Rotating half-wave plate

Schematic diagram showing the integration of a polarization modulated birefringence apparatus within a laser Doppler velocimeter. This shows the side view. L light source (a diode laser was used) PSG rotating half-wave plate design LS lens FC flow cell (flow is into the plane of the figure) CP circular polarizer D detector 2D-T two dimensional translation stage 3D-T three dimensional translation stage LDVP laser Doppler velocimeter probe.

Figure 14. Experimental apparatus for picosecond, time-resolved CD measurements using a mode-locked, Q-switched, cavity dumped pump laser. P, polarizer PC, Pockels cell Q, quarter-wave plate RHP, rotating half-wave plate S, sample cell PMT, photomultiplier tube. From ref. [42].

Cao XL, Dukor RK, Nafie LA (2008) Reduction of linear birefringence in vibrational circular dichroism measurement use of a rotating half-wave plate. Theor Chem Acc 119 69-79... 

If ion lasers are already available in the laboratory, a different method for controlling their intensity with a compnter is needed. One simple and cost-effective method is to use a graded neutral density filter than can be moved with a computer-controlled motorized stage, or alternatively, a combination of a rotating half-wave plate and polarizers. A more expensive, but versatile option is an electroaconstic modulator, but none of these alternatives will be described here. 

We constructed a liquid nitrogen cooled infrared camera (PICNIC), whidi uses a NICM0S3 256 X 256 format array detector and a new optical syst which consists of reflective optics (Fig. 1). Two additional componoits, a rotating half wave plate polarimeter and a prism, can be attadied in front of the camera, enabling us to obtain imaging polarimetry and multi-object spectroscopy. 

For such a scheme, the overall adiabatic evolution is possible if individual rotation angles rotated smoothly and if there are a sufficient number of layers. It is necessary that each of the birefringent crystals drives no more than a fraction of a Rabi cycle in that segment, in other words if each segment is a fraction of a half-wave plate. 

Consider a sequence of A half-wave plates, each rotated by angle with respect to the chosen Cartesian coordinate system. Specifically, we propose angles... 

When circularly polarized light falls on a quartz half-wave plate in the shape of a disc, a torque is developed. The transmitted light is of the opposite circular polarization. The half-wave plate disc can rotate as it hangs on a thin quartz fibre, and the magnitude of the photon spin can be deduced from the torsion angle a. 

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°.

Half-wave plates are used to rotate the electric vector of light. Incident light with its polarization vector oriented at an angle 0 relative to the principal axes of n has an elec-T... 

Figure 2.5 The rotation of linearly polarized light using a half-wave plate.

Half wave plates are used to rotate the principal axis of the polarization ellipse (see section 2.4.2). Half wave plates for applications involving single wavelengths can be fabricated in precisely the same manner as quarter wave plates, but with thicknesses that are twice those specified by equation (9.1). 

The excitation of the t-PL was carried out using a continuous wave NdrYLF laser with a wavelength of 266 nm (hio = 4.66 eV), i.e. a photon energy between the GaN (3.5 eV) and AIN (6.2 eV) band gaps. The laser spot was about 1.5 am in diameter. The density of QDs in our samples is about lO" cm, so about 10 QDs was excited in the experiment. Polarization of radiation from the sample was rotated by a half-wave plate and was analyzed by Gian Thompson polarizer. The p-PL signal was detected by a liquid-nitrogen cooled UV-enhanced CCD camera. 

Let us consider first the case where the control photon is in the logical zero (H polarization state). The control photon will then travel undisturbed through the PBS, arriving in the spatial mode h. As required, the output photon is H polarized. In order for the scheme to work, a photon has to arrive also at the detector D3 in 63 given the input photon already in the mode b, this additional photon comes necessarily from the EPR pair, and is H polarized as it is transmitted by the PBS1. We know that the photons in a3 and 4 are correlated (2), so the photon in a is also in the horizontal polarization. Taking into account the — 45° rotation of the polarization on the paths 2, 4 operated by the half-wave plates, the input state in the PBS2 will then be state... 

Figure 3 The experimental setup. A type II Spontaneous parametric down-conversion is used both to produce the ancilla pair (in the spatial modes <23 and a4) and to produce the two input qubits (in the spatial modes ai and 0,2). In this case initial entanglement polarization is not desired, and it is destroyed by making the photons go through polarization filters which prepare the required input state. Half-wave plates have been placed in the photon paths in order to rotate the polarization compensators are able to nullify the birefringence effects of the non-linear crystal and of the polarizing beam splitters. Overlap of the wavepackets at the PBSs is assured through spatial and spectral filtering.

The 488.0 nm Coherent Radiation Model 520-B argon-ion laser of 300 mW power was focused on the center of the drop and the Raman light is detected perpendicular to both the laser beam and the sample tube. Qualitative polarization measurements were made by rotating the plane of polarization of the laser beam with a half-wave plate. In most of the spectra, it was not necessary to use a spike filter to attenuate the plasma lines. The spectra were recorded using a modified Cary 81 spectrophotometer employing a 9558A EMI photo-multiplier counting detection system. 

When the Voigt effect is utilized for the sample s magnetic pattern observation, the analyzer half-wave plate is set in order to convert elliptical polarization into either linear polarization or new elliptical polarization, with the smaller eccentricity depending on the sign of rotation in the incident ellipse [28]. The polarization transformation courses differ in terms of the images of differently magnetized domains (Figure 7.5). 

As the design of optical communication systems becomes more and more complex, an optical circulator with many input and output ports has become highly desirable. However, the port numbers for presently most commercial optical circulators are limited. In 2004, based on holographic spatial- and polarization-modules (HSPMs), two kinds design of holographic-type multi-port optical circulator were also proposed [Chen et al., 2004 Chen et al., 2004]. The HSPM is consisted of two HSWPs, an half-wave plate (H), and a Faraday rotator (FR). The merits of these designs include polarization-independence, compactness, high isolation, low polarization mode dispersion, and easy fabrication. Furthermore, the number of port can be scaled up easily. 

As shown in figure 8, the spatial- and polarization- module (SPM) is composed of two spatial walk-off polarizers (SWPs), a 45° Faraday rotator (FR), and a 45° half wave-plate (H). For easy understanding, an orthogonal x-y-z coordinate is introduced, symbol 0 represent an unpolarized light, and symbols and represent ft-polarized (y-polarized) and v-polarized (x-polarized) lights, respectively. 

A half-wave plate rotates the incident plane of polarization through an angle 20, where 6 is the angle of the polarized direction of the incident light beam relative to the direction of the optic axis (at the... 

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