Optical system for digital holography

1 . An optical system ( 1 ) comprising at least the following components:

a first holography arrangement ( 2 ) comprising a first diffraction element ( 3 ) which is formed by a first prism arrangement ( 4 ) having at least a quadrangular base surface, wherein a lateral surface of the first prism arrangement ( 4 ) has the following lateral surface regions:

a) a first entry surface ( 31 ) for reference light ( 100 ) extending along a first entry plane ( 310 ),

b) a second entry surface ( 32 ) for object light ( 200 ) extending along a second entry plane ( 320 ), wherein the first and second entry surfaces ( 31 , 32 ) form opposite lateral surface regions of the first prism arrangement ( 4 ),

c) an exit surface ( 33 ), which extends along an exit plane ( 330 ) and through which diffracted reference light ( 102 ) and diffracted object light ( 201 ) can exit from the first diffraction element 3 ),

d) a prism surface ( 34 ) opposite to the exit surface ( 33 ), which extends along a prism plane ( 340 ),

e) an optical transmission diffraction grating arrangement ( 36 ) arranged in the first diffraction element ( 3 ) and extending along a diffraction plane ( 360 ) which intersects the first entry plane ( 310 ) between the first entry surface ( 31 ) and the exit surface ( 33 ),

wherein the transmission diffraction grating arrangement ( 36 ) of the first diffraction element ( 3 ) comprises at least a first volume phase hologram grating, and in that the first holography arrangement ( 2 ) has a first mirror ( 35 ) with a first mirror plane ( 350 ) on the side of the prism surface ( 34 ), wherein the first mirror plane ( 350 ) encloses an angle α with the diffraction plane ( 360 ) and the prism plane ( 340 ) encloses an angle 02 with the diffraction plane ( 360 ), wherein at least one of the angles α, W 2 is different from 45°, wherein the system ( 1 ) comprises a first array detector ( 37 ), comprising a two-dimensional array of detector elements, wherein the first array detector ( 37 ) is configured to detect light exiting from the exit surface ( 33 ) of the first diffraction element ( 3 ) wherein the first array detector ( 37 ) is arranged on the exit surface ( 33 ) of the first diffraction element ( 3 ).

2 . The optical system ( 1 ) according to claim 1 , wherein the base surface of the first prism arrangement ( 4 ) is a parallelogram, a rectangle, or a square.

3 . The optical system ( 1 ) according to claim 1 , wherein the first mirror ( 37 ) is arranged or formed on the prism surface ( 33 ) of the first diffraction element ( 3 ).

4 . The optical system ( 1 ) according to claim 1 , wherein the optical transmission diffraction grating arrangement ( 36 ) of the first holography arrangement comprises a second volume phase hologram grating, wherein the first and the second volume phase hologram gratings have different central wavelengths.

5 . The optical system ( 1 ) according to claim 1 , comprising a second holography arrangement ( 2 ′) having a second diffraction element ( 3 ′), which is formed by a second prism arrangement ( 4 ′) with at least a quadrangular base surface, wherein the first holography arrangement ( 2 ) and the second holography arrangement ( 2 ′) are arranged next to one another along an optical axis (OA) of the first diffraction element ( 3 ), and a lateral surface of the second prism arrangement ( 4 ′) has the following lateral surface regions:

f) a first entry surface ( 31 ′) for reference light ( 100 ) extending along a first entry plane ( 310 ′),

g) a entry entrance surface ( 32 ′) for object light ( 200 ) extending along a second entry plane ( 320 ′), wherein the first and second entry surfaces ( 31 ′, 32 ′) form opposite lateral surface regions of the second prism arrangement ( 4 ′),

h) an exit surface ( 33 ′), which extends along an exit plane ( 330 ′) and through which diffracted reference light ( 102 ) and diffracted object light ( 201 ) can exit from the second diffraction element ( 3 ′),

i) a prism surface ( 33 ′) opposite to the exit surface ( 33 ′), which extends along a prism plane ( 330 ′),

j) an optical transmission diffraction grating arrangement ( 36 ′) arranged in the second diffraction element ( 3 ′) and extending along a diffraction plane ( 360 ′) which intersects the first entry plane ( 310 ′) between the first entry surface ( 31 ′) and the exit surface ( 33 ′) of the second diffraction element ( 3 ′),

wherein the transmission diffraction grating arrangement ( 36 ′) of the second diffraction element ( 3 ′) comprises at least a first volume phase hologram grating, and in that the second holography arrangement ( 2 ′) has a second mirror ( 35 ′) with a second mirror plane ( 350 ′) on the side of the prism plane ( 340 ′), wherein the second mirror plane ( 350 ′) encloses an angle α′ with the diffraction plane ( 360 ′) and the prism plane ( 340 ′) encloses an angle ω′ 2 with the diffraction plane ( 360 ′), wherein at least one of the angles α′, ω′ 2 is different from 45°.

6 . The optical system ( 1 ) according to claim 5 , wherein the second entry surface ( 32 ) of the first diffraction element ( 3 ) is connected to the first entry surface ( 31 ′) of the second diffraction element ( 3 ′).

7 . The optical system ( 1 ) according to claim 1 , wherein the optical system ( 1 ) has, on the side of the first entry surface ( 31 ) of the first diffraction element ( 3 ), a collimator ( 5 ) for reference light ( 100 ), which has an optical axis which runs in the direction of the first entry surface ( 31 ) of the first diffraction element ( 3 ), and wherein the collimator ( 5 ) is configured to collimate reference light ( 100 ) before it enters through the first entry surface ( 31 ) of the first diffraction element ( 3 ).

8 . The optical system according to claim 6 , wherein the first diffraction element ( 3 ) is formed integrally with the first entry surface ( 31 ′) of the second diffraction element ( 3 ′) along its second entry surface ( 32 ), or wherein the second entry surface ( 32 ) of the first diffraction element ( 3 ) is adhesively bonded or welded to the first entry surface ( 31 ′) of the second diffraction element ( 3 ′).

9 . The optical system ( 1 ) according to claim 1 , wherein the optical system ( 1 ) comprises an objective lens ( 6 ) for object light ( 200 ), wherein the objective lens ( 6 ) is arranged in the optical system ( 1 ) such that object light ( 200 ) propagating from the objective lens ( 6 ) in the direction of the second entry surface ( 32 ) of the first diffraction element ( 3 ) and/or in the direction of the second entry surface ( 32 ′) of the second diffraction element ( 3 ′) is collimated when the object light ( 200 ) radiates in and/or near a focal plane of the objective lens ( 6 ) in the direction of the objective lens ( 6 ).

10 . The optical system ( 1 ) according to claim 1 , characterized in that the optical system ( 1 ) comprises the following components:

a laser light source ( 8 ) configured to provide laser light having one or more central wavelengths,

at least one first optical fiber ( 9 ), which is configured to guide the laser light of the laser light source ( 8 ) to an input aperture ( 10 ) of the collimator ( 5 ), so that the collimator ( 5 ) guides the collimated laser light in the form of reference light ( 100 ) to the first holography arrangement ( 2 ),

at least one second optical fiber ( 11 ) which is configured to guide the laser light of the laser light source ( 8 ) to an output aperture ( 12 ) of the optical system ( 1 ), from which an object ( 300 ) to be detected is to be illuminated using laser light in the form of object light ( 200 ).

11 . The optical system ( 1 ) according to claim 10 , characterized in that the optical system ( 1 ) comprises a fiber splitter ( 13 ), which is designed to split the laser light of the laser light source ( 8 ) and to couple it into the first optical fiber ( 9 ) and second optical fibers ( 11 ).

12 . The optical system ( 1 ) according to claim 1 , characterized in that the optical system ( 1 ) has an imaging optical unit ( 12 ) which is designed to project object light ( 200 ), in the form of an intensity pattern onto an object ( 300 ) to be detected, wherein the intensity pattern consists of at least one illuminated region or wherein the intensity pattern consists of a plurality of disjoint illuminated regions.

13 . The optical system ( 1 ) according to claim 1 , characterized in that the optical system ( 1 ) is designed to provide laser light which comprises wavelengths from at least two wavelength ranges, wherein a first wavelength range is arranged around a first central wavelength and comprises wavelengths in particular in the form of spectral lines which lie outside a second wavelength range, wherein the second wavelength range is arranged around a second central wavelength and comprises wavelengths in particular in the form of spectral lines.

14 . An optical system ( 1 ) comprising at least the following components: a first holography arrangement ( 2 ) comprising a first diffraction element ( 3 ) which is formed by a first prism arrangement ( 4 ) having at least a quadrangular base surface, wherein a lateral surface of the first prism arrangement ( 4 ) has the following lateral surface regions:

a) a first entry surface ( 31 ) for reference light ( 100 ) extending along a first entry plane ( 310 ),

b) a second entry surface ( 32 ) for object light ( 200 ) extending along a second entry plane ( 320 ), wherein the first and second entry surfaces ( 31 , 32 ) form opposite lateral surface regions of the first prism arrangement ( 4 ),

c) an exit surface ( 33 ), which extends along an exit plane ( 330 ) and through which diffracted reference light ( 102 ) and diffracted object light ( 201 ) can exit from the first diffraction element ( 3 ),

d) a prism surface ( 34 ) opposite to the exit surface ( 33 ), which extends along a prism plane ( 340 ),

e) an optical transmission diffraction grating arrangement ( 36 ) arranged in the first diffraction element ( 3 ) and extending along a diffraction plane ( 360 ) which intersects the first entry plane ( 310 ) between the first entry surface ( 31 ) and the exit surface ( 33 ),

wherein the transmission diffraction grating arrangement ( 36 ) of the first diffraction element ( 3 ) comprises at least a first volume phase hologram grating, and in that the first holography arrangement ( 2 ) has a first mirror ( 35 ) with a first mirror plane ( 350 ) on the side of the prism surface ( 34 ), wherein the first mirror plane ( 350 ) encloses an angle α with the diffraction plane ( 360 ) and the prism plane ( 340 ) encloses an angle 02 with the diffraction plane ( 360 ), wherein at least one of the angles α, w 2 is different from 45°, wherein the system further comprises

a second holography arrangement ( 2 ′) having a second diffraction element ( 3 ′), which is formed by a second prism arrangement ( 4 ′) with at least a quadrangular base surface, wherein the first holography arrangement ( 2 ) and the second holography arrangement ( 2 ′) are arranged next to one another along an optical axis (OA) of the first diffraction element ( 3 ), and a lateral surface of the second prism arrangement ( 4 ′) has the following lateral surface regions:

f) a first entry surface ( 31 ′) for reference light ( 100 ) extending along a first entry plane ( 310 ′),

g) a entry entrance surface ( 32 ′) for object light ( 200 ) extending along a second entry plane ( 320 ′), wherein the first and second entry surfaces ( 31 ′, 32 ′) form opposite lateral surface regions of the second prism arrangement ( 4 ′),

h) an exit surface ( 33 ′), which extends along an exit plane ( 330 ′) and through which diffracted reference light ( 102 ) and diffracted object light ( 201 ) can exit from the second diffraction element ( 3 ′),

i) a prism surface ( 33 ′) opposite to the exit surface ( 33 ′), which extends along a prism plane ( 330 ′),

j) an optical transmission diffraction grating arrangement ( 36 ′) arranged in the second diffraction element ( 3 ′) and extending along a diffraction plane ( 360 ′) which intersects the first entry plane ( 310 ′) between the first entry surface ( 31 ′) and the exit surface ( 33 ′) of the second diffraction element ( 3 ′),

wherein the transmission diffraction grating arrangement ( 36 ′) of the second diffraction element ( 3 ′) comprises at least a first volume phase hologram grating, and in that the second holography arrangement ( 2 ′) has a second mirror ( 35 ′) with a second mirror plane ( 350 ′) on the side of the prism plane ( 340 ′), wherein the second mirror plane ( 350 ′) encloses an angle α′ with the diffraction plane ( 360 ′) and the prism plane ( 340 ′) encloses an angle w′ 2 with the diffraction plane ( 360 ′), wherein at least one of the angles α′, is different from 45°, wherein the system ( 1 ) comprises a first array detector ( 37 ), comprising a two-dimensional array of detector elements, wherein the first array detector ( 37 ) is configured to detect light exiting from the exit surface ( 33 ) of the first diffraction element ( 3 ) wherein the first array detector ( 37 ) is arranged on the exit surface ( 33 ) of the first diffraction element ( 3 ).

15 . An optical system ( 1 ) comprising at least the following components: a first holography arrangement ( 2 ) comprising a first diffraction element ( 3 ) which is formed by a first prism arrangement ( 4 ) having at least a quadrangular base surface, wherein a lateral surface of the first prism arrangement ( 4 ) has the following lateral surface regions:

a) a first entry surface ( 31 ) for reference light ( 100 ) extending along a first entry plane ( 310 ),

b) a second entry surface ( 32 ) for object light ( 200 ) extending along a second entry plane ( 320 ), wherein the first and second entry surfaces ( 31 , 32 ) form opposite lateral surface regions of the first prism arrangement ( 4 ),

c) an exit surface ( 33 ), which extends along an exit plane ( 330 ) and through which diffracted reference light ( 102 ) and diffracted object light ( 201 ) can exit from the first diffraction element ( 3 ),

d) a prism surface ( 34 ) opposite to the exit surface ( 33 ), which extends along a prism plane ( 340 ),

e) an optical transmission diffraction grating arrangement ( 36 ) arranged in the first diffraction element ( 3 ) and extending along a diffraction plane ( 360 ) which intersects the first entry plane ( 310 ) between the first entry surface ( 31 ) and the exit surface ( 33 ),

wherein the transmission diffraction grating arrangement ( 36 ) of the first diffraction element ( 3 ) comprises at least a first volume phase hologram grating, and in that the first holography arrangement ( 2 ) has a first mirror ( 35 ) with a first mirror plane ( 350 ) on the side of the prism surface ( 34 ), wherein the first mirror plane ( 350 ) encloses an angle α with the diffraction plane ( 360 ) and the prism plane ( 340 ) encloses an angle W 2 with the diffraction plane ( 360 ), wherein at least one of the angles α, w 2 is different from 45°, wherein the optical system ( 1 ) has an imaging optical unit ( 12 ) which is designed to project object light ( 200 ) in the form of an intensity pattern onto an object ( 300 ) to be detected, wherein the intensity pattern consists of at least one illuminated region or wherein the intensity pattern consists a plurality of disjoint illuminated regions, wherein the system ( 1 ) comprises a first array detector ( 37 ), comprising a two-dimensional array of detector elements, wherein the first array detector ( 37 ) is configured to detect light exiting from the exit surface ( 33 ) of the first diffraction element ( 3 ) wherein the first array detector ( 37 ) is arranged on the exit surface ( 33 ) of the first diffraction element ( 3 ).