The birefringent halfwave plate (HWP) polarization modulator, while new to the CMB field, has been used for decades at shorter wavelengths. The basic idea is simple; a polarized plane wave passing through a HWP will have its polarization orientation rotated by ∆ψ = 2θ, where θ is the angle between the incident polarization and one of the optical crystal axes. Rotating a HWP in front of a linear...

Optical Doppler shift demonstration experiments are not a simple task since the light source cannot usually be moved in a sufficiently smooth and uniform manner to keep the level of noise well below of that of the signal. For that reason most demonstration experiments are usually performed with sound or with microwaves. Previous works have been reported using a moving mirror in order to produce...

The Cornell Electron Storage ring facility CESR operates with 2 GeV multi-bunch electron and positron beams in a single beam-pipe. Electrostatic separators are used to separate the two counter-rotating beams at the parasitic crossings. When the beam energy was lowered from 5 GeV in 2003, the strength of the beam-beam interaction became a more important factor in beam-current limitations, result...

In this paper we consider the problem of optimal control of the model for a rotating body beam with a quadric cost function. We prove that there exists at least one optimal control and give necessary conditions for the control. Furthermore, we consider the problem of obstacle and prove the existence of optimal obstacle.

In this article we analyze the admissibility and the exact observability of a body-beam system when the output is taken in a point of attachment from the beam to the body. The single output case chosen here is the practical measurement of the strength, its velocity or its moment. We prove the exact observability for the moment and the admissibility for the other cases. These results are obtaine...

The resolution, bandwidth, and duty cycle of a laser beam scanner make it useful as an image recorder. Laser image recorders can have either a flatfield or a cylindrical recording surface, the flatfield being preferable in applications where dimensional stability is extremely important . A problem with flat field recording systems is the difficulty in obtaining a constant scan rate. This diffic...

We describe the experimental realization of a dynamical optical trap for atoms: the Rotating Off-resonant Dipole Optical (RODiO) Trap. A blue detuned circularly scanned laser beam creates a time averaged ;;box" for the atoms. We characterized this novel confinement technique by varying the trapping geometry and the laser beam parameters. Our observations agree well with a numerical model.

We demonstrated a pulse-to-pulse frequency-tunable LiNbO3 terahertz-wave parametric oscillator, pumped with a Q-switched Nd:YAG laser. Rapid tuning from 1 to 2 THz, with random frequency accessibility, was achieved by rotating the pump beam angle using an optical beam scanner and a telescope.

We have designed a toolbox that provides an environment for testing radiotherapy optimization techniques, objective functions, and constraints. A set of three-dimensional (3D) pencil beam dose distributions have been computed for a cylindrical phantom. The 6 MV pencil beams were computed using a superposition-based dose engine commissioned for an Elekta SL20 linear accelerator. Due to the cylin...

PURPOSE Intrafraction rotation of more than 45° and 25° has been observed for lung and prostate tumors, respectively. Such rotation is not routinely adapted to during current radiotherapy, which may compromise tumor dose coverage. The aim of the study was to investigate the geometric and dosimetric performance of an electromagnetically guided real-time dynamic multileaf collimator (DMLC) tracki...