A freeform varifocal optical assembly includes at least three optical modules including a first plurality of optical elements including Pancharatnam-Berry phase (PBP) lenses, polarization sensitive hologram (PSH) lenses, metamaterials, or combinations thereof. The plurality of optical elements of each optical module include a property associated with a Zernike polynomial. Each of the first and the three optical modules are configurable between a plurality of optical powers. The freeform varifocal optical assembly is configurable to output a predetermined wavefront in response to an input wavefront.

A method of additive manufacture is disclosed. The method may include creating, by a 3D printer contained within an enclosure, a part having a weight greater than or equal to 2,000 kilograms. A gas management system may maintain gaseous oxygen within the enclosure atmospheric level. In some embodiments, a wheeled vehicle may transport the part from inside the enclosure, through an airlock, as the airlock operates to buffer between a gaseous environment within the enclosure and a gaseous environment outside the enclosure, and to a location exterior to both the enclosure and the airlock.

According to one embodiment, a polarization conversion element includes a first substrate including a first plane electrode and a first control electrode, a second substrate, and a liquid crystal layer. The first control electrode comprises a first strip electrode, a second strip electrode, a third strip electrode, and a first common electrode. The first strip electrode and the first common electrode are orthogonal to each other, respective extension directions of the first to third strip electrodes are different from each other, and an angle formed by the first strip electrode and the third strip electrode is greater than an angle formed by the first strip electrode and the second strip electrode.

An electroactive optical device that includes an optical substrate; a layer that includes an electroactive material capable of linearly polarizing electromagnetic radiation; at least two transparent electrodes, spaced one from the other, and each independently in contact with the layer containing the electroactive material; a source capable of applying an electric potential between the at least two electrodes; and a birefringent layer. Electromagnetic radiation transmitting through the device includes a first polarization state in the absence of an electrical potential between the at least two electrodes and the electromagnetic radiation transmitting through the device includes a second polarization state that is different from the first polarization state, in the presence of an electrical potential between the at least two electrodes. The electroactive optical device is operable to circularly polarize or elliptically polarize transmitted radiation.

A wearable display system includes an eyepiece stack having a world side and a user side opposite the world side. During use, a user positioned on the user side views displayed images delivered by the wearable display system via the eyepiece stack which augment the user's field of view of the user's environment. The system also includes an optical attenuator arranged on the world side of the of the eyepiece stack, the optical attenuator having a layer of a birefringent material having a plurality of domains each having a principal optic axis oriented in a corresponding direction different from the direction of other domains. Each domain of the optical attenuator reduces transmission of visible light incident on the optical attenuator for a corresponding different range of angles of incidence.

A method and an apparatus for collecting powder samples in real-time in powder bed fusion additive manufacturing may involves an ingester system for in-process collection and characterizations of powder samples. The collection may be performed periodically and uses the results of characterizations for adjustments in the powder bed fusion process. The ingester system of the present disclosure is capable of packaging powder samples collected in real-time into storage containers serving a multitude purposes of audit, process adjustments or actions.

According to an aspect of an embodiment, operations may include receiving a light wave and generating a pumping wave by performing polarization modulation on the light wave based on a bit stream. The pumping wave may include a first polarization component having a first polarization and a second polarization component having a second polarization and having a same wavelength as the first polarization component. The operations may also include emitting the pumping wave in an optical medium such that the pumping wave amplifies an optical signal propagating within the optical medium.

A switchable privacy display comprises a spatial light modulator with output polariser, a reflective polariser, a polar control liquid crystal retarder and an additional polariser. The electrodes of the polar control liquid crystal retarder are patterned with a mark. In wide angle and narrow angle operational modes, the electrodes of the liquid crystal retarder are driven such that the mark is not visible. In a mark display state, the electrodes are driven to provide visibility of the mark in reflected light to an off-axis observer.

Systems and methods for temporal amplitude modulation of an optical beam. An exemplary system may include a birefringent fiber positioned between two polarizers, or between a polarized input light source and an output polarizer. Light may enter the birefringent fiber as linearly polarized. Depending on birefringence and orientation of the birefringent fiber, the polarization state changes as the light propagates through the birefringent fiber. This changed polarization state then enters the output polarizer, for which transmission is a function of the polarization state and the relative orientation of the polarization axis. The polarization state emerging from the birefringent fiber may be changed by modulating the fiber birefringence, for example through application of an external stress. Net transmittance of the system may be varied according to a magnitude of an external force (e.g., pressure) to some or all of the birefringent fiber.

A reconfigurable polarization rotator is formed of an array of very small liquid crystal (LC) cells (e.g., cells of less than 10 μm in width, termed “microcells”), referred to hereinafter as “microcells”. Each LC microcell is addressable by a separate electrical voltage input that independently controls the polarization rotation performed by the associated LC microcell. By defining a set of adjacent microcells to be held at the same voltage level, that group may be used to form a polarization rotator window of a proper size for a first fiber array configuration. When a fiber array of a different configuration (say, an array with twice the pitch) is used, a different-sized group of adjacent LC microcells is held at a common voltage level so as to form a reconfigured “window” of a new dimension.