Showing papers on "Total internal reflection published in 1977"
TL;DR: In this article, the angular distribution of the power radiated by magnetic or electric dipoles located at distance z 0 from a dielectric interface and oriented perpendicular to it is derived.
Abstract: We have derived analytical expressions for the angular distribution P(α) of the power radiated by magnetic or electric dipoles located at distance z0 from a dielectric interface and oriented perpendicular to it. For dipoles in the rarer medium very close to the interface, evanescent waves in the dipoles’ near field give rise to strong radiation into the denser medium. The resulting large maximum of P(α) shows characteristic differences for magnetic and electric dipoles when the relative refractive index of the two dielectrics is greater than √2. For dipoles lying on the interface a symmetry relation is established connecting the power distributions P(α) for the values n and 1/n of the relative refractive index.
270 citations
TL;DR: In this article, the angular spectrum representation of the reflection of a beam of light at a plane interface is treated using angular spectrum representations, and the Goos-Hanchen shift is found to be proportional to the first derivative of the phase of the reflectance, which gives rise to a shift of the reflected beam along its direction of propagation.
Abstract: The reflection of a beam of light at a plane interface is treated using the angular spectrum representation. The Goos-Hanchen shift is found to be proportional to the first derivative of the phase of the reflectance. The second derivative of the phase gives rise to a shift of the reflected beam along its direction of propagation. This new shift, called a focal shift, is different from the extra propagation distance of the beam predicted on the basis of a ray model for total internal reflection. Expressions are presented for the Goos-Hanchen and focal shifts for both s and p polarization.
150 citations
TL;DR: In this paper, the behavior of a Gaussian ultrasonic beam incident on a liquid-solid interface at the Rayleigh angle has been studied in some detail, and good agreement is obtained between experimental results and the theory of Bertoni and Tamir.
Abstract: The behavior of a Gaussian ultrasonic beam incident on a liquid‐solid interface at the Rayleigh angle, the angle at which surface waves are excited on the interface, has been studied in some detail. The reflected beam is displaced in the manner predicted by Schoch; however, the ’’Schoch displacement’’ in general is too large. Good agreement is obtained between experimental results and the theory of Bertoni and Tamir, which assumes that the incident beam couples resonantly into a leaky surface wave at the Rayleigh angle and that the energy reradiated from this leaky surface wave interferes with specularly reflected energy. The propagation distance of the ultrasonic beam is explicitly included in describing the ultrasonic wave reflection at the Rayleigh angle.
109 citations
TL;DR: In this article, a paraffin prism was used to measure the longitudinal and transverse shifts of an 8 cm parallel bounded beam of 34.2 GHz (8.77 mm) microwaves.
Abstract: Longitudinal and transverse shifts of an 8 cm parallel bounded beam of 34.2 GHz (8.77 mm) microwaves totally reflected from a paraffin prism have been investigated. The 45°–45°–90° prism is 18 cm high by 25 cm on the sides and the index of refraction is 1.491. Longitudinal shifts as large as 3 cm have been measured in a single reflection near the critical angle for a beam linearly polarized in the plane of incidence. The shift for perpendicular polarization is approximately half this value. The results are in general agreement with the classical theory for the Goos-Hanchen effect. An incident beam polarized at 45° to the incidence plane produces both parallel and perpendicular polarization shifts with values similar to the above. The shifts for both polarizations are reduced but are still distinctly separate if either a second prism or a metallic reflector is brought into the evanescent wave at millimeter distances from the interface. These results are in accordance with stationary phase calculations for two interfaces. It is found that a small (6 mm) transverse shift results if the prism is illuminated with circularly polarized microwaves.
84 citations
TL;DR: In this paper, the reflectance of planar targets irradiated by 400mJ, 30-ps Nd: glass laser pulses was measured as a function of angle of incidence and polarization with an Ulbricht spherical photometer.
Abstract: The reflectance of planar targets irradiated by 400-mJ, 30-ps Nd: glass laser pulses was measured as a function of angle of incidence and polarization with an Ulbricht spherical photometer. At normal incidence we find reflectances >0.6. The reflectance for p-polarized light has a minimum at an incidence angle 20/sup 0/ to 30/sup 0/; for angles greater than 60/sup 0/ total reflection occurs for both s- and p-polarized light. The results seem consistent with simulations.
53 citations
TL;DR: In this article, the authors propose to deconvolute a set of spectra taken at different angles into spectra corresponding to successive depth invervals, which is done by a new technique that measures spectra twice at each angle with different prism materials to give the necessary data sets.
Abstract: In total reflection spectroscopy the effective sampled depth increases as the angle of incidence approaches the critical one. At each angle of incidence, successive layers within the sample are weighed differently in the overall spectrum, and the manner of this weighing changes with angle. It is thus possible in principle to deconvolute a set of spectra taken at different angles into spectra corresponding to successive depth invervals. As this angular effect is particularly marked near the critical angle, where attenuated total reflection spectra are severely distorted, the spectra usually require inversion into optical constant spectra. This has been done by a new technique that measures spectra twice at each angle with different prism materials to give the necessary data sets. Examples of such subsurface spectra are shown.
44 citations
TL;DR: In this article, an improved reflective wall for radiant energy collection and concentration devices is provided, which is comprised of a plurality of prisms whose frontal faces are adjacent and which reflect the desired radiation by total internal reflection.
39 citations
TL;DR: When a Gaussian beam of finite width is partially reflected at a planar dielectric interface, there is in general a shift in the reflected beam direction away from that predicted by the simple application of the geometrical optics relfection law as discussed by the authors.
Abstract: When a beam of finite width is partially reflected at a planar dielectric interface, there is in general a shift in the reflected beam direction away from that predicted by the simple application of the geometrical optics relfection law. We give a simple derivation of this shift, clarifying the underlying physical mechanism. The Gaussian beam is studied in detail.
35 citations
TL;DR: In this paper, a very strong amplification of both the longitudinal and the transverse shifts in total reflection of a light beam, rendering them easily observable, together with the filtering of the corresponding pair of polarization eigenmodes, has been obtained by using one single reflection at a multilayered interface.
Abstract: A very strong amplification of both the longitudinal and the transverse shifts in total reflection of a light beam, rendering them easily observable, together with the filtering of the corresponding pair of polarization eigenmodes, has been obtained by using one single reflection at a multilayered interface. After presenting the general philosophy of this approach and summarizing the computational techniques used by one of us (Y. Levy), we describe the two experimental setups, and produce the photographic recording of our results. Some theoretical implications of these are very briefly discussed in our conclusion.
32 citations
TL;DR: In this paper, it was shown that the predicted focal shift associated with total internal reflection follows from the ray model of the Goos-Hanchen shift if the variation of the GOH with angle is taken into account.
Abstract: The recently predicted focal shift associated with total internal reflection is shown to follow from the ray model of the Goos-Hanchen shift if the variation of the Goos-Hanchen shift with angle is taken into account.
31 citations
TL;DR: In this article, the authors deal with the phenomenon of reflection of plane elastic waves in a free surface when the medium is initially stressed and show that the reflected P and SV waves depend on initial stresses present in the medium.
Abstract: The paper deals with the phenomenon of reflection of plane elastic waves in a free surface when the medium is initially stressed. It has been shown analytically that the reflected P and SV waves depend on initial stresses present in the medium. The numerical values of reflection coefficients for different initial stresses and the angle of incidence have been calculated by the Computer I.C.L. 1901-A and the results are given in the form of graphs. Many interesting results are found in the paper which are not seen in an initially stress-free medium.
TL;DR: In this article, it was shown that the intensity of the electronic current backscattered from the surface is the convolution product of the total reflection coefficient by the energy distribution of the incident beam.
Abstract: It is shown that the intensity of the electronic current backscattered from the surface is the convolution product of the total reflection coefficient by the energy distribution of the incident beam. A deconvolution method has been used to obtain this coefficient and this method is based on a rigorous inversion of the convolution integral operator. Numerical tests show that this method is not very sensitive to the experimental random noise. Results are given for W(100), Cu(100), and O/Cu(100) surfaces, and these are correlated with earlier measurements.
TL;DR: In this paper, the reflectance from an amplifying region in which the gain decreases exponentially with distance from the surface is calculated as a function of incident angle, and the results for the exponential case do not explain the previously reported observation of large reflection from a pumped laser dye.
Abstract: The reflectance from an amplifying region in which the gain decreases exponentially with distance from the surface is calculated as a function of incident angle. The results are similar in some respects to the reflectance from a uniform amplifying layer reported previously. In particular, a singular point occurs in the reflectance for certain values of the thickness of the amplifying region. However, the results for the exponential case do not explain the previously reported observation of large reflectance from a pumped laser dye. An asymptotic form of the reflectance for a thick amplifying region is presented. The results for asymptotic case are compared with various other theories of reflection from an amplifying region.
Patent•
11 Nov 1977
TL;DR: In this article, a method and apparatus for switching an infrared radiation signal laser beam in which a semiconductor, capable of transmitting the signal beam without damage, is provided and upon which a signal beam is incident at an angle which may preferably be Brewster's angle.
Abstract: A method and apparatus for switching an infrared radiation signal laser beam in which a semiconductor, capable of transmitting the signal beam without damage, is provided and upon which the signal beam is incident at an angle which may preferably be Brewster's angle. The surface of the semiconductor is irradiated by a second laser beam which has a sufficiently high frequency to produce free carriers in the semiconductor and which has a sufficient radiation intensity and time duration to produce a free carrier density greater than the critical density for the signal beam resulting in substantially total reflection of the signal beam from the semiconductor surface. In particular, a pulsed CO 2 laser beam which is incident on a polycrystalline n-type germanium semiconductor is reflected by irradiating the semiconductor with a pulsed ruby or Nd:glass laser beam.
TL;DR: Using a cw dye laser beam normally incident on a glass-Na-vapor interface, fluorescence excitation spectra of the ${D}_{1}$ line are measured as mentioned in this paper.
Abstract: Using a cw dye laser beam normally incident on a glass-Na-vapor interface, fluorescence excitation spectra of the ${D}_{1}$ line are measured. By observing the fluorescence transmitted into the glass above the angle of total reflection, only evanescent light emitted within about a wavelength distance from the interface is observed. The measured spectra show a cutoff on the high-frequency side which is direct evidence for the transient behavior of the induced polarization of resonantly excited vapor atoms which have collided at the solid interface.
TL;DR: In this paper, the limitations inherent in the interpretation of the reflected field are described, including the dependence of the measurement on the complete geometry of the experiment, the occurrence of negative bottom loss and the apparent shift in the critical angle.
Abstract: The determination of the acoustical properties of the ocean bottom is a formidable task. One method is the seismic reflection method. Some of the limitations inherent in the interpretation of the reflected field are described. These include the dependence of the measurement on the complete geometry of the experiment, the occurrence of negative bottom loss and the apparent shift in the critical angle.
Patent•
14 Mar 1977
TL;DR: In this article, an apparatus including a frusto-conically shaped tube for transmitting light with internal reflection surfaces which diverge in the direction from input to output is described. But this apparatus is not suitable for distance measuring instruments in which the output of the tube is directed to an object.
Abstract: An apparatus including a frusto-conically shaped tube for transmitting light with internal reflection surfaces which diverge in the direction from input to output. Incident light from an LED or other substantially phase coherent source is mixed by internal reflection of rays incident at greater than a predetermined angle to minimize the non-uniform phase front and concentrate the beam to permit greater transmitted power. The apparatus finds particular utility in distance measuring instruments in which the output of the tube is directed to an object and the phase of the reflected light compared with the phase of the transmitted light to determine the distance.
29 Aug 1977
TL;DR: In this paper, the quantum efficiency of microchannel plates has been measured at energies from 0.28 to 3.0 keV and at angles less than 6°, with an energy of 0.86 keV.
Abstract: The quantum efficiency of microchannel plates has been measured at energies from 0.28 to 3.0 keV and at angles less than 6°. The quantum efficiency reaches a maximum of 27% at 3° and an energy of 0.86 keV. At all energies, the quantum efficiency increases as the angle of incidence decreases until a critical angle is reached, after which the efficiency decreases rapidly. The quantum efficiency, outside of the small angle dip, decreases with energy at a constant angle. The general behaviour of the quantum efficiency can be understood using a very simple physical model. The low angle dip is caused by reflection from the surface of the channel. The variation of the quantum efficiency as a function of energy can be explained by the variation of the X-ray absorption and of the photo- and Auger electron ranges. The data are reasonably reproduced by a simple model.
TL;DR: In this paper, a perturbational approach, similar to the earlier treatments but applicable to oblique incidence and to all perturbation orders, is presented, and the first-order reflection coefficient of a Rayleigh wave from an inclined groove is computed.
Abstract: Several theoretical treatments now exist in the literature for scattering of Rayleigh waves from topograhic features which are parallel to the incident wave front. These treatments, however, are not applicable to a large class of signal‐processing devices in which the surface waves are scattered by inclined reflectors. A perturbational approach, similar to the earlier treatments but applicable to oblique incidence and to all perturbation orders, is presented. The first‐order reflection coefficient of a Rayleigh wave from an inclined groove is computed. It is shown that an angle similar to a ’’Brewster’’ angle exists for which the surface wave reflection coefficient is zero. A prescription for applying the theory to anisotropic media is suggested. A clarification of the applicability of this and prior theories to steep‐walled structures is given.
TL;DR: An exact expression for the pseudo-Brewster angle and some relatively easy-to-use formulas giving an approximate value for this angle and for the minimum value of the vertical polarization reflection coefficient are presented in this paper.
Abstract: An exact expression for the pseudo-Brewster angle, and also some relatively easy-to-use formulas giving an approximate value for this angle and for the minimum value of the vertical polarization reflection coefficient are presented.
TL;DR: In this paper, the Lloyd's mirror was analyzed for the case of total internal reflection and the reflected wave was interpreted in terms of the Goos-Hanchen shift, and the interference between the incident and reflected beams provided an interferometric method of measuring the GSH at grazing incidence.
Abstract: Lloyd’s mirror is analyzed for the case of total internal reflection. The reflected wave is interpreted in terms of the Goos-Hanchen shift. The interference between the incident and reflected beams provides an interferometric method of measuring the Goos-Hanchen shift at grazing incidence. An experiment is described and the results presented. The results agree with those theories which predict a nonzero shift at grazing incidence. The lateral wave is observed in the experiment.
Patent•
07 Dec 1977TL;DR: In this paper, an internal reflectance spectrometer comprising a prism adaptable for optically coupling test sample to one surface of a surface of interest is presented. And the instrument of the present invention is a full range absorbtion spectrometers.
Abstract: The present invention encompasses an internal reflectance spectrometer comprising: (a) a prism adaptable for optically coupling test sample to one surface thereof; (b) a means for irradiating the test sample with light of wave length absorbed by the test sample, said means directing light to enter the test sample from the prism surface having test sample thereon at an angle between the critical angle and about 35° less than the critical angle, said light refracted in the test samples so that said light is internally reflected from the test sample remote from the prism surface; and (c) a means for detecting the internally reflected light. The instrument of the present invention is a full range absorbtion spectrometer.
TL;DR: In this article, a new holographic selector, operating on the basis of total internal reflection, is described, which has a higher angular dispersion than the devices available at present and this is combined with lower losses inside a laser resonator.
Abstract: A new holographic selector, operating on the basis of total internal reflection, is described. An analysis shows that this selector has a higher angular dispersion than the devices available at present and this is combined with lower losses inside a laser resonator. A method is given for the calculation of the parameters of a selector operating in the range of wavelengths (0.2–1.2μ) emitted from tunable lasers. This selector uses holographic volume phase gratings recorded in dichromated gelatin films whose optical strength is 2–4 J/cm2 at λ = 1.06μ for pulses of τp = 10 nsec duration. Frequency selection and wideband tuning are reported for a neodymium-glass laser. The width of the spectrum does not exceed 0.7cm–1 in the spiky regime. Single-frequency emission, tunable in a range exceeding 200cm–1, can be obtained in the Q -switched regime (switching by a passive shutter).
TL;DR: In this article, the results of wide angle X-ray diffraction and, ATR polarization measurements are reported in order to characterize the anisotropy in poly(m-phenyleneisophthalamide) and poly(p-phenyleneterephthalamide) (Fiber B) fibers.
Abstract: The results of wide angle X-ray diffraction and, ATR polarization measurements are reported in order to characterize the anisotropy in poly(m-phenyleneisophthalamide) and poly(p-phenyleneterephthalamide) (Fiber B) fibers. Additional information on the state of order of the investigated fibers is derived from ATR spectroscopic accessibility measurements by deuterium exchange.
TL;DR: In this article, a generalized Wentzel-Kramer-Brillouin (WKB) approach is used to obtain full wave solutions for horizontally polarized waves in inhomogeneous media when no closed form analytic solutions are known.
Abstract: A generalized Wentzel-Kramer-Brillouin (WKB) approach is used to obtain full wave solutions for horizontally polarized waves in inhomogeneous media when no closed form analytic solutions are known. This approach is suitable for complex permittivity profiles with critical coupling regions even when the permittivity gradient approaches zero. The transmission and reflection coefficients and the characteristic surface impedance for inhomogeneous layers of finite thickness are computed for several permittivity profiles. Excitation of propagating and evanescent waves is considered and the results are shown to satisfy the realizability and reciprocity relationships in electromagnetic theory. Sinusoidal permittivity profiles for which closed form analytical solutions are known are also considered to provide an additonal check on the generalized WKB solutions. For permittivity profiles with several spatial periods, transmission windows with very narrow beamwidths are found to exist. When conditions for total internal reflection in the inhomogeneous dielectric layer are satisfied, the reciprocal of the reflection coefficient vanishes and propagating waves are trapped in the layer. For these trapped waveguide modes the inhomogeneous dielectric is characterized by a surface reactance.
Patent•
04 Aug 1977TL;DR: In this article, a fire detector comprises a Fresnel lens (1) with two foci, one side of the workpiece, the radiation source (4) being disposed on a home and the beam detector (5) on the other.
Abstract: Detector optics lamp in which a radiation source (4) produces a light beam which, after crossing the air in a room is captured by a detector (5) for determining whether the characteristic properties (intensity, modulation) of received ray have been modified as a result of combustion, which produces an aerosol or convection in the air. The fire detector comprises a Fresnel lens (1) has two foci, one side of the workpiece, the radiation source (4) being disposed on a home and the beam detector (5) on the other. On the other side of the workpiece is arranged a reflector (6) which reflects by total internal reflection the beam projected through the Fresnel lens (1). A display circuit (11) connected to the detector of radiation (5) indicates that the variation of the characteristics values of the emitted beam and received exceeds a threshold value.
Patent•
12 Dec 1977TL;DR: A light conducting rod as discussed by the authors is a rod in which light incident on the surface of the rod is conducted along the rod to its end faces for subsequent detection, where the light entering the rod was incident on three neighboring linear arrays of individual mirrors formed along the diametrically opposite surface of a rod.
Abstract: A light conducting rod in which light incident on the surface of the rod is conducted along the rod to its end faces for subsequent detection. The light entering the rod is incident on three neighboring linear arrays of individual mirrors formed along the diametrically opposite surface of the rod; each individual mirror is inclined towards the axis of the rod and cylindrically curved so that the light is reflected back onto the internal surface of the rod at an angle which ensures total internal reflection.
Patent•
27 Dec 1977TL;DR: In this article, light is efficiently coupled from a laser into a dielectric optical wave guide without the use of additional optical components using an oscillating mode using total internal reflection within the laser element, one face of the element intimately contacting a wave guide light output coupling wall.
Abstract: Light is efficiently coupled from a laser into a dielectric optical wave guide without the use of additional optical components. An oscillating mode using total internal reflection within the laser element is employed, one face of the element intimately contacting a wave guide light output coupling wall.
TL;DR: In this article, the interference effects normal to the plane of incidence were calculated for a light beam incident on a reflecting surface consisting of several parallel thin layers, and the results were compared with Levy and Imbert's recent experiment.
Abstract: Interference effects normal to the plane of incidence are calculated for a light beam incident on a reflecting surface consisting of several parallel thin layers. Resonances that arise when one of the thin layers acts as a two-dimensional waveguide give rise to phase shifts of the plane waves in the reflected beam which vary rapidly with the angle of incidence. Interference in the reflected beam can then sometimes give it the appearance of a diffraction pattern. The results are compared with Levy and Imbert’s recent experiment.
TL;DR: In this article, a beam splitter based on frustrated total reflection was proposed, which depends on a slow variation of guide thickness that permits the existence of an evanescent wave by which light is transferred from one side of the beam splitters to the other.
Abstract: A simple thin-film beam splitter has been made by sputtering techniques. The device is similar in principle to beam splitters in bulk optics based on frustrated total reflection. It depends on a slow variation of guide thickness that permits the existence of an evanescent wave by which light is transferred from one side of the beam splitter to the other. The tunneling region has a variable index profile and there are no discontinuities. Fabrication techniques, theory, and experimental results are presented.