Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for correcting finite floating-point numerical simulation and optimization. Defining a loss function within a simulation space composed of a plurality of voxels each having an initial degree of freedom, the simulation space encompassing one or more interfaces of the component; defining an initial structure for the one or more interfaces in the simulation space; calculating, using a computer system with a finite floating-point precision, values for an electromagnetic field at each voxel using a finite-difference time domain solver to solve Maxwell's equations; and determining, for each voxel, whether to increase a respective numerical precision of respective values representing behavior of the electromagnetic field at the voxel above a threshold precision by the computer system and, in response, assigning one or more additional degrees of freedom to the voxel.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for designing a multimodal photonic component. In one aspect, a method includes defining a loss function within a simulation space including multiple voxels and encompassing features of the multimodal photonic component. The loss function corresponds to a target output mode profile for an input mode profile, where the target output mode profile includes a relationship between a set of operating conditions and one or more supported modes of the multimodal photonic component at a particular operative wavelength. The initial structure is defined for one or more features, where at least some of the voxels corresponding to features have a dimension smaller than a smallest operative wavelength of the multimodal photonic component, and values for structural parameters for the features are determined so that a loss according to the loss function is within a threshold loss.

Abstract: A computer-implemented method for designing a dispersive optical component includes: (i) defining a loss function within a simulation space composed of multiple voxels, the simulation space encompassing optical interfaces of the component, the loss function corresponding to a target dispersion profile for the component including a relationship between a scattering angle and a wavelength of an incident electromagnetic field for different operative wavelengths; (ii) defining an initial structure for the optical interfaces, at least some of the voxels corresponding to each optical interface having a dimension smaller than a smallest operative wavelength of the component; and (iii) determining, using a computer system, a structure for each optical interface using a finite-difference time domain solver to solve Maxwell's equations so that a loss determined according to the loss function is above a specified threshold.

Abstract: Methods for designing a mode-selective optical device including one or more optical interfaces defining an optical cavity include: defining a loss function within a simulation space encompassing the optical device, the loss function corresponding to an electromagnetic field having an operative wavelength within the optical device resulting from an interaction between an input electromagnetic field at the operative wavelength and the one or more optical interfaces of the optical device; defining an initial structure for each of the one or more optical interfaces, each initial structure being defined using a plurality of voxels; determining values for at least one structural parameter and/or at least one functional parameter of the one or more optical interfaces by solving Maxwell's equations; and defining a final structure of the one or more optical interfaces based on the values for the one or more structural and/or functional parameters.

Abstract: Systems and methods for designing a hybrid neural network comprising at least one physical neural network component and at least one digital neural network component. A loss function is defined within a design space composed of a plurality of voxels, the design space encompassing one or more physical structures of the at least one physical neural network component and one or more architectural features of the digital neural network. Values are determined for at least one functional parameter for the one or more physical structures, and the at least one architectural parameter for the one or more architectural features, using a domain solver to solve Maxwell's equations so that a loss determined according to the loss function is within a threshold loss. Final structures are defined for the at least one physical neural network component and the digital neural network component based on the values.

Abstract: A method that includes: providing a substrate including a layer of a crystalline material having a first surface; and exposing the first surface to an environment under conditions sufficient to cause epitaxial growth of a layer of a deposition material on the first surface, wherein exposing the first surface to the environment includes illuminating the substrate with light at a first wavelength while causing the epitaxial growth of the layer of the deposition material. The first surface includes one or more discrete growth sites at which an epitaxial growth rate of the quantum confined nanostructure material is larger than areas of the first surface away from the growth sites by an amount sufficient so that the deposition material forms a quantum confined nanostructure at each of the one or more discrete growth sites.

Abstract: An example method may include receiving, from a client computing device, an indication of a target drop-off spot for an object within a first virtual model of a first region of a delivery destination. A second virtual model of a second region of the delivery destination may be determined based on sensor data received from one or more sensors on a delivery vehicle. A mapping may be determined between physical features represented in the first virtual model and physical features represented in the second virtual model to determine an overlapping region between the first and second virtual models. A position of the target drop-off spot within the second virtual model may be determined based on the overlapping region. Based on the position of the target drop-off spot within the second virtual model, the delivery vehicle may be navigated to the target drop-off spot to drop off the object.

Abstract: The subject matter of this specification generally relates to modular vehicles including separable pod and base units. In some implementations, a computing system installed in a vehicle base identifies a vehicle pod that is detachably connected to a chassis on the vehicle base. In response to identifying that the vehicle pod is detachably connected to the chassis on the vehicle base, a communications link can be established between the computing system installed in the vehicle base and a computing system installed in the vehicle pod. Based on information obtained through the communications link, the computing system installed in the vehicle base can determine a particular configuration of the vehicle pod that is detachably connected to the chassis. The computing system can then verify that the vehicle base can safely transport the vehicle pod while the vehicle pod is detachably connected.

Abstract: A computer-implemented method for designing an image processing device includes defining a loss function within a simulation space composed of a plurality of voxels; defining an initial structure for one or more physical features of a metasurface and one or more architectural features of a neural network in the simulation space; determining, using a computer system, values for at least one structural parameter, and/or at least one functional parameter for the one or more physical features and at least one architectural parameter for the one or more architectural features, using a numerical solver to solve Maxwell's equations so that a loss determined according to the loss function is within a threshold loss; defining a final structure of the metasurface based on the values for the one or more structural parameters; and defining a final structure of the neural network based on the values for the at least one architectural parameter.

Abstract: A computing system may obtain, for each vehicle of a plurality of vehicles located within a location area, navigation data that indicates a travel route for the vehicle. Based on the navigation data for the plurality of vehicles, the computing system determines a subset of the plurality of vehicles that are within a threshold distance of each other and have respective travel routes that at least partially overlap. The computing system selects, based on a set of selection parameters, two or more vehicles among the subset of vehicles to form a platoon of vehicles that travel in a coordinated arrangement in proximity to each other during at least a portion of the respective travel routes of the selected vehicles. The computing system can direct the selected vehicles to form the platoon of vehicles.

Abstract: A method that includes: providing a substrate including a layer of a crystalline material having a first surface; and exposing the first surface to an environment under conditions sufficient to cause epitaxial growth of a layer of a deposition material on the first surface, wherein exposing the first surface to the environment includes illuminating the substrate with light at a first wavelength while causing the epitaxial growth of the layer of the deposition material. The first surface includes one or more discrete growth sites at which an epitaxial growth rate of the quantum confined nanostructure material is larger than areas of the first surface away from the growth sites by an amount sufficient so that the deposition material forms a quantum confined nanostructure at each of the one or more discrete growth sites.

Abstract: An example method may include receiving, from a client computing device, an indication of a target drop-off spot for an object within a first virtual model of a first region of a delivery destination. A second virtual model of a second region of the delivery destination may be determined based on sensor data received from one or more sensors on a delivery vehicle. A mapping may be determined between physical features represented in the first virtual model and physical features represented in the second virtual model to determine an overlapping region between the first and second virtual models. A position of the target drop-off spot within the second virtual model may be determined based on the overlapping region. Based on the position of the target drop-off spot within the second virtual model, the delivery vehicle may be navigated to the target drop-off spot to drop off the object.

Abstract: Methods for designing a mode-selective optical device including one or more optical interfaces defining an optical cavity include: defining a loss function within a simulation space encompassing the optical device, the loss function corresponding to an electromagnetic field having an operative wavelength within the optical device resulting from an interaction between an input electromagnetic field at the operative wavelength and the one or more optical interfaces of the optical device; defining an initial structure for each of the one or more optical interfaces, each initial structure being defined using a plurality of voxels; determining values for at least one structural parameter and/or at least one functional parameter of the one or more optical interfaces by solving Maxwell's equations; and defining a final structure of the one or more optical interfaces based on the values for the one or more structural and/or functional parameters.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for tuning photonic device performance. In one aspect, a method includes receiving an initial photonic device configuration including multiple coupling structures and multiple photonic components. A first amount of light coupling between a first photonic component and a second photonic component of the multiple photonic components is received, which depends upon a subset of the coupling structures that are located between the first photonic component and the second photonic component. One or more coupling structures of the subset of coupling structures located between the first photonic component and the second photonic component are determined to be removed to cause the light coupling between the first photonic component and the second photonic component to change from the first amount of coupling to a target amount of coupling.

Abstract: Methods for designing a mode-selective optical device including one or more optical interfaces defining an optical cavity include: defining a loss function within a simulation space encompassing the optical device, the loss function corresponding to an electromagnetic field having an operative wavelength within the optical device resulting from an interaction between an input electromagnetic field at the operative wavelength and the one or more optical interfaces of the optical device; defining an initial structure for each of the one or more optical interfaces, each initial structure being defined using a plurality of voxels; determining values for at least one structural parameter and/or at least one functional parameter of the one or more optical interfaces by solving Maxwell's equations; and defining a final structure of the one or more optical interfaces based on the values for the one or more structural and/or functional parameters.

Abstract: A computing system may obtain, for each vehicle of a plurality of vehicles located within a location area, navigation data that indicates a travel route for the vehicle. Based on the navigation data for the plurality of vehicles, the computing system determines a subset of the plurality of vehicles that are within a threshold distance of each other and have respective travel routes that at least partially overlap. The computing system selects, based on a set of selection parameters, two or more vehicles among the subset of vehicles to form a platoon of vehicles that travel in a coordinated arrangement in proximity to each other during at least a portion of the respective travel routes of the selected vehicles. The computing system can direct the selected vehicles to form the platoon of vehicles.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for changing a distributed mode loudspeaker's fundamental frequency. One of the systems may include a light emitting diode display that includes an array of pixels, each pixel including, for each color of multiple colors, a directional light emitter and a wide-angle light emitter, a first combination of all the directional light emitters configured to generate a first display image viewable within a first viewing angle, and a second combination of all the wide-angle light emitters configured to generate a second display image concurrently with the generation of the first display image that is viewable within a second viewing angle. The first display image is a different image than the second display image and the first viewing angle is a narrower viewing angle than, and included within, the second viewing angle.

Abstract: An optical device that includes: a base layer; a first region supported by the base layer, the first region including a first plurality of quantum-confined nanostructures and having a first density of quantum-confined nanostructures; a second region supported by the base layer, the first and second regions being non-overlapping regions, the second region having a second density of quantum-confined nanostructures lower than the first density; and an optical confinement structure supported by the base layer and configured to guide at least one transverse optical mode between a first end and a second end of the optical confinement structure. The first region substantially overlaps with the at least one transverse optical mode, and the first density varies across a cross-section of the optical device.

Abstract: Techniques of providing illumination to a head-mounted display (HMD) involve providing off-board illumination apart from the HMD. An off-board illumination unit delivers the illumination to the HMD via optical fibers. The optical fibers are lightweight and do not restrict motion of a user. Because the power source is less restricted, the off-board illumination unit provides flexibility in the hardware used to generate the illumination. For example, the illumination unit may use red, green, and blue narrow-band diode lasers. Further, by controlling modes in the fiber and providing additional light-guiding hardware, the angles at which light strikes LCD pixels may be largely restricted to certain specified angles. Restricted angles of incidence enable the use of fast-switching liquid crystals without degrading the image quality. Such a restriction allows for high-resolution imaging using rapid switching of the liquid crystal which enables very low latencies.

Abstract: A system and a method for determining local electric field strengths, the system including: a light source module configured to emit light; a plurality of electric field sensors, each sensor including a light input portion and a light output portion, each sensor including an electro-optic material arranged in a path of at least some of the received light, an optical property of the electro-optic material being variable depending on a local electric field strength at the sensor, and the electro-optic material being arranged in the sensor such that a property of the output light varies depending on the local electric field strength; a light detection module arranged to receive the output light from the sensors; and a processing module in communication with the light detection module, the processing module being programmed to determine a corresponding value for the electric field strength local to each of the sensors.