50,318 research outputs found
Low loss dichroic plate
A low loss dichroic plate is disclosed for passing radiation within a particular frequency band and reflecting radiation outside of that frequency band. The dichroic plate is comprised of a configuration of dipole elements defined by slots formed in a conductive plate. The slots are dimensioned so as to pass radiation of a selected frequency and are shaped so as to minimize the relationship between that frequency and the tilt angle of the plate relative to the direction of radiation. The slots are arranged so as to minimize signal power loss due to cross polarization effects
Polarimeter for transient measurement Patent
Automatic polarimeter capable of measuring transient birefringence changes in electro-optic material
Magneto-optic detection system with noise cancellation
In a magneto-optic readout system, a polarized beam of light from a laser is subjected to the magneto-optical effect of a magnetic record medium, and then passed through an analyzer which resolves the beam into two orthogonal vector components so oriented that the two components are of equal amplitude when the angle of rotation due to the magneto-optic effect is zero. Separate photodetectors produce two output signals which are proportional to the amplitudes of the vector components. The two output signals are combined in a differential amplifier through separate logarithmic transfer circuits to produce an output signal proportional to the ratio of the two original detector signals
Performance of Polarization-based Stereoscopy Screens
The screen is a key part of stereoscopic display systems using polarization
to separate the different channels for each eye. The system crosstalk,
characterizing the imperfection of the screen in terms of preserving the
polarization of the incoming signal, and the scattering rate, characterizing
the ability of the screen to deliver the incoming light to the viewers,
determine the image quality of the system. Both values will depend on the
viewing angle. In this work we measure the performance of three silver screens
and three rear-projection screens. Additionally, we measure the surface texture
of the screens using white-light interferometry. While part of our optical
results can be explained by the surface roughness, more work is needed to
understand the optical properties of the screens from a microscopic model.Comment: almost identical to journal version, but better image qualit
Anisotropy of Magnetoresistance Hysteresis around the Quantum Hall State in Tilted Magnetic Field
We present an anisotropy of the hysteretic transport around the spin
transition point at Landau level filling factor in tilted magnetic
field. When the direction of the in-plane component of the magnetic field
is normal to the probe current , a strong hysteretic
transport due to the current-induced nuclear spin polarization occurs. When
is parallel to , on the other hand, the hysteresis almost
disappears. We also demonstrate that the nuclear spin-lattice relaxation rate
at the transition point increases with decreasing angle between
the directions of and . These results suggest that the
morphology of electron spin domains around is affected by the
current direction.Comment: 4 pages, 4 figure
Information-Control Software for Handling Serial Devices in an EPICS Environment
Each accelerator control system has a variety of measurement devices. One of
the most common types of instrument interfaces used for their control is a
serial (RS-232) bus. It is inexpensive and adequate for relatively simple
measurement and control devices such as switchers, amplifiers, voltmeters, and
steppermotors. Since the RS-232 specification is very broad and does not
require uniformity above the basic communication protocol level, one of the
major problems associated with the use of RS-232 is that the command protocol
for each device is unique. This makes it difficult to design generic drivers
for RS-232 and also hampers efforts to design generic troubleshooting methods.
This paper presents software developed independently at three other labs and
integrated into a single system at Jefferson Lab to handle serial devices in a
generic manner. The software is based on the EPICS toolkit and uses a 3-tier
architecture including a common serial driver at the bottom, a top-level
protocol to specify individual device commands in a generic manner, and a
mid-level of software to "glue" the two together.Comment: 3 pages, paper presented at Conference ICALEPCS-2001, San Jose, CA,
November, 200
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