Fast axis

Relative to specimens examined under the microscope, the a or fast axis corresponds to the direction of the minimum refractive index, the minimum dielectric constant, and the maximum velocity. The y or slow axis corresponds to the maximum refractive index, the maximum dielectric constant, and the minimum velocity. Occasionally, a (3 axis is recognized with intermediate properties between a and y. When working with elongated bireffingent structures, birefringence usually is taken as positive when the y axis is parallel to the longitudinal axis. 

Figure 4.11 Two optical retarders. F fast axis, S slow axis. In both cases the incident beam is polarized under 45°. Left a quarter wave plate retards the slow component of the polarization by 7t/2 and elliptical polarization is achieved. Right a half-wave plate rotates the plane of polarization from 45° to -45°.

The time resolved rotation and ellipticity signals acquired for different orientations of the pump quarter wave plate are shown in Figures 4 and 5, respectively, for different metals. As expected from equation (1), the signals consist of two components varying with periods of 90° and 180° with respect to the angle tp between the fast axis of the pump quarter wave plate and the plane of incidence. The SOKE contribution has period of 90° and... 

Figure 1. Schematic diagrams of TEB and LLS instrumentation. P, pinholes L, lenses B, polarizers C, cell Q, quarter wave plate PMT, photomultiplier tube HVG, high voltage generator MP, microprocessor TR, transient recorder CL, correlator CT, counter 6, scattering angle. For the TEB setup polarizers B-, B2 have polarization axis oriented at tt/4 with respect to the x-axis, as shown in (a). After the light beam passed through the cell with electric field in the x-direction containing a suspension of anisotropic particles and the quarter waveplate with its fast axis oriented at tt/4 with respect to the x-axis, the transmitted light beam is polarized in the direction of 71/4 + 6/2, as shown in (b). Analyzer B has polarization axis oriented at 3t/4 + a as shown in (c).

Polarization modulation The cross section of the optical fiber has a fast axis and a slow axis that are mutually perpendicular. Two light waves individually polarized about each of these axes will not usually interfere with each other and their intensity can be separately measured using polarizing filters. External stimuli such as pressure or twisting of the fiber may induce transfer between the two polarized modes, which may be quantified and used for measurement. 

Figure 18.14(a) shows a schematic of the electrostatically driven mirror with two directions of deflection. The fast moving mirror is fixed by torsion springs at a gimbal and is excited to oscUlate by an electrostatic drive, realized by stacked comb electrodes. The gimbal itself is also fixed by torsion springs to the MEMS chip and is excited to oscillate more slowly to perform the vertical sweep. In one of the test designs realized in the author s lab, the mirror has a diameter of 0.9 mm and oscillates in resonance with 32 kHz as fast axis frequency and with 0.6 kHz as slow axis frequency. 

Scan test Each cell is written, or read, sequentially. The addressing sequence can count up fi om the minimum address (minmax) or down from the maximum address (maxmin). Either the XOT y axis can be the fast axis (rowfast or columnfast, respectively). 

A CT+-wave passes through a A/2-wave plate with its fast axis in y-direction. The transmitted light is then... 

A A/2-plate with its fast axis in the x-direction is rotated by an angle 9 around the z-axis (direction of light propagation). If linear horizontal polarized light passes through the device the output light is... 

The setting of the optical components is defined by the angles P, A and C of its distinct axis, with respect to the plane of incidence. An angle C = —45 means the fast axis of the compensator is set to an angle of —45° with respect to the plane of incidence. 

Rotational diffusion abont the fast axis is on a time scale of a few tens of picoseconds, while rotation abont the slow axes is still on a subnanosecond time scale in water, and on a time scale of a few nanoseconds in mixtures of water with organic solvents The spectra can be simulated nearly perfectly without assuming... 

The propagation of coherent light through such a birefringent material with this retardation can be expressed as a Jones matrix, assuming that the fast axis is parallel to the y axis... 

It is more useful to be able to express the retardation from an arbitrary rotation of the fast axis by an angle y/ about the y axis. Rotation with Jones matrices can be done as with normal matrix rotation. If we define a counter-clockwise rotation of angle Y about the y axis as positive, then the rotation ma-... 

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