Half-wave plate

Fig. n.1. Principles of fluorescence up-conversion. NLC nonlinear crystal DM dichroic mirror HW half-wave plate PM photomultiplier. 

Figure 11. Simplified efficient blue generation scheme. A single pass of pulsed infrared light through an extracavity lens and nonlinear crystal is all that is required. A half-wave plate (HWP) may also be included if necessary.

Each nonlinear crystal was assessed in an extracavity single-pass arrangement at room temperature (figure 11). A half-wave plate was required for certain nonlinear crystals to provide the correct linear polarization. The relative performance of the four nonlinear crystals is summarized below in sections 7.1 to 7.4. 

Figure 12. Laser configuration for SHG experiments, incorporating four single-narrow-stripe (SNS) red laser diodes and a prism (P) for wavelength tuning (DM dichroic mirror HWP half-wave plate PC polarization cube HR high reflector 1.5% output coupler).

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... 

Figure 5.5 Numerically simulated Stokes polarization vector components 5j (dashed Une), S2 (solid line), and (dotted line) using Eq. (5.17) versus propagation direction z. Frames (a) is for N = 3 half-wave plates, while frames (b) and (c) are for = 6 and = 10 half-wave plates in a row. In all cases, the total crystal length is L and the rotary power is n = nJL.

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°.

Two special retardation devices find wide application in the design of optical po-larimeters. These are the quarter-wave plate with 8 = jc/2 and the half wave plate with 8 = re. The utility of a quarter-wave plate can be demonstrated by observing its effect on... 

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.

Retardation plates are frequently used in polarimetry instruments. Quarter-wave and half wave plates are most often used and may be fabricated in either wavelength-dependent or achromatic forms. 

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). 

Achromatic half-wave plates can be easily made from the combination of two quarter-wave Fresnel rhombs shown in Figure 9.3b. This geometry has the nice feature of removing the translation of the light beam that is associated with a single rhomb. 

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 I. Diagram of experimental apparatus used to obtain IRS and RIKES spectra. The Q-switched ruby is frequency-doubled to pump the dye laser. RIKES and its variations require two polarizers, For IRS the analyzer can be removed and the quarter-wave plate removed or replaced by a half-wave plate.

Figure 1.9. The optical parametric amplifier (OPA). BS, beam splitter TFP, thin-film polarizer HWP, half-wave plate IMP, dichroic beam splitter or long wave pass filter F,...

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].

The measurements were carried out with various laser peak intensities, pulse durations and contrast ratios. We used a half-wave plate and two polarizers to change the laser energy. The original position of the grating, which gives a 30-fs pulse, was determined with high accuracy from ionization rates... 

Fig. 2. Schematic diagram of the laser system to be used for a measurement of the 2Si/2-2P3/2 transition frequency in Si13+. (A/2 half wave plate, A/4 quarter wave plate, PBS polarizing beamsplitter, VCO voltage-controlled oscillator, AOM acoustooptic modulator, EOM electro-optic modulator)...

The noncollinear pump-probe experiment is depicted schematically in Fig. 13. The linearly polarized (P3) pump pulse is focused (LI) into the sample producing induced transmission changes. The polarization of the probe beam is adjusted to 45° relative to the pump with a half-wave plate (A./2) and a Gian polarizer (PI). By the help of an analyzer (P2) simultaneous detection of the parallel ( ) and perpendicular ( L) components of the energy transmission T(v, to) of the probe through the sample is installed. For blocked excitation (chopper, Ch) the sample transmission... 

Figure 13 Schematic of the setup of the pump-probe experiment with polarization resolution for the probing of the induced change in sample transmission. X/2 half-wave plate P1-P3 polarizers L1-L4 lenses D1-D5 detectors Ch chopper VD optical delay line. The sample is permanently moved in a plane perpendicular to the beams in order to avoid accumulative thermal effects.

Figure 8 Schematic of the optical system used to perform the Raman FID and echo experiments. P = Polarizer (D)BS = (dichroic) beamsplitter MD = manual delay line SD = computer-scanned delay line CSA = charge sensitive amplifier CH = chopper PH = pinhole S = sample F = bandpass and neutral density filters PD = photodiode A/D = analog-to-digital converter PC = computer PMT = photomultiplier X/2 = half-wave plate. (From Ref. 6.)...

Figure 1 OHD-RIKES experimental setup. DX = Doubling crystal GLP = Gian laser polarizer GTP = Glan-Thompson polarizer HWP = half-wave plate PD = photodiode PDC = prism dispersion compensator QWP = quarter-wave plate SF = spatial filter. (From Ref. 34.)...

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... 

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