Abstract: A method is provided for the determination a thickness error in a previously deposited layer using the reflection monitor signal of the currently-depositing layer. This thickness error is then used to compute corrections to the thickness of the currently-depositing layer and the next layer which corrects for the thickness error in the previous layer. The method is stable with respect to noise in the optical monitor signal. The technique is applicable for optical coating designs which are not necessarily quarter wave. The approach avoids the buildup of thickness errors from layer to layer and thus is applicable for very thick designs with many layers. Near the end of a currently depositing layer the monitor signal is used to fit the admittance of the base stack under the current layer. This establishes the parameters in an exact reflectance model used for the thickness monitoring of the current layer.

Abstract: This invention describes a means to monitor the deposition of a rugate filter such that the deposited filter will have the specified bandwidth, angular shift properties, and the correct wavelength of the reflectance peak.

Abstract: An optical interconnect that uses silver, gold, copper or other materials whose refractive index n is less than unity as the transmitting media has been conceived. This optical interconnect will transfer information over short distances faster than electrical conduction and faster than free-space optical transmission. The transfer speed is many times the free-space speed of light.

Abstract: A method is provided for the determination a thickness error in a previously deposited layer using the reflection monitor signal of the currently-depositing layer. This thickness error is then used to compute corrections to the thickness of the currently-depositing layer and the next layer which corrects for the thickness error in the previous layer. The method is stable with respect to noise in the optical monitor signal. The technique is applicable for optical coating designs which are not necessarily quarter wave. The approach avoids the buildup of thickness errors from layer to layer and thus is applicable for very thick designs with many layers. Near the end of a currently depositing layer the monitor signal is used to fit the admittance of the base stack under the current layer. This establishes the parameters in an exact reflectance model used for the rate or thickness monitoring of the current layer.

Abstract: An optical interference coating that transmits light in a narrow angular band has been achieved. This filter works in filtering light from different angles of arrival when it is operated in a tilted configuration to the incoming signal. Two such tilted filters whose normal vectors are rotated about an optical axis by 90 degrees enable light from all polarizations and from all angles of arrival to be effectively filtered by angle.

Abstract: An optical filter and a method for its design are provided that will transmit visible light and quickly cutoff to low transmission or high optical density in the near infrared wavelength region. This high optical density is achieved by either reflection or absorption of the incident light. Certain specified spectral wavelengths may be selected for absorption or reflection. These properties are achieved through the use of absorbing layers along with dielectric layers in the multilayer coating.

Abstract: A method is provided for the reduction of image noise due to multiple reflections from lens surfaces which incorporates weak absorption into the antireflection coatings of the lens surfaces. Even though weak absorption in the coatings may slightly decrease the transmittance, these special coatings with tailored absorption will increase image contrast and signal to noise ratios. Such coatings may also be designed to reduce image noise from surface scattering as from dust or scratches on the front surface of a lens.

Abstract: A method is provided for the determination of the time to terminate the deposition of an optical thin film using an exact model for the reflectance. This model is used to fit the reflectance measurements to determine the deposition rate, from which the time to deposit the entire layer is determined, as well as finding the admittance of the base stack at the beginning of the current layer. The layer deposition is terminated at the calculated time resulting in precise thickness control. This ability to fit the base admittance enables the determination of the reflection model parameters for each layer being deposited so that the accuracy of each layer is independent of previously deposited layers. This means that there is no build up of errors from layer to layer as the deposition progresses, enabling the deposition of coating designs with higher precision, including non periodic and non quarter wave designs.

Abstract: This invention describes a means to monitor the deposition of a rugate filter such that the deposited filter will have the specified bandwidth, angular shift properties, and the correct wavelength of the reflectance peak.

Abstract: A tunable Fabry-Perot filter that is less sensitive to angle of incidence is formed by replacing the cavity (air gap) with a partitioned cavity that has an effective refractive index greater than one. The partitioned cavity includes a pair of partitioned cavity dielectric layers formed on the reflectors on either side of the variable air gap. Each of the dielectric layers has an optical thickness that is less than one fourth the shortest wavelength in the tuning range of the filter. The resulting three-layer partitioned cavity has an effective optical thickness substantially equal to an integral multiple (m) of one half the transmitted wavelength within the tuning range of the filter.

Abstract: A complementary comb filter pair, and method for making same, are described, wherein each comb filter element of the complementary pair can be fabricated during the same deposition run. The complementary comb filter is masked so as to retard the thin film growth of the coating, for example, a dielectric material, so as to produce a desired wavelength transmission profile.

Abstract: A complementary comb filter pair, and method for making same, are described, wherein each comb filter element of the complementary pair can be fabricated during the same deposition run. The complementary comb filter is masked so as to retard the thin film growth of the coating, for example, a dielectric material, so as to produce a desired wavelength transmission profile.

Abstract: An apparatus and method for coupling an array of light beams extending predominantly in one direction into an output port. The light beams are rearranged into a desired shape which extends more equally along two directions than does incident array of light beams. The operation of the rearranging is wavelength insensitive. The rearranged light beams are focused onto the output port. For output ports having a small interface, the focal length of a lens focusing the rearranged light beams to the output port should be as short as possible.

Abstract: A polarizing beamsplitter includes an optical medium and a rugate filter embedded therein. The rugate filter has an average refractive index which varies with position on the rugate plane in the non-thickness direction, where the averaging is across the rugate film in the thickness direction. The variation in the rugate's average index compensates for variations in incident angle across a cone of a divergent light beam. In one embodiment, the period of the rugate is substantially constant across its surface. Most preferably, the amplitude of the rugate index variation has an apodizing amplitude envelope superimposed thereon to aid in coupling the rugate to a surrounding optical medium.

Abstract: A polarizing beamsplitter includes a gradient index film, such as a rugate filter, embedded in an optical medium. The rugate filter is comprises a thin film having a sinusoidal variation in refractive index through its thickness. The embedding medium may include a pair of prisms with the rugate filter between joining faces of the prisms. The rugate filter is embedded so that an incident beam in the embedding medium forms an angle with respect to a normal from the plane of the rugate filter. Embedded at a non-orthogonal angle, the rugate filter is highly transmissive for both the p- and s-polarized broadband components of the incident beam. The beamsplitter is highly reflective, however, at an s-polarization narrow wavelength reflection band determined by the refractive index variations of the rugate filter. Polarizing beamsplitters may be fabricated with multiple reflection bands, including reflection bands in spectral regions other than the visible spectrum.

Abstract: An automotive rear view mirror system comprises passive optical elements (which may include lenses, but must include one or an odd number of mirrors) configured to provide a wide field of view with a negative optical element having a small width dimension mounted externally and close to the body of the vehicle. In a basic embodiment, a small negative optical element, such as a convex mirror, is mounted outside the vehicle, and a larger positive optical element, such as a convex lens, is placed inside the vehicle. The optical elements are positioned to be substantially confocal, with the distance between them equal to the difference in their focal lengths, so as to cancel the curvature of field generated by the external element. The internal element magnifies the image to a size comparable to that obtained with a standard external flat mirror.

Abstract: A method is provided for monitoring and controlling the deposition of multiple layer thin films using a broadband spectral monitor and a generalized model of the film. A design specification, including the number of layers and the material, refractive index, and thickness of each layer, is provided for the desired thin film. A target optical thickness is computed for the end point of each layer using correction factors based on the generalized model, preferably a single layer model, of the multilayer thin film. A monitor chip, such as a silicon substrate, is used for monitoring the multiple layers of film deposition. During deposition of the film, a broadband spectral monitor (BBSM) comprising a source of broadband light is directed onto the monitoring chip. Light reflected by the monitoring chip is received by a photosensor that provides a broadband reflectance spectrum to a computer.

Abstract: A multiple pass band, thin film optical filter includes a first single pass band filter having a first pass band at a first wavelength, with a first quarterwave stack of thin film layers alternating between layers of a first dielectric material having a first refractive index and layers of a second dielectric material having a second refractive index, the optical thickness of each layer in the first stack being substantially one fourth of the first wavelength. A first half wave layer is interposed within the first stack and has an optical thickness which is an integral multiple of one half of the first wavelength, such that the reflectivities of the portions of the first stack on either side of the first half wave layer are substantially identical.

Abstract: A gradient index codeposition process involving refractive index clipping is used to fabricate rugate filters having multiple reflectance bands. During the codeposition process, whenever the superimposed sine wave profiles extend beyond either the upper or lower refractive index limits of the optical materials involved, the index is held at its bound (i.e., clipped). A rugate filter having a multiplicity of stop bands can be fabricated using a rather limited range of refractive index excursions during the codeposition process. Loss of optical density from index clipping can be corrected by a compensating increase in filter thickness.

Abstract: A binary optic lens is designed to achieve a predetermined effect on light propagating through the lens by specifying an initial lens design with a plurality of discontinuous subaperture regions, assigning each subaperture region a relative phase difference of 0 or .pi., and calculating the net intensity of light propagating through the lens by coherently summing the wave amplitudes for all of the subaperture regions at a given point in the image plane of the lens. The assigned phase difference for one of the subaperture regions is then changed and the intensity is recalculated by coherently summing the wave amplitudes for all of the subaperture regions at the given point. If the intensity increases over the previously calculated intensity, the changed phase difference is assigned to the selected subaperture region. The steps of changing, recalculating, and assigning are repeated for all of the subaperture regions to make one complete pass through the lens.