A retroreflective element, for example a retroreflector or a retroreflective film, includes a regular arrangement of multiple reflective triples, each having three side surfaces that form an angle between 88° and 92°, preferably between 89° 50′ and 90° 10′ relative to one another, and particularly preferably stand perpendicularly on one another. At least one selected triple in the arrangement has a security element having at least one diffractive structure on at least one first side surface. A modulation depth of the security element is selected in such a manner that the security element cannot be perceived when the retroreflective element is illuminated at an illumination angle <10°.

A retroreflective element, for example a retroreflector or a retroreflective film, includes a regular arrangement of multiple reflective triples, each having three side surfaces that form an angle between 88° and 92°, preferably between 89° 50′ and 90° 10′ relative to one another, and particularly preferably stand perpendicularly on one another. At least one selected triple in the arrangement has a security element having at least one diffractive structure on at least one first side surface. A modulation depth of the security element is selected in such a manner that the security element cannot be perceived when the retroreflective element is illuminated at an illumination angle <10°.

An electro-optic modulator comprising at least one nanodisordered potassium tantalate niobate crystal; first and second conductors operatively connected to the nanodisordered potassium tantalate niobate crystal adapted to be connected to a voltage source to modulate light passing there through; whereby light is modulated by passing through the nanodisordered potassium tantalate niobate crystal. A method for modulating light comprising providing at least one at least one nanodisordered potassium tantalate niobate crystal; providing first and second conductors operatively connected to the nanodisordered potassium tantalate niobate crystal adapted to be connected to a voltage source to modulate light passing there through; providing an interrogating light beam striking at least one nanodisordered potassium tantalate niobate crystal; modulating light passing through the nanodisordered potassium tantalate niobate crystal; and receiving a modulated light beam.

An electro-optic modulator comprising at least one nanodisordered potassium tantalate niobate crystal; first and second conductors operatively connected to the nanodisordered potassium tantalate niobate crystal adapted to be connected to a voltage source to modulate light passing there through; whereby light is modulated by passing through the nanodisordered potassium tantalate niobate crystal. A method for modulating light comprising providing at least one at least one nanodisordered potassium tantalate niobate crystal; providing first and second conductors operatively connected to the nanodisordered potassium tantalate niobate crystal adapted to be connected to a voltage source to modulate light passing there through; providing an interrogating light beam striking at least one nanodisordered potassium tantalate niobate crystal; modulating light passing through the nanodisordered potassium tantalate niobate crystal; and receiving a modulated light beam.

The invention relates to a multi-pass etalon-based optical filter in which input light once reflected from the etalon is returned back to the etalon for a second reflection to enhance etalon contrast. The external mirror may be tilted relative to the etalon so that two planes of incidence are orthogonal. The multi-pass etalon-based optical filter may be used to clean scattered light from an excitation wavelength in Raman and Brillouin spectroscopy.

A system for infrastructure system calibration includes a sensor configured to be mounted to an infrastructure component and configured to detect an object. A corner reflector has an optical pattern and is arranged within a field of view of the sensor. The corner reflector has three surfaces that meet at a point.

An improved retroreflector assembly is provided. The retroreflector assembly has a retroreflector comprising three plates having optically flat reflective surfaces disposed at right angles to each other, wherein the retroreflector has a clear aperture distance, and an axis aligned equidistantly from the three plates and extending from a vertex of the retroreflector, a housing for receipt therein of the retroreflector, at least one mounting element extending from the retroreflector, wherein the mounting element at least partially secures the retroreflector to the housing, and a vertical height smaller in distance than the clear aperture distance in a direction parallel to the axis of the retroreflector, and a method for mounting the same.

An improved retroreflector assembly is provided. The retroreflector assembly has a retroreflector comprising three plates having optically flat reflective surfaces disposed at right angles to each other, wherein the retroreflector has a clear aperture distance, and an axis aligned equidistantly from the three plates and extending from a vertex of the retroreflector, a housing for receipt therein of the retroreflector, at least one mounting element extending from the retroreflector, wherein the mounting element at least partially secures the retroreflector to the housing, and a vertical height smaller in distance than the clear aperture distance in a direction parallel to the axis of the retroreflector, and a method for mounting the same.

A system for the acquisition of an image of a lead aircraft by a follower aircraft flying behind the lead aircraft. Such acquisition is made difficult when the ambient brightness drops, and even impossible at night. The system allows such night acquisition and comprises at least one camera installed on or in the follower aircraft, a lighting device provided on the follower aircraft and oriented at least partially towards the lead aircraft and a retroreflective device of retroreflector type disposed on the lead aircraft. When lit, the retroreflective device allows the camera to acquire an image of the zones marked by the retroreflective device despite the reduced brightness.

A system for the acquisition of an image of a lead aircraft by a follower aircraft flying behind the lead aircraft. Such acquisition is made difficult when the ambient brightness drops, and even impossible at night. The system allows such night acquisition and comprises at least one camera installed on or in the follower aircraft, a lighting device provided on the follower aircraft and oriented at least partially towards the lead aircraft and a retroreflective device of retroreflector type disposed on the lead aircraft. When lit, the retroreflective device allows the camera to acquire an image of the zones marked by the retroreflective device despite the reduced brightness.