Systems and methods for preventing high-radiant-flux light, such as laser light or a nuclear flash, from causing harm to imaging devices, such as a camera or telescope. In response to detection of high-radiant-flux light, the proposed systems have the feature in common that a shutter is closed sufficiently fast that light from the source will be blocked from reaching the image sensor of the imaging device. Some of the proposed systems include a folded optical path to increase the allowable reaction time to close the shutter.

Provided are a reflective metasurface primary mirror and secondary mirror, and a telescope system. The reflective metasurface primary mirror includes a transparent substrate and a primary mirror metasurface functional unit pattern disposed on the transparent substrate. The primary mirror metasurface functional unit pattern includes an anisotropic primary mirror subwavelength structure disposed in a set annular region, and a phase introduced by the primary mirror subwavelength structure satisfies a primary mirror phase distribution. The set annular region encircles a light-transmissive hole, and light reflected by the reflective metasurface secondary mirror is focused through the light-transmissive hole.

Provided are a reflective metasurface primary mirror and secondary mirror, and a telescope system. The reflective metasurface primary mirror includes a transparent substrate and a primary mirror metasurface functional unit pattern disposed on the transparent substrate. The primary mirror metasurface functional unit pattern includes an anisotropic primary mirror subwavelength structure disposed in a set annular region, and a phase introduced by the primary mirror subwavelength structure satisfies a primary mirror phase distribution. The set annular region encircles a light-transmissive hole, and light reflected by the reflective metasurface secondary mirror is focused through the light-transmissive hole.

A diopter adjustment mechanism comprises a scope tube with a first female thread and a second female thread. The first female thread has a first pitch and is disposed on the scope tube forming a spiral thread and lands between the spiral threads. The second female thread has a second pitch and is disposed on the lands of the first female thread. A jam nut has a male thread corresponding to and engaging the second female thread. The pitch of the first female thread is greater than the pitch of the second female thread.

A diopter adjustment mechanism comprises a scope tube with a first female thread and a second female thread. The first female thread has a first pitch and is disposed on the scope tube forming a spiral thread and lands between the spiral threads. The second female thread has a second pitch and is disposed on the lands of the first female thread. A jam nut has a male thread corresponding to and engaging the second female thread. The pitch of the first female thread is greater than the pitch of the second female thread.

A manufacturing method creates a type of telescope which is athermal, lightweight, optical quality for visible and IR applications. The method includes: a) optical mirrors being made by immersing a master, that is an optical component with a curvature opposite to the mirror required into an electrolytic bath where the applied current transfers metal ions and deposit them on the master, the cathode, as a layer, b) the layer being bonded by an adhesive, solder or any other attachment process to a mechanical reinforcing structure, c) after the hardening of the bond or glue, the thin layer being finally released from the master and having maintained the optical quality of the master.

The master or mandrel can be cleaned and reused for repeating this method and manufacturing large series of telescopes.

An optical assembly including a plurality of metamirrors, where each metamirror includes a substrate, a reflective layer formed to the substrate, an array of optical metaelements extending from the reflective layer and an array of micro-actuators coupled to the substrate opposite to the reflective layer. The combination of the micro-actuators are controlled to control the orientation and bending of the metamirrors to set how the metaelements focus a light beam that is reflected off of the reflective layers.

An optical assembly including a plurality of metamirrors, where each metamirror includes a substrate, a reflective layer formed to the substrate, an array of optical metaelements extending from the reflective layer and an array of micro-actuators coupled to the substrate opposite to the reflective layer. The combination of the micro-actuators are controlled to control the orientation and bending of the metamirrors to set how the metaelements focus a light beam that is reflected off of the reflective layers.

Provided is an optical system having a configuration capable of attaining a large light-gathering power while producing a maximum light-gathering power easily and inexpensively with a minimum material. An offset optical system according to the present invention comprises: a primary mirror composed of at least part of one of two optical element halves obtained by dividing an optical element having a concave shape curved only in one direction, in an intermediate position of a length along a curvature thereof, wherein the optical element is configured to reflect and focus light from an object, into a linear focus; a sub-mirror disposed between the primary mirror and the linear focus and configured to transmit or reflect light reflected by the primary mirror, thereby focusing the light into a point focus; wherein, when: a direction tangent to the curvature in the intermediate position of the optical element is defined as an x-axis; a direction which is perpendicular to the x-axis and in which the object is located is defined as a y-axis; and a direction orthogonal to the x-axis and the y-axis is defined as a z-axis, the sub-mirror is offset parallel to the x-axis by a given distance toward an edge of the primary mirror located distal to the y-axis.

Provided is an optical system having a configuration capable of attaining a large light-gathering power while producing a maximum light-gathering power easily and inexpensively with a minimum material. An offset optical system according to the present invention comprises: a primary mirror composed of at least part of one of two optical element halves obtained by dividing an optical element having a concave shape curved only in one direction, in an intermediate position of a length along a curvature thereof, wherein the optical element is configured to reflect and focus light from an object, into a linear focus; a sub-mirror disposed between the primary mirror and the linear focus and configured to transmit or reflect light reflected by the primary mirror, thereby focusing the light into a point focus; wherein, when: a direction tangent to the curvature in the intermediate position of the optical element is defined as an x-axis; a direction which is perpendicular to the x-axis and in which the object is located is defined as a y-axis; and a direction orthogonal to the x-axis and the y-axis is defined as a z-axis, the sub-mirror is offset parallel to the x-axis by a given distance toward an edge of the primary mirror located distal to the y-axis.