is from 50 mm to 250mm. The application for a YAG laser with 1.06μm of wavelength is demonstrated experimentally. The focus was adjusted along the material surface without moving the optical element. As a result, the control of the beam spot diameter is succeeded. Finally, the laser processing is demonstrated to manufacture Fe compressed powder sheets. Its melting marks along a focus change are formed with a minimum width of 100μm.
This paper describes a surface profile measurement using a varifocus lens by an optical sectioning. The focus method is utilized for a uni-axis optical system of projection and observation. The varifocus lens is mounted on between a liquid crystal grating and a projection lens. A focus length can be continuously varied from a concave to a convex shape by changing the liquid pressure. The contrast of projected pattern onto the sample is approximated the Gauss distribution along the distance and indicates sharpest at the focused plane. It is possible to analyze the contrast distribution by a grating projected method using a liquid crystal grating with 4 steps phase-shifting method. The liquid crystal grating is powerful tool to make arbitrary intensity and frequency distribution. Surface profiles of mechanical parts have been measured to demonstrate for this method.
A real-time measurement method for both birefringence dispersion and azimuthal angle is described. An optical set-up of this measurement consists of a white light source, two polarizers and two reterders without any rotation. A spectroscopic intensity is detected by a spectrometer. It is modulated with two different frequencies along wave number. Only the single spectroscopic intensity is sufficient to determine the retardation and the azimuthal angle with wavelength-dependence using two amplitude spectrum and phase by the fast Fourier transform method. A birefringence measurement of a Babinet-Soleil compensator as a sample is demonstrated experimentally.
A super oblique incidence interferometer is proposed by using an anti-reflection prism with sub-wavelength structure. Since the sensitivity of interferogram depends on incident angle it can be achieved lower than ordinary interferometer. A sub-wavelength structure on the prism works an increasing transmittance under the condition of the vicinity of critical angle. A shape of this structure is a triangle with sub-wavelength order of height and width periodically and works matching a difference reflective index between prism and air. The experimental results of transmittance are agreed well with the calculated results by the rigorous coupled wave analysis. Its incident angle of the oblique interferogram can be achieved at 86 degrees. Simulation and experimental results are shown.
An optical actuator has some interesting characteristics, such as no generation of magnetic noise and receiving the energy remotely. A novel two-dimensional actuator using temperature-sensitive ferrite is proposed. It consists of a moving object made by magnet and a base with temperature-sensitive ferrites that are aligned as a matrix. When the temperature-sensitive ferrites are irradiated by the light beam, their magnetic susceptibility is decreased. The moving part moves along opposite side of irradiation light because of balance of magnetic force. The moving effect irradiated by light beam is simulated and measureed. The two dimensional moving of a magnet with 2.4 mm of squire is demonstrated by using 10 x 8 sets of ferrite with 1.5 mm of diameter.
A microscopic birefringence imaging of bio-sample is proposed. This system consists of a super luminescent diode (SLD), polarizers, a quarter-wave plate and a phase retarder. The instrument is provided to map and visualize an optical anisotropy in bio-sample. A local-sampling phase shifting technique is employed for analytic algorithm with high resolution of retardance. A Bereck compensator is used a sample for checking its accuracy. Birefringence distributions of gelatin orientation such as retardance and azimuthal direction are shown in case of applied voltage and changing temperature as its demonstration. It is possible to observe molecular orientation of bio-sample.
A novel birefringence measurement with double rotating polarization elements is proposed. This system includes rotating components of linear polarizer and quarter-wave plate with different rotating speeds. The birefringence is calculated by analyzing the Fourier components for rotation frequency in a detected signal. In this paper, the basic principle and experimental results of the birefringence measurement are described.
A vacuum Mueller matrix polarimeter is developed for measurement of the Mueller matrix of samples, partially, calcium fluoride materials in 157nm wavelength. From the measured Mueller matrix with no sample present, we found the influence of absorption error in the detector and orientation error in quarter-wave plates on measurement results. The birefringence of samples is determined from the Mueller matrix. Experimental results show this Mueller matrix polarimeter is available to be used for characterizing the intrinsic birefringence of materials for processed lens at the 157nm lithography.
An image detection system for vacuum ultra-violet region used a F2 laser (157nm) as a light source is proposed. A fluorescent glass (LUMILASS-G9) is employed to convert UV light into visible light. Characteristics of fluorescent glass are studied. Some beam profiles of F2 laser are analyzed as a demonstration of the imaging detection. A VUV interferometer is proposed.
A laser manipulation technique for metal nanoparticles using an optical fiber has been developed. A micro ball lens adhered onto the flattened end of the optical fiber focuses a light beam propagated through a core. An object is trapped in the focused beam. An electromagnetic field distribution was numerically simulated for validation of the focusing lens. Calculation including an Au nanoparticle indicated that the laser trapping would be possible with this method. In the experiment, trapping of Au particles with diameter of 200nm was achieved by using a light source (Nd-YAG: 1064nm). The maximum trapping efficiency attained in the focal region was estimated to be 5.4fN/mW. Additionally, the fixation of a manipulated particle onto a glass substrate was also demonstrated. With intensifying the laser power, a laser-trapped particle is fixed on the substrate. By repetition of the procedure of laser manipulation and fixation, alignment of Au nanoparticles was achieved.
An optical actuator has some interesting characteristics, such as no generation of magnetic noise and receiving the energy remotely. A novel micromanipulator using photothermal effect is proposed. It consists of three optical fibers. One end of the fiber is cut for a bevel and painted with black color. A photothermal effect is occurred responding to the incident beam at the end of optical fiber. This effect makes the end of fiber stretching vibration. It can release a ball with 2.5 mm of diameter and a microlens currently held by light energy. The mechanism of photothermal vibration is also studied.
A measurement method of birefringence dispersion by geometric phase is described. The measurement system consists of a polarizer, a quarter wave plate, a rotating analyzer and a spectrometer. The detected intensity by a spectrometer changes sinusoidaly along wave number. A phase shifting method is applied to analyze birefringence dispersion. The total amounts of phase change in all of wavelengths are same, because geometric phase produces by cyclic changes of a state of polarization on the Poincaré sphere. The birefringence dispersion of Babinet-Soleil compensator, polymer films and a liquid crystal phase modulator is measured. Compared measured these results with literature values of birefringence dispersion, measured data agrees well. The measurement results shown the birefringence dispersion measurement by geometric phase is available to practical applications.
This paper describes a method and system for two-dimensional measurement of birefringence dispersion with high-order and azimuthal direction. The system consists of a white light source, crossed polarizers and a detector carrying out the spectroscopic polarized light. A spectroscopic interferogram shows sinusoidaly in accordance with wave number change, and its period changes slightly because of dispersion of birefringence. The fast Fourier transform method is used to analyze the birefringence from the spectroscopic interferogram. One hundred and twenty-eight sets of images are used for birefringence analysis. Some results of 2-D birefringence dispersion distribution are shown for the demonstration of this method.
Two evanescent fields were generated on prism surface by incidence of two laser beams from opposite side of the prism at total internal reflection angle. Using photon force of these two evanescent fields, a small particle can be moved backward and forward, and trapped on prism surface. The experimental result shows that a latex sphere of radius 10micrometers can be moved automatically between two points with an error of 9 micrometers . Trapping experiment also shows a clear effect on keeping the position of a small particle against the Brownian motion and flow of water.
This paper describes a method and device for measurement of two-dimensional retardance and dispersion with high-order and azimuthal direction. The system consists of a white light source, crossed polarizers and a detector for spectroscopic polarized light. A spectroscopic interferogram shows sinusoidal to wave number change, and its period changes slightly because of dispersion of birefringence. Fourier transform method is used to analyze the birefringence from the spectroscopic interferogram. One hundred and twenty-eight sets of images are used for birefringence analysis. Some results of 2D birefringence distribution with dispersion are shown for the demonstration.
The paper covers an issue of method and device for measurement of two-dimensional retardance with high-order and azimuthal direction. The system based on the use of a crossed polarizer by changing spectroscopic polarized light. Sixty-four sets of images are used for birefringence analysis. The spectroscopic interferogram change sinusoidal with wave number and the period is in proportion to birefringence of specimen. The measured results of the two dimensional birefringence distribution of a plastic and standard phase plate of retardation are shown. Fourier transform method and maximum entropy method enable to measure birefringence with high resolution. Two examples, measurement of aligned polymer film, which is laminated as steps, and that of birefringence distribution, are demonstrated.
This paper describes a modified birefringence measurement using the scattered light method combined with a phase shifting technique. A phase shift between orthogonal linear polarization components is realized by a retardation compensator. The measured distribution has a periodical error, which can be reduced by a band pass filtering of the Fourier spectrum of scattered light distribution. This method enables a birefringence distribution on a light path to be obtained.
KEYWORDS: Near field scanning optical microscopy, Birefringence, Polarization, Polymers, Near field optics, Signal detection, Optical amplifiers, Linear polarizers, Optical fibers, Photomultipliers
A new optical configuration for a near field scanning optical polarized microscope with an illumination mode is reported. It uses two circularly polarized laser beams with different frequencies which are generated by an axial Zeeman laser. A laser beam is incident on an optical fiber and is launched form the apex of a sharpened fiber probe in order to illuminate the sample. The scattered light on the surface of the sample is collected with an objective lens and goes through the optical elements of the quarter wave plate and the linear polarizer. The light from polarization devices is converted to an electric signal with a photomultiplier and fed into a lock-in amplifier. The quarature components and intensity signal are acquired to computer, and the retardation and the azimuth angle of the birefringence are then calculated via computer. The measurement characteristic of the developed system and image of birefringence material are shown.
A fast and accurate birefringence measurement system has been built to study the in-plane birefringence of a rotating optical disk substrate. The fully automated instrument incorporates an axial Zeeman laser which emits both right and left hand circularly polarized lights, stationary polarization elements and a lock-in amplifier. Measurement results showing the accurate and fast features on the system are presented. It is also demonstrated that the in-plane birefringence mapping in rotating substrate of optical disk can be obtained by use of the ability of fast birefringence measurement.
We present a novel technique to measure both linear and circular birefringence, simultaneously. This technique is based on an optical heterodyne interferometry which is performed by an orthogonally polarized two frequency laser. Two orthogonal components of the optical beat signal are detected by two-phase lock-in amplifier. The two components change sinusoidally with the rotation of azimuth angle of polarization devices. The retardation and the orientation of linear birefringence and the rotation angle of circular birefringence can be calculated by applying a Fourier analysis to the two sinusoidal variations. The measurement sensitivity for this method is verified by using the combination of a Babinet Soleil compensator and a half-wave plate as a sample. It is demonstrated that the birefringence of commercially available twisted nematic liquid crystal cell where a driving voltage is applied can be measured by using the proposed technique.
The phase shifting technique for the measurement of a twodimensional birefringence distribution is described and discussed. The birefringent phase difference and azimuthal angle of a transparent material can be determined in the dependence of both measurements on
the amplitude and phase of the polarization interferometry. A half-wave plate and a Babinet-Soleil compensator are used as phase shifters for the phase shifting technique. It can measure 256 x 256 values of the birefringent phase difference and azimuthal angle in a short time with sufficient accuracy. This method does not require moving the sample mechanically. The results and procedures for measuring such a birefringence distribution of optical components such as a calibrated Babinet-Soleil compensator, a lens, and a roof prism are discussed.
We propose a two-dimensional birefringence measurement method. A linearly polarized light goes through a Babinet-Soleil compensator whose principle axis direction is set 45 degree to the incident light. The light is affected by the birefringence when it passes through an optical sample. The interference fringe behind a linear polarizer is captured wholly as a two- dimensional image by a CCD camera. The data is analyzed into the phase information by the phase shifting technique using a Babinet-Soleil compensator. Here the obtained phase changes sinusoidally. Its amplitude and phase mean the relative retardation and azimuth angle respectively when a polarization azimuth of the incident light is rotated. A half-wave plate as a phase shifter is used again to obtain this amplitude and phase using the phase shifting technique again. We discuss these experimental procedures and results applied to such optical components as a lens and a roof prism.
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