A multilayer stack of alternating low index and high index of refraction low loss dielectric mirror layers are formed on top of a metallic mirror surface, the thicknesses of the mirror layers being chosen to satisfy the Bragg condition at a selected incident angle of polarized light. The dielectric layer adjacent the metallic reflective mirror substrate can have a thickness which produces circularly polarized light exiting the apparatus. An electro-optical layer of EO material can be substituted for the dielectric layer adjacent the metallic mirror and a controlled elliptically polarized output can be produced by altering the electric field applied across the EO layer. This device can be used as a very high power high speed EO modulator.
A method of widening the directional range of view of a mirror device without enlarging the surface area of the device by suitably combining a number of partially-reflecting surfaces includes provision to avoid discontinuities and overlaps in the field of view. It also makes it possible for the viewer to visually identify an image with the particular reflector that generates the image seen in the image field and hence relate it to a zone of the field of visibility wherein the object is located. A device incorporating the method can be useful as a side-view mirror of an automobile.
Through silicon optical modulators (TSOM) formed in a silicon integrated circuit comprise a grating array of MOSFET elements. The TSOM's provide optical phase shifts from different areas which contrast with one another coherently. Phase modulated optical beams reflected from the grating interfere with one another and allow the modulation to be easily detected off-chip. In one embodiment, a two dimensional array has a gate structure which is used to modulate a light beam by forming accumulation layers. In another embodiment, a one dimensional array is formed using parallel gate strips, where alternate gates are used as reference reflectors.
A polarizer/modulator assembly (10) including a polarizing unit (12) and a modulator unit (14) that are selectively and independently positionable within a resonator cavity of a solid state diode slab laser. The polarizing unit (12) includes a pair of polarizing elements (32, 34) positioned in a "V-shaped" configuration so that both elements (32, 34) are positioned at Brewster's angle with respect to the beam path to combine to polarize the light in the same direction. The combination of the polarizing elements (32, 34) eliminates beam deflection when the polarizer unit (12) is inserted into the beam path. The polarizing elements (32, 34) are mounted in a metal housing (30) that captures rejected light from the polarizing elements (32, 34). The housing (30) includes a cooling tube (52) to control temperature of the housing (30) during temperature build-up caused by the rejected light.
Through silicon optical modulators (TSOM) formed in a silicon integrated circuit comprise an array of MOSFET elements which cause optical phase shifts of reflected light to identify a state of a signal. A polarization of the reflected light is modified by the phase shift and transmits the signal. The polarization of reflected light can be controlled by the angle of the incident light, by polarizing optical slits fabricated in the modulator, or by using a polarized mirror. Either embodiment allows the polarized reflected light to be nulled out. As such, a polarization of the reflected light is altered when the signal is applied to the modulator. The altered polarization can then be detected.
The present invention is an anti-reflective transparent article which includes a transparent substrate. The article also includes a first coating of metal oxide applied over the substrate. The first coating of metal oxide has a reflective index of about 1.8 to about 2.6. The article further includes a second coating of a metal oxide applied over the first coating of metal oxide. The second coating has a refractive index of about 1.44 to about 1.6. The reflectivity of the article, when measured at an angle of at least 50 degrees from normal, is at least three percentage points less than the reflectivity of the uncoated substrate at the same angle.