An off-axis three-mirror optical system with freeform surfaces comprised an aperture, a primary mirror, a secondary mirror, a tertiary mirror, and a detector. The aperture is located on an incident light path. The primary mirror is located on an aperture side. The secondary mirror is located on a primary mirror reflected light path.

The tertiary mirror is located on a secondary mirror reflected light path. The detector located on a tertiary mirror reflected light path. The primary mirror and the tertiary mirror have a same fifth-order polynomial freeform surface expression. The primary mirror reflected light path, the secondary mirror reflected light path and the tertiary mirror reflected light path overlap with each other.

An image display device according to an aspect of the present technology includes an emission portion, a transparent base material, an irradiation target, and an optical portion. The emission portion emits image light along a predetermined axis. The transparent base material includes a tapered surface having a tapered shape along the predetermined axis. The irradiation target is disposed at at least a part around the predetermined axis along the tapered surface. The optical portion controls an incident angle of the image light on the irradiation target, the image light having been emitted from the emission portion, the optical portion being disposed in a manner that the optical portion faces the emission portion on the basis of the predetermined axis.

A laser beam combining device includes: a plurality of shaping optical units which emit circular laser beams which are different from each other in a change amount of an outer diameter per unit travel distance, wherein the plurality of shaping optical units are placed in such a manner that the circular laser beams emitted from the shaping optical units have a concentric shape.

An optical delay device comprises a multi-pass optical cell including first and second facing curved mirrors defining an optical cavity. One curved mirror includes a spatially extended aperture, such as a wedge-shaped notch aperture formed into the perimeter of the curved mirror. One curved mirror is split into two component mirrors one of which is tilted to define a swirling reflection pattern on the curved mirror that includes the spatially extended aperture. The optical time delay introduced to a light ray by the multi-pass optical cell depends on the input location of the light ray into the spatially extended aperture. The optical delay device may include two such multi-pass optical cells and a mirror that optically couples the two said multi-pass optical cells.

A catheter system for optical coherence tomography includes an elongate catheter body, an optical fiber in the elongate catheter body, and an anamorphic lens assembly coupled with a distal end of the optical fiber. The optical fiber and the lens assembly are together configured to provide a common path for optical radiation reflected from a target and from a reference interface between the distal end of the optical fiber and the lens assembly.

A catheter system for optical coherence tomography includes an elongate catheter body, an optical fiber in the elongate catheter body, and an anamorphic lens assembly coupled with a distal end of the optical fiber. The optical fiber and the lens assembly are together configured to provide a common path for optical radiation reflected from a target and from a reference interface between the distal end of the optical fiber and the lens assembly.

A floating image display device includes an image display for displaying a display image; a beam splitter for splitting light emitted from the display image into first light and second light; and a curved retroreflective sheet for retroreflecting the first light to display a floating image based on the display image at a space in air so that the floating image is seen from a predetermined reference position, wherein the image display, the beam splitter and the curved retroreflective sheet are arranged so that the first light traveling from the beam splitter to the curved retroreflective sheet is retroreflected and specularly reflected, a retroreflected light based on the first light travels from the curved retroreflective sheet via the beam splitter to the reference area and a specularly-reflected light based on the first light travels from the curved retroreflective sheet toward outside of the reference area.

A floating image display device includes an image display for displaying a display image; a beam splitter for splitting light emitted from the display image into first light and second light; and a curved retroreflective sheet for retroreflecting the first light to display a floating image based on the display image at a space in air so that the floating image is seen from a predetermined reference position, wherein the image display, the beam splitter and the curved retroreflective sheet are arranged so that the first light traveling from the beam splitter to the curved retroreflective sheet is retroreflected and specularly reflected, a retroreflected light based on the first light travels from the curved retroreflective sheet via the beam splitter to the reference area and a specularly-reflected light based on the first light travels from the curved retroreflective sheet toward outside of the reference area.

A catadioptric projection objective has a first objective part, defining a first part of the optical axis and imaging an object field to form a first real intermediate image. It also has a second, catadioptric objective part forming a second real intermediate image using the radiation from the first objective part. The second objective part has a concave mirror and defines a second part of the optical axis. A third objective part images the second real intermediate image into the image plane and defines a third part of the optical axis. Folding mirrors deflect the radiation from the object plane towards the concave mirror; and deflect the radiation from the concave mirror towards the image plane. The first part of the optical axis defined by the first objective part is laterally offset from and aligned parallel with the third part of the optical axis.

A catadioptric projection objective has a first objective part, defining a first part of the optical axis and imaging an object field to form a first real intermediate image. It also has a second, catadioptric objective part forming a second real intermediate image using the radiation from the first objective part. The second objective part has a concave mirror and defines a second part of the optical axis. A third objective part images the second real intermediate image into the image plane and defines a third part of the optical axis. Folding mirrors deflect the radiation from the object plane towards the concave mirror; and deflect the radiation from the concave mirror towards the image plane. The first part of the optical axis defined by the first objective part is laterally offset from and aligned parallel with the third part of the optical axis.