Device and Method for Generating Optical Tweezers

Abstract

The present invention relates to a device (10) for generating optical tweezers comprising a laser beam source (11) for generating a laser beam (12) and at least one acousto-optic deflector (13) for generating an array (15) of partial beams (14) of the laser beam (12), wherein the array (15) comprises rows (15c). The device (10) further comprises a stepped mirror unit (16) comprising at least a first stepped mirror (25) for reducing a row distance (15d) of the partial beams (14) of the array (15), wherein the first stepped mirror (25) comprises mirrors (30), a stepped distance (25a) between adjacent mirrors (30) and a stepped height (25b).

Claims

1. Device for generating optical tweezers, wherein a laser beam source for generating a laser beam, and at least one acousto-optic deflector for generating an array of partial beams of the laser beam, wherein the array comprises rows, wherein the device has a stepped mirror unit comprising at least one first stepped mirror for reducing a row distance of the partial beams of the array, wherein the first stepped mirror comprises mirrors, a stepped distance between adjacent mirrors and a stepped height.

2. Device according to claim 1, wherein the stepped mirror unit is multi-stage, preferably two- or three-stage.

3. Device according to claim 1, wherein the stepped mirror unit comprises a second stepped mirror, wherein the second stepped mirror comprises mirrors, a stepped distance between adjacent mirrors and a stepped height, wherein the stepped distance of the second stepped mirror corresponds to the stepped height of the first stepped mirror.

4. Device (10) according to claim 3, wherein the stepped mirror unit comprises a third stepped mirror, wherein the third stepped mirror comprises mirrors, a stepped distance between adjacent mirrors and a stepped height, wherein the stepped distance of the third stepped mirror corresponds to the stepped height of the second stepped mirror.

5. Device (10) according to claim 1, wherein the device comprises a coupling unit for coupling the partial beams into the stepped mirror unit, wherein the coupling unit comprises mirrors, a stepped distance between adjacent mirrors and a stepped height, wherein the stepped height of the coupling unit corresponds to the stepped distance of the first stepped mirror.

6. Device according to claim 1, wherein the stepped height of the first stepped mirror is smaller than the stepped distance of the first stepped mirror and/or the stepped height of the second stepped mirror is smaller than the stepped distance of the second stepped mirror and/or the stepped height of the third stepped mirror is smaller than the stepped distance of the third stepped mirror, and/or the stepped height of the coupling unit is smaller than the stepped distance of the coupling unit.

7. Device according to claim 1, wherein the stepped distance of the first stepped mirror is between 4 mm and 12 mm, preferably between 6 mm and 10 mm, most preferably between 7 mm and 9 mm, and/or the stepped height of the first stepped mirror is between 0.5 mm and 3.5 mm, preferably between 1 mm and 3 mm.

8. Device according to claim 3, wherein the stepped distance of the second stepped mirror is between 0.5 mm and 3.5 mm, preferably between 1 mm and 3 mm, and/or the stepped height of the second stepped mirror is between 0.25 mm and 0.75 mm, preferably between 0.4 mm and 0.6 mm.

9. Device according to claim 4, wherein the stepped distance of the third stepped mirror is between 0.25 mm and 0.75 mm, preferably between 0.4 mm and 0.6 mm, and/or the stepped height of the third stepped mirror is between 0.10 mm and 0.30 mm, preferably between 0.150 mm and 0.20 mm.

10. Device according to claim 1, wherein the device comprises a beam splitter unit for splitting the laser beam into partial beams in a first direction, wherein the device comprises one acousto-optic deflector per partial beam for dividing the partial beams into rows and thus for generating the array of partial beams.

11. Device according to claim 1, wherein the device comprises relay optics comprising a microscope objective for reducing the row distance and the distance of partial beams within a row, wherein the partial beams after the relay optics form optical tweezers for capturing atoms.

12. Device according to claim 1, wherein the device has a unit for coupling radiation to excite atoms captured by means of the optical tweezers and/or for decoupling radiation originating from atoms captured by means of the optical tweezers, wherein the unit is configured for coupling and/or decoupling in a pupil plane of the relay optics.

13. Method for generating optical tweezers, wherein the method comprises generating an array of partial beams by means of at least one acousto-optic deflector, wherein the array comprises rows, wherein the method comprises a reduction of a row distance of the partial beams of the array by means of a stepped mirror unit having at least a first stepped mirror, wherein the first stepped mirror comprises mirrors, a stepped distance between adjacent mirrors and a stepped height.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0057] The figures show in a purely schematic representation:

[0058] FIG. 1: a device for generating optical tweezers;

[0059] FIG. 2: an array of partial beams,

[0060] FIG. 3: a detailed view of the device of FIG. 1, and

[0061] FIG. 4: an enlarged view of the stepped mirror unit of FIG. 3; and

[0062] FIG. 5: a process diagram of a method for generating optical tweezers.

PREFERRED EMBODIMENTS

[0063] FIG. 1 shows a schematic representation of a device 10 for generating optical tweezers. The device 10 comprises a laser beam source 11 which couples out a laser beam 12. Furthermore, the device 10 comprises several acousto-optic deflectors 13, a beam splitter unit 13a, which splits the laser beam 12 into a plurality of partial beams 14, in this example a column 15a, and a plurality of acousto-optic deflectors 13b for splitting the partial beams 14 into rows 15c. The rows 15c run in the image plane so that the individual partial beams cannot be seen in FIG. 1. The result is an array 15 of partial beams 14.

[0064] Fourier lenses 33 are also shown schematically. Each row of the array 15 is assigned its own Fourier lens 33. Furthermore, a coupling unit 29 is shown, after which the partial beams 14 of the array 15 pass through the stepped mirror unit 16. This is followed by a relay optics 40, after which the partial beams 14 form optical tweezers.

[0065] FIG. 2 shows the array 15 of partial beams 14 in the first direction 50 and the second direction 51. The third direction 52, in which the partial beams propagate, extends into the image plane. In the example of FIG. 2, the partial beams 14 are arranged in columns 15a with a distance 15b between partial beams in a row and rows 15c with a row distance 15d.

[0066] Section 2A shows how the row distance 15d is significantly greater than the distance 15b of partial beams in a row. This is due in particular to the size of the acousto-optic deflectors 13b. As shown in section 2A, the array 15 is present after the Fourier lenses, especially in the focal plane of the Fourier lenses, if no stepped mirror unit is used.

[0067] In section 2B, the array 15 is present after passing through the stepped mirror unit 16. More precisely, the array is present in the focal plane of the Fourier lenses when the stepped mirror unit 16 is used. The row distance 15d is significantly reduced. It now corresponds to the distance 15b of adjacent partial beams in a row.

[0068] In section 2C of FIG. 2, the distance 15d of the partial beams in a row and the row distance 15d after passing through the relay optics 40 is reduced again, preferably by a factor of 50 compared to section 2B.

[0069] FIG. 3 shows a more detailed view of the device 10 in FIG. 1. While the beam splitter unit is not visible, the acousto-optic deflectors 13b and the Fourier lenses 33 can be seen. A Fourier lens 33 is assigned to each row of the array 15. At the position of the Fourier lenses 33, the first direction 50 of the array in FIG. 3 runs horizontally, while the second direction 51 runs vertically. The beams shown in FIG. 3 after the acousto-optic deflectors 13 are columns 15a of the array 15. Thus the row distance 15d can be seen. The distance 15b of partial beams in a row is so much smaller in comparison that it cannot be seen in FIG. 3.

[0070] FIG. 3 shows only the ten lowest rows 15c of the array 15, which are coupled on one side of the stepped mirror unit 16. Further rows 15c of the array 15 are coupled on the other side of the stepped mirror unit 16, which is described in more detail below.

[0071] The partial beams 14 pass through the Fourier lenses 33 and then hit the coupling unit 29, which consists of several mirrors 30. The coupling unit 29 is characterized by a fixed stepped distance 29a and a fixed stepped height 29b. The mirrors 30 are thus each offset by a step height 29b and a step distance 29a.

[0072] The stepped mirror unit 16 is shown in greater detail in the upper right section of FIG. 3. As can be seen, the stepped mirror unit 16 consists of three components, namely a first component 17, a second component 18 and a third component 19, which are formed wedge-shaped. The end areas, in which they taper to a point, face each other. The first component 17 is formed mirror-symmetrically.

[0073] The first component 17 has a first side surface 17a and a second side surface 17b. A first stepped mirror 25 is arranged on each of the two aforementioned side surfaces with mirrors 30 and a stepped distance 25a between adjacent mirrors 30 and a stepped height 25b (see upper section of FIG. 3 and FIG. 4).

[0074] The second component 18 has a first side surface 18a, which is opposite the first side surface 17a of the first component 17. Furthermore, the third component 19 has a first side surface 19a, which is opposite the second side surface 17b of the first component 17. The first side surface 18a of the second component 18 and the first side surface 19a of the third component 19 each have a second stepped mirror 26 with a stepped distance 26a and a stepped height 26b between mirrors 30 (see also the lower section of FIG. 3 and FIG. 4).

[0075] Another even more detailed representation can be seen in the lower detailed representation of FIG. 3. The mirrors 30 of the second stepped mirrors 26 on the second component 18 and the third component 19 can be seen more clearly. It can also be seen how the first component 17 has a first end region 17c. In the first end region 17c of the first component 17, a third stepped mirror 27 is arranged on each of the two side surfaces of the first component 17 with a stepped distance 27a and a stepped height 27b.

[0076] The relay optics 40, which consists of two collimators 40a and a focusing lens group 40b arranged between them, follows the stepped mirror unit 16. Furthermore, the relay optics 40 comprises a microscope objective 40c. A decoupling mirror 41 is arranged between the second collimator 40a and the microscope objective 40c. The decoupling mirror 41 lies in a pupil plane 42, which is optimally suited for coupling radiation to excite trapped atoms or for decoupling radiation from trapped atoms. A second intermediate image plane 43 can be arranged after the lens group 40b.

[0077] The row distance 15d of the partial beams was initially reduced by means of the stepped mirror unit 16 and the coupling unit 29. A further reduction of both the row distance 15d and also the distance 15b of partial beams in a row then takes place via the relay optics 40 by means of the microscope objective 40c, among other things.

[0078] FIG. 4 shows an enlarged view of the stepped mirror unit 16 from FIG. 3. The first component 17 with first stepped mirrors 25 arranged on both sides can be clearly seen on the respective side surfaces 17a, 17b. Furthermore, three mirrors 30 of the coupling unit 29 can be seen. Their stepped distance 29a and their stepped height 29b can be clearly seen.

[0079] Due to the offset arrangement of the mirrors 30 of the coupling unit 29, these represent a stepped mirror. Furthermore, the second component 18 and the third component 19 of the stepped mirror unit 16 can be seen, which have a second stepped mirror 26 on the respective first side surfaces 18a, 19a. In the enlarged representation on the right-hand side of FIG. 4, the first end region 17c of the first component 17 can be clearly seen in particular. A third stepped mirror 27 with the stepped distance 27a and the stepped height 27b is arranged on each of the side surfaces 17a and 17b.

[0080] FIG. 5 shows a method diagram of a method 100 for generating optical tweezers, comprising generating 103 an array 15 of partial beams 14 and reducing 106 a row distance 15d of the array, in other words the distance of the partial beams of the array 15 in at least a first direction 50.

[0081] First, the method 100 can comprise splitting 101 the laser beam 12 of a laser beam source 11 into partial beams 14 in a first direction and then splitting 102 the partial beams thus generated in a second direction 51 and thus into rows 15c. In this way, the array 15 is generated 103.

[0082] Subsequently, the partial beams 14 of the array 15 can be coupled 104 into the stepped mirror unit 16 and pass through 105 the stepped mirror unit 16. In this way, the row distance 15d of the partial beams 14 is reduced 106. A further reduction 108 of the distance of the partial beams 14 of the array 15 in both directions is achieved in particular by passing 107 through a relay optics 40.

REFERENCE NUMBERS

[0083] 10 device [0084] 11 laser beam source [0085] 12 laser beam [0086] 13 acousto-optic deflector [0087] 13a beam splitter unit [0088] 13b acousto-optic deflector [0089] 14 partial beams [0090] 15 array [0091] 15a column [0092] 15b distance within a row [0093] 15c row [0094] 15d row distance [0095] 16 stepped mirror unit [0096] 17 first component [0097] 17a first side surface of the first component [0098] 17 second side surface of the first component [0099] 17c first end portion of the first component [0100] 18 second component [0101] 18a first side surface of the second component [0102] 19 third component [0103] 19 first side surface of the third component [0104] 25 first stepped mirror [0105] 25a stepped distance of the first stepped mirror [0106] 25b stepped height of the first stepped mirror [0107] 26 second stepped mirror [0108] 26a stepped distance of the second stepped mirror [0109] 26b stepped height of the second stepped mirror [0110] 27 third stepped mirror [0111] 27a stepped distance of the third stepped mirror [0112] 27b stepped height of the third stepped mirror [0113] 29 coupling unit [0114] 29a stepped distance of the coupling unit [0115] 29b stepped height of the coupling unit [0116] 30 mirror [0117] 33 Fourier lenses [0118] 40 relay optics [0119] 40a collimator [0120] 40b focusing lens group [0121] 40c microscope objective [0122] 41 decoupling mirror [0123] 42 pupil level [0124] 43 second intermediate image plane [0125] 50 first direction [0126] 51 second direction [0127] 52 third direction [0128] 100 method for generating optical tweezers [0129] 101 splitting the laser beam into partial beams in a column [0130] 102 splitting the partial beams into rows [0131] 103 generating an array of partial beams [0132] 104 coupling the partial beams of the array into the stepped mirror unit [0133] 105 passing through the stepped mirror unit [0134] 106 reduction of a row distance of the partial beams of the array [0135] 107 passing through the relay optics [0136] 108 reduction of the row distance and distance of the partial beams in a row