A method of dispersion compensation in an optical device is disclosed. The method may include identifying a first hologram grating vector of a grating medium of the optical device. The first hologram grating vector may correspond to a first wavelength of light. The method may include determining a probe hologram grating vector corresponding to a second wavelength of light different from the first wavelength of light. The method may also include determining a dispersion-compensated second hologram grating vector based at least in part on the probe hologram grating vector and the first hologram grating vector. A device for reflecting light is disclosed. The device may include a grating medium and a grating structure within the grating medium. The grating medium may include a dispersion compensated hologram.

A sight assembly for mounting to a weapon. A holographic optical element and a light source are in a fixed angular configuration with respect to one another, but may be adjusted either together or individually in a horizontal or vertical direction. The sight assembly may have a mirror or lens. An adjustment mechanism is provided where a shaft includes at least two portions wherein the two portions of the shaft of the screw have different pitch directions and/or pitch dimensions allowing for slight adjustment the assembly. The light source may be a vertical-cavity surface emitting laser (VCSEL). A temperature sensor may sense a temperature of the VCSEL. A current to the VCSEL may be adjusted based on a change in the temperature such that the output wavelength is approximately the same as a desired wavelength. The assembly may further allow for perceived image distance adjustment using parallax mismatch.

We describe a window assembly comprising: a window pane comprising a glass or plastic sheet; and a layer of holographic recording medium attached to said glass or plastic sheet; wherein said layer of holographic recording medium has recorded within the medium a volume hologram configured to direct light incident onto said glass or plastic sheet to propagate within a thickness of said glass or plastic sheet. In embodiments the volume hologram is fabricated by recording a transmission hologram and shrinking the recorded hologram to convert the transmission hologram to an edge-directing hologram configured to direct light in a direction to be totally internally reflected within the window pane, for example at greater than 40, 50, 60, 70, 75 or 80 to a normal to the surface of the hologram.

Systems and methods are provided herein. An exemplary system may include a laser source, the laser source having a laser center wavelength; at least one narrowband optical element receiving light emitted by the laser, the narrowband optical element having a filter center wavelength, the narrowband optical element being arranged such that the filter center wavelength is initially spectrally aligned with the laser center wavelength, the filter center wavelength changing in response to a temperature change such that the filter center wavelength is not substantially aligned with the laser center wavelength; and a passive adjustment mechanism coupled to the narrowband optical element, the passive adjustment mechanism including an actuator, the actuator moving in response to the temperature change, the actuator motion rotating the narrowband optical element, the rotation compensating for the temperature change such that the filter center wavelength and laser center wavelength remain spectrally aligned.

Systems and methods are provided herein. An exemplary system may include a laser source, the laser source having a laser center wavelength; at least one narrowband optical element receiving light emitted by the laser, the narrowband optical element having a filter center wavelength, the narrowband optical element being arranged such that the filter center wavelength is initially spectrally aligned with the laser center wavelength, the filter center wavelength changing in response to a temperature change such that the filter center wavelength is not substantially aligned with the laser center wavelength; and a passive adjustment mechanism coupled to the narrowband optical element, the passive adjustment mechanism including an actuator, the actuator moving in response to the temperature change, the actuator motion rotating the narrowband optical element, the rotation compensating for the temperature change such that the filter center wavelength and laser center wavelength remain spectrally aligned.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, an optical device includes: a first optically diffractive component including a first diffractive structure configured to diffract a first color of light having a first incident angle at a first diffracted angle, a second optically diffractive component including a second diffractive structure configured to diffract a second color of light having a second incident angle at a second diffracted angle, a first reflective layer configured to totally reflect the first color of light having the first incident angle and transmit the second color of light, and a second reflective layer configured to totally reflect the second color of light having the second incident angle. The first reflective layer is between the first and second diffractive structures, and the second diffractive structure is between the first and second reflective layers.