Rotation Angle Of Plane Research Articles

A type of electro-optic Q-switch designed by using optically active crystal

A type of electro-optic Q-switch is designed by using optically active crystal La3Ga5SiO14 (abbreviated as LGS), in which the polarization plane gyration and electro-optic effect exist simultaneously. The configuration of the Q-switch is based on the consideration that the total rotation angle of the polarization plane of the polarized laser is zero, while the laser in the cavity propagates through the Pockels cell back and forth. The Q-switch placed in a Nd3 +:YAG laser behaves normally, like those without optical activity. Compared with the DKDP Q-switch, the LGS Q-switch has more superiorities, which make it a suitable replacement for the DKDP Q-switch in lasers with medium-output energy.

Laser pumping and magneto-optical rotation of the light polarization plane in a cell with an antirelaxation coating of the walls: II. Calculation for atoms with the Λ scheme of sublevels

The general solution of the Boltzmann kinetic equations obtained previously by the author for the atomic density matrix in a long cylindrical cell with an antirelaxation coating of the walls under conditions of laser pumping in a magnetic field is used for the calculation of the magneto-optical rotation of the light polarization plane. It is shown that, in accordance with experimental data, the dependence of the rotation angle of the polarization plane of the pumping light on a magnetic field ranging from −1 to 1 Oe represents a sum of two antisymmetric curves: a narrow curve with a spacing between extrema of about 2 μOe and a broad curve with a spacing of about 0.03 Oe. It is found that the characteristics (the width and the amplitude) of these two curves depend quite differently on the parameters of the problem—the pumping power, the coating Q factor, the pumping beam radius, and the cell radius. This difference is explained by the fact that the two curves are associated with different physical processes: the narrow curve characterizes the distortion caused by the magnetic field in the atomic polarization accumulated during multiple passages through the pumping beam after almost nondepolarizing collisions with the coating, while the broad curve corresponds to the distortion of the polarization formed during a single passage through the beam.

Estimation of rotation and slant angles of a textured plane using spectral moments

AbstractThis paper proposes a method for estimating rotation and slant angles with slant direction of a textured plane using spectral moments. When a textured plane rotates and slants, the 2D power spectrum also rotates and expands toward the slant direction. Thus, the spectral moments also change corresponding to the rotation and expansion. The rotation angle, slant angle, and slant direction of a textured plane can be derived from the comparison between the second‐order spectral moments of a standard image and those of a test image. We show the validity of the method in simulations using the synthesized images and in experiments using real images taken with a CCD camera. © 2003 Wiley Periodicals, Inc. Syst Comp Jpn, 34(6): 21–31, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10314

35 Cl NQR Studies of the Geometry of Aromatic Imines

The preferred conformation of solid‐phase R‐4‐benzylidene‐3,4‐dichloroaniline molecules has been established by nuclear quadrupole resonance (NQR) combined with quantum chemical calculations. The conformational effect of substitutes reported previously is proved. The rotation angle of the plane of the aniline ring with respect to the plane of the azomethine bond is given.

ATLANTOAXIAL INSTABILITY IN OS ODONTOIDEUM WITH MYELOPATHY

Study design This study analyzed the correlation between the atlantoaxial instability (especially sagittal plane rotatory instability) and myelopathy. Thirty-four patients with os odontoideum were reviewed in clinical symptoms and radiographs. Objectives The results were correlated to provide a rationale for the genesis of myelopathy. Summary of background data Instability of the atlantoaxial joint has been evaluated with atlantodental interval, space available for the spinal cord, instability index, and others. These are excellent indices for anteroposterior instability. However, they are insufficient for the evaluation of the multidirectional instability in os odontoideum. Methods Thirty-four patients were analyzed in three parameters on the lateral radiographs: the minimum distance from the posterior border of the C2 body to the posterior arch of atlas, the difference of the atlanto-axial angle between the flexion and extension position (sagittal plane rotation angle), and the change of space available for the spinal cord from flexion to extension (Instability Index). Results The correlation between the sagittal plane rotation angle and the instability index was low (r = 0.561). In patients with more than 20 degrees of the sagittal plane rotation angle, myelopathy was shown at a high rate (86%). Myelopathy was also shown at a high rate (90%) in the patients with more than 40% of the instability index. Conclusions It is important to check the sagittal plane rotation angle and the instability index to evaluate the instability in os odontoideum. If the patient has either a sagittal plane rotation angle of more than 20 degrees or an instability index of more than 40%, he or she is likely to have the cord signs.

Faraday–Stark optoelectronic effect

An optoelectronic effect based on Faraday or Kerr rotation and the quantum-confined Stark shift is demonstrated. It is novel in that the degree of rotation is controlled by an electric field as opposed to a magnetic field. By applying an electric field to a quantum well structure, the Faraday rotation can be tuned into resonance, thereby varying the rotation angle of plane polarized light. We have observed a resonant rotation of 10° in GaAs at a magnetic field of 1 T. By applying a gate voltage of 2 V to a GaAs/AlGaAs superlattice structure, we observed a change in rotation of 1.3° at 2 K. The Faraday–Stark effect could be useful in electrically controlled light switches and high-speed optical modulators.

Atlantoaxial instability in os odontoideum with myelopathy.

This study analyzed the correlation between the atlantoaxial instability (especially sagittal plane rotatory instability) and myelopathy. Thirty-four patients with os odontoideum were reviewed in clinical symptoms and radiographs. The results were correlated to provide a rationale for the genesis of myelopathy. Instability of the atlantoaxial joint has been evaluated with atlantodental interval, space available for the spinal cord, instability index, and others. These are excellent indices for anteroposterior instability. However, they are insufficient for the evaluation of the multidirectional instability in os odontoideum. Thirty-four patients were analyzed in three parameters on the lateral radiographs: the minimum distance from the posterior border of the C2 body to the posterior arch of atlas, the difference of the atlanto-axial angle between the flexion and extension position (sagittal plane rotation angle), and the change of space available for the spinal cord from flexion to extension (Instability Index). The correlation between the sagittal plane rotation angle and the instability index was low (r = 0.561). In patients with more than 20 degrees of the sagittal plane rotation angle, myelopathy was shown at a high rate (86%). Myelopathy was also shown at a high rate (90%) in the patients with more than 40% of the instability index. It is important to check the sagittal plane rotation angle and the instability index to evaluate the instability in os odontoideum. If the patient has either a sagittal plane rotation angle of more than 20 degrees or an instability index of more than 40%, he or she is likely to have the cord signs.

レーザ光平面による位置計測法 (第1報)

A new measuring method is proposed for estimation of robot positioning accuracy. The principle of the method is that one point in 3-dimensional space can be regarded as an intersecting point of three intersecting planes. The coordinates of it can be obtained by solving simultaneous equations of the three planes. According to the principle, a system consisting of a laser detector on the target point, two horizontal scanners, one vertical scanner and a computer has been developed. Each scanner is used to rotate the linearly spread laser beam called laser plane. The rotation angle of the laser plane can be measured with high resolution (0.26'') by using rotary-encoder and time-conversion method. Laser detector is set at each target point. When the laser plane is detected by the detector during scanning for each scanner, the rotated angle of the plane is measured to give equation of one of three intersecting planes. Finally, the coordinates of target point can be obtained by solving equations of the three laser planes determined above. Experimental results show that the 1-dimensional measuring accuracy is ±30 μm and the standard deviation of it is 10μm within a range of 1 m at the distance of 2 m from the scanner.

Magnetic field rotation of a strong resonance radiation polarization plane in the media with Doppler-broadened transitions of 01 and 10 types

For atomic media with resonant Doppler-broadened transitions of J=0 to J'=1 or J=1 to J'=0 type and taking into account the relaxation due to depolarizing collisions a theory of nonlinear magneto-optic polarization phenomena is developed. The theory is valid in the case of both arbitrary resonance linearly-polarized radiation intensity and arbitrary external magnetic field spatial orientation. The Faraday and Voigt geometries are analysed in detail, and in the case of the Faraday geometry the effect is considered of a noncompensated magnetic field transverse component on the shape of a dependence relating the radiation polarization plane rotation angle to a magnetic field longitudinal component. In the case of the Voigt geometry an essential effect is found of the angle between the radiation initial polarization and transverse magnetic field vectors on the character of the dependence relating the radiation polarization plane rotation angle to the transverse magnetic field magnitude.