DE102010029062B4 - Optical system, data transmission system and system for the acquisition of electromagnetic radiation - Google Patents

Abstract

Optical system (100) for focusing electromagnetic radiation onto a detection unit (E), the optical system (100) having a mirror system (SP), characterized in that
- that the optical system (100) has a first lens unit (L1) and at least one detection unit (E),
- That from the first lens unit (L1) in the direction of the detection unit (E) a second lens unit (L2), the mirror system (SP), a third lens unit (L3) and a fourth lens unit (L4) are arranged, and
- That the mirror system (SP) is integrally formed and has two outer surfaces (5,8).

Description

The invention relates to an optical system for focusing electromagnetic radiation onto a detection unit, the optical system having a mirror system. The invention also relates to a data transmission system and a system for the acquisition of electromagnetic radiation.

From the DE 197 29 245 C1 a mirror lens for focusing electromagnetic radiation by means of reflection and light transmission surfaces is known. Incident electromagnetic radiation is admitted through a light passage opening of the mirror objective. The electromagnetic radiation is reflected on a mirror surface in the direction of a further mirror surface and from there in the direction of a light transmission surface, where it emerges from an outside of an optical element and is focused into a focus. The known mirror lens is intended for the analysis of molecules.

However, the present invention is intended to be used in a completely different field, namely in the communication between two locations that are at a distance from one another. Basically, it's about data exchange from a first location A to a second place B , wherein the data exchange takes place by means of electromagnetic radiation. This communication takes place, for example, between two satellites in space or a satellite and a corresponding earth station on earth. Here, a distance of, for example, 200 km to 36,000 km has to be covered. The known mirror objective mentioned above is not suitable for this, because it is selected such that a sample can be examined with it. For this purpose, the known mirror lens is arranged quite close to the sample. For example, it is used in a scanning microscope. This means that only very short distances from the electromagnetic radiation can be covered. The known mirror lens is not designed for electromagnetic radiation from large distances.

It is obvious that when communicating between places further away from each other A and B , for example two satellites or a satellite and a ground station, from which electromagnetic radiation has to be covered long distances before the electromagnetic radiation from the first location A to the second place B arrives. Electromagnetic radiation that travels a long distance should be focused when it is in the second location B arrives so that it is on a registration unit at the second location B how a CCD can be conducted.

The invention is also intended to be used in the field of the acquisition of electromagnetic radiation. This is understood to mean the alignment of a recording system in such a way that incident electromagnetic radiation runs centrally in a recording system (small field of view angle essentially from 0 ° to 0.5 °). As a rule, this is achieved in that a first scanning mirror, which is arranged in front of the optical system, directs the radiation to the optical system. Using a second scanning mirror, a small field of view angle (for example in the range from 0 ° to 0.5 °) is then brought about for the optical system. The known mirror lens mentioned above is also unsuitable for an acquisition.

In the DE 824 558 B a Cassegrain type mirror lens objective with spherical mirrors is specified, two correction elements formed from two spherical lenses standing close to each other being provided, one of which is in front of the collecting mirror, the other of which is behind the scattering mirror, each correction element also having zero refractive power and all of them Lenses are made of the same type of glass.

The DE 1 873 356 U. relates to a Cassegrain type mirror objective with two spherical mirrors, of which the secondary mirror has the greater curvature, and two correction systems formed from two closely spaced spherical lenses are connected upstream or downstream, the lenses of the front and rear correction systems each consisting of different ones Glass types exist, and the front correction system is afocal, its focal length is greater than 150 times the lens focal length, while the rear correction system has a negative refractive power such that the absolute amount of its focal length is smaller than that 1 . 5 times the focal length of the lens.

The invention is therefore based on the object of specifying an optical system which is suitable for transmitting electromagnetic radiation between two spaced-apart locations and which enables adequate focusing of the electromagnetic radiation and acquisition of electromagnetic radiation.

This object is achieved according to the invention by an optical system with the features of claim 1. A data transmission system according to the invention is characterized by the features of claim 17 described. A system for the acquisition of electromagnetic radiation is described by the features of claim 18. Further features of the invention result from the further claims, the following description and / or the attached figures.

According to the invention, the optical system for focusing electromagnetic radiation on a detection unit is provided. The optical system is provided with a mirror system and with a first lens unit, wherein above and also below a lens unit is understood to mean either a single lens or a lens system comprising a plurality of lenses. In addition to the first lens unit, at least one detection unit is provided in the optical system according to the invention, the detection unit being designed, for example, as a CCD. However, it is pointed out that the invention is not restricted to such a detection unit. Rather, any detection unit that is suitable for the invention can be used for the detection unit. A second lens unit, the mirror system, a third lens unit and a fourth lens unit are arranged from the first lens unit in the direction of the detection unit. In other words, the optical system from the first lens unit in the direction of the detection unit has the following sequence of arrangement of the individual structural units of the optical system: first lens unit - second lens unit - mirror system - third lens unit - fourth lens unit - detection unit. According to the invention, it is also provided to design the mirror system as a monolithic mirror system.

The optical system according to the invention is a catadiotropic system which has a very compact structure and is light in weight. Considerations have shown that the optical system according to the invention is particularly well suited for focusing electromagnetic radiation and in particular for communication between two locations, with electromagnetic radiation being transmitted. In addition, the use of a monolithic mirror system is particularly advantageous since the manufacture of such a mirror system is simple and also ensures that the overall length of the optical system according to the invention can be short.

Furthermore, the optical system according to the invention is suitable for the acquisition of electromagnetic radiation, which has already been explained in more detail above.

According to a first embodiment of the optical system according to the invention, the first lens unit, the second lens unit, the third lens unit and / or the fourth lens unit each consist of a single lens. The embodiment in which each of the aforementioned lens units consists of only a single lens is particularly preferred. The aforementioned embodiments have the advantage that the weight of the optical system can be kept low. Furthermore, the manufacturing costs of the optical system are reduced due to the small number of units used. However, it is expressly pointed out that the invention is not restricted to the fact that the aforementioned lens units consist of only a single lens. Rather, embodiments are also provided in which at least one of the aforementioned lens units has more than one lens or at least one lens composed of a plurality of lenses (for example a cemented member).

In a further embodiment of the invention, the first lens unit has an entry surface (ie a first entry surface) and an exit surface (ie a first exit surface) for electromagnetic radiation. The entry surface (ie a first entry surface) and / or the exit surface (ie the first exit surface) of the first lens unit is / are spherical. As an alternative or in addition to this, it is provided that the second lens unit, the third lens unit and the fourth lens unit each have an entrance surface and an exit surface for electromagnetic radiation. In other words, the second lens unit has a second entrance surface and a second exit surface, the third lens unit has a third entrance surface and a third exit surface, and the fourth lens unit has a fourth entrance surface and a fourth exit surface for electromagnetic radiation. Furthermore, in this preferred exemplary embodiment, it is provided that both the entry surface and the exit surface of each of the aforementioned lens units are spherical.

According to a further preferred exemplary embodiment of the optical system according to the invention, the optical system has a diaphragm unit which, starting from the first lens unit, is arranged in the opposite direction to the detection unit.

In a further exemplary embodiment of the invention, the optical system is provided with an image angle in the range from -1.7 ° to 1.7 °, preferably in the range from -1.5 ° to 1.5 °, the specified limit values of the ranges in preferred range are included. Considerations have shown that this Property is particularly well suited for focusing electromagnetic radiation between two distant locations.

Preferred exemplary embodiments preferably have a specific focal length and a specific overall length. In a further exemplary embodiment of the invention, it is provided that the optical system has a focal length in the range from 250 mm to 300 mm, preferably in the range from 260 mm to 290 mm, the specified limit values of the ranges being contained in the preferred range. In addition, it is provided that the distance between the first lens unit and the detection unit is preferably in the range from 40 mm to 70 mm, preferably in the range from 50 mm to 60 mm. Here too the limit values are in the preferred range. The distance between the first lens unit and the detection unit defines the overall length of the optical system according to the invention.

Since the invention is to be used, for example, for communication between two satellites in space or a satellite and a ground station, it is preferably provided that the first lens unit, the second lens unit, the third lens unit and / or the fourth lens unit are formed from a radiation-resistant glass is / are. Radiation-resistant glass is understood here to be a glass whose material resistance is not damaged due to incident radiation and whose properties do not change or change only slightly due to incident radiation. Radiation-resistant glasses are particularly well suited for the purpose already mentioned above. Examples of radiation-resistant glasses are, for example, the glasses BK7G18, SK5G06 and SF5G10. The glasses mentioned below are also suitable for this purpose.

In a further embodiment of the optical system according to the invention, the mirror system has two outer surfaces, namely a first outer surface and a second outer surface. The first outer surface is directed towards the first lens unit, while the second outer surface is directed towards the detection unit. In addition, the mirror system is preferably provided with two mirror surfaces, namely a first mirror surface and a second mirror surface. In this embodiment, the first mirror surface is assigned to the second outer surface, while the second mirror surface is assigned to the first outer surface. With regard to the definition of assignment, reference is made to below. As an alternative or in addition to this, it is provided that the first lens unit, the second lens unit, the third lens unit, the fourth lens unit and the mirror system have the following properties, the properties being standardized to the optical system with a focal length of f = 286 mm: area radius Distance [mm] Glass First surface of the first lens unit 49.04640 4.87339 LAK9G15 Second surface of the first lens unit 21.91030 5.96210 First surface of the second lens unit 36.81300 3.18699 K5G20 Second surface of the second lens unit 4302.0000 2.58957 First outer surface of the mirror system infinitely 15.52 BK7G18 First mirror surface of the mirror system -36.25680 -15.13957 mirror material Second mirror surface of the mirror system -7.50000 15.13957 mirror material Second outer surface of the mirror system -36.25680 2.01599 First surface of the third lens unit -4.21700 2.31110 LAK9G15 Second surface of the third lens unit 36.02700 2.55137 First surface of the fourth lens unit -4.9400 4.60000 LF5G15 Second surface of the fourth lens unit -6.38900

The individual surfaces of the lens units and their radii are given in the table above. Furthermore, the distance from the vertex of a first surface to the vertex of the next surface is specified. The distance also reflects the thickness of the individual lens units and the mirror system. The type of glass of the respective lens units and the mirror system is also given, the notation of the glass types referring to the glass types from the Schott company. The mirror surfaces are formed from a reflective material (mirror material), for example silver in the form of a silver layer. The above table was generally created for a spectral range from 400nm to 1200nm.

As mentioned above, the properties given in the table are standardized to an optical system with a focal length of f = 286 mm. By multiplying the radii and distances by a factor, the properties can be converted proportionally to other focal lengths.

In a further embodiment of the optical system according to the invention, the respective entry surface (s) and exit surface (s) of the first lens unit, the second lens unit, the third lens unit and / or the fourth lens unit are each provided with an antireflection layer, so that a transmission of greater than or equal to 99.7% for electromagnetic radiation with a wavelength in the range from 550 nm to 580 nm and a transmission of greater than or equal to 90% for electromagnetic radiation with a wavelength of essentially 1064 nm are achieved. As an alternative or in addition to this, it is provided that the first outer surface and the second outer surface of the mirror system are provided with an antireflection layer, so that a transmission of substantially greater than or equal to 99.7% is achieved. Furthermore, it is preferably provided to provide the first mirror surface and the second mirror surface of the mirror system with a silver layer, so that a reflection of substantially greater than or equal to 97% is achieved. The aforementioned values relate to the transmission or reflection of the individual surfaces mentioned. The transmission of the entire optical system is greater than or equal to 75%.

In a preferred embodiment, the optical system is athermal. In other words, the optical system is composed independent of temperature, so that it is particularly suitable for use in space. Temperature influences, in particular temperature fluctuations in a range of ± 20 ° C or of ± 50 ° C around a standard temperature (e.g. room temperature or 0 ° C, whereby the standard temperature is not restricted to the aforementioned values) therefore do not influence the functionality of the optical system. In addition, it is advantageous to design the optical system to be insensitive to shock loads, for example to large acceleration forces when a launch vehicle is launched. This ensures the proper functioning of the optical system according to the invention. The training against shock loading takes place, for example, in that the optical system is designed to be weight-symmetrical. This means that the center of gravity of the optical system is arranged as far as possible in the middle of the optical system. This enables as few parts of the optical system as possible to be set into oscillations of large amplitude, which could impair the functionality of the optical system.

The invention also relates to a data transmission system for the transmission of data between two locations, which has at least one optical system which has at least one of the above-mentioned features or a combination of the above-mentioned features.

The invention also relates to a system for acquiring electromagnetic radiation which is provided with an optical system which has at least one of the features mentioned above or a combination of the features mentioned above. This ensures alignment of a recording system in such a way that electromagnetic radiation runs as centrally as possible in a recording system (for example a camera) (cf. also the above statements).

• 1 eine schematische Darstellung einer Ausführungsform eines optischen Systems mit vier Linseneinheiten;
• 2 eine schematische Darstellung des optischen Systems nach 1, wobei eine Blende vorgesehen ist;
• 3 schematische Darstellungen der Aberration des optischen Systems nach 1;
• 4 eine schematische Darstellung der Beugungs-Modulationstransferfunktion für das optische System gemäß 1; und
• 5 eine schematische Darstellung eines Datenübertragungssystems mit zwei Satelliten, die jeweils mit einem optischen System gemäß der 1 versehen sind.

The invention is described in more detail below using an exemplary embodiment. Show

• 1 a schematic representation of an embodiment of an optical system with four lens units;
• 2 is a schematic representation of the optical system 1 , wherein an aperture is provided;
• 3 schematic representations of the aberration of the optical system according to 1 ;
• 4 a schematic representation of the diffraction modulation transfer function for the optical system according to 1 ; and
• 5 a schematic representation of a data transmission system with two satellites, each with an optical system according to the 1 are provided.

The 1 shows an optical system 100 according to the present invention. The optical system 100 has four lens units, namely a first lens unit L1 , a second lens unit L2 , a third lens unit L3 and a fourth lens unit L4 , Furthermore, the optical system 100 with a mirror system SP and with a registration unit e Mistake. The order of the individual aforementioned units of the optical system 100 from the first lens unit L1 to the registration unit e is as follows: first lens unit L1 - second lens unit L2 - mirror system SP - third lens unit L3 - fourth lens unit L4 - registration unit e , Between the fourth lens unit L4 and the registration unit e , for example a CCD, is a filter element F arranged.

In the illustrated embodiment, the first lens unit L1 , the second lens unit L2 , the third lens unit L3 and the fourth lens unit L4 each composed of a single lens, so that the number of lenses of the optical system 100 is limited to a total of four. However, the invention is not restricted to this number or to the use of individual lenses. Reference is made to the statements made earlier. Each lens unit L1 to L4 is provided with an entrance area and an exit area for electromagnetic radiation. So the first lens unit points L1 a first entrance area 1 and a first exit surface 2 on. The second lens unit L2 is with a second entrance area 3 and with a second exit surface 4 Mistake. The third lens unit L3 in turn is with a third entrance area 9 and with a third exit surface 10 Mistake. The fourth lens unit L4 on the other hand is with a fourth entrance area 11 and with a fourth exit surface 12 Mistake. In the following and above, the individual entry and exit areas are also referred to as “areas”, followed by their associated reference symbols.

The first entry area 1 and the first exit surface 2 the first lens unit L1 are spherical. The entrance surface and exit surface of each of the further lens units L2 . L3 and L4 are also spherical.

The mirror system SP is designed as a monolithic mirror system. It is therefore made in one piece. The mirror system SP has two outer surfaces, namely a first outer surface 5 and a second outer surface 8th , The first outer surface 5 is to the first lens unit L1 directed. In contrast, the second outer surface 8th to the registration unit e directed. The first outer surface 5 is a second mirror surface 7 assigned during the second outer surface 8th a first mirror surface 6 assigned. An assignment of the mirror surface to the outer surface is understood to mean, for example, an arrangement of the mirror surface on the outer surface.

For example, the first outer surface 5 a first outer section 5a and a second outer section 5b on. Both the first outer section 5a as well as the second outer section 5b are provided with an anti-reflective layer, so that a transmission of essentially 99.7% is achieved for electromagnetic radiation with a wavelength in the range from 550 nm to 580 nm. Between the first outer section 5a and the second outer section 5b is a first mirror section 5c the second mirror surface 7 arranged. The first mirror section 5c is provided with a silver layer, so that a reflection of the electromagnetic radiation is essentially achieved by 97%. In a further exemplary embodiment it is provided that the first mirror section 5c is first provided with a reflective silver layer, over which in turn an anti-reflective layer is arranged. This ensures that also in the area of the first mirror section 5c electromagnetic radiation in the mirror system SP can occur. In yet another embodiment, it is provided in the area of the first mirror section 5c to apply an anti-reflective layer, which is for electromagnetic radiation coming from the direction of the first lens unit L1 comes, transmits, and which for electromagnetic Radiation coming from the direction of the third lens unit L3 comes, has a reflective effect. All of the aforementioned layers are applied to the mirror system, for example, by vapor deposition SP applied.

A similar structure is for the second outer surface 8th intended. So the second outer surface 8th a second mirror section 8a and a third mirror section 8b the first mirror surface 6 on. Both the second mirror section 8a as well as the third mirror section 8b are provided with a silver layer, so that a reflection of the electromagnetic radiation, which comes from the direction of the first outer surface 5 comes, is essentially achieved by 97%. Between the second mirror section 8a and the third mirror section 8b is a third outer section 8c arranged. This is provided with an anti-reflective layer, so that a transmission of essentially 99.7% is achieved for the electromagnetic radiation with a wavelength in the range from 550 nm to 580 nm, which comes from the direction of the first outer surface 5 comes. All of the aforementioned layers are, for example, in turn deposited on the mirror system SP applied.

The following is a table of properties of the first lens unit L1 , the second lens unit L2 , the third lens unit L3 , the fourth lens unit L4 , the mirror system SP , the filter F and the registration unit e specified. unit area radius Distance [mm] Glass L1 Area 1 49.04640 4.87339 LAK9G15 Area 2 21.91030 5.96210 L2 Area 3 36.81300 3.18699 K5G20 Area 4 4302.0000 2.58957 SP Area 5 infinitely 15.52 BK7G18 Area 6 -36.25680 -15.13957 mirror material Area 7 -7.50000 15.13957 mirror material Area 8 -36.25680 2.01599 L3 Area 9 -4.21700 2.31110 LAK9G15 Area 10 36.02700 2.55137 L4 Area 11 -4.9400 4.60000 LF5G15 Area 12 -6.38900 5.73850 F Area 13 infinitely 1.0000 BK7G18 Area 14 infinitely 0.10305 e Area 15 infinitely

The properties listed in the table above apply to an optical system 100 with a focal length of f = 286 mm. The individual areas of the individual lens units are also shown in the table above L1 to L4 (areas 1 to 4 such as 9 to 12 ), the mirror system SP (first outer surface 5 , second outer surface 8th , first mirror surface 6 , second mirror surface 7 ), the filter element F (areas 13 and 14 ) and the registration unit e (Area 15 ). The radii of the individual surfaces are also given. In addition, the distance from the vertex of a first surface to the vertex of the next surface is specified. This also gives the thickness of the individual lens units L1 to L4 , the mirror system SP and the filter element F again. The glass type of the respective units is also given, the notation of the glass types referring to Schott glass types. The table was generally created for a spectral range from 400nm to 1200nm.

As mentioned above, the properties stated are on an optical system 100 standardized with a focal length of f = 286 mm. By multiplying the radii and distances by a factor, the properties can be converted proportionally to other focal lengths.

That in the 1 illustrated optical system 100 has an overall length of 50.5 mm. This is the distance between the first lens unit L1 to the registration unit e , The distance is the distance between the apex of a first surface (here the entrance surface 1 the first lens unit L1 ) and the Vertex of a second surface (entry surface 15 the registration unit e ). If no vertex is formed on one of the surfaces (in the case of a flat surface), then the plane is used to determine the distance.

The optical system 100 is also designed so that a ratio of length to focal length of 0.175 is achieved. In addition, the optical system has an angle of view in the range of -1.7 ° to 1.7 °, for example -1.5 ° to 1.5 °. A range from - 1.544 ° to 1.544 ° is particularly preferred.

The optical system 100 is athermally trained. It is therefore insensitive to changes in temperature. Temperature influences, in particular temperature fluctuations in a range of ± 20 ° C or of ± 50 ° C around a standard temperature (for example room temperature or 0 ° C, the standard temperature not being limited to the aforementioned values) therefore influence the functionality of the optical system 100 Not. All types of glass are radiation-resistant glasses, making the optical system 100 can be used in space.

Furthermore, the optical system 100 insensitive to shock loads. The training against shock loading takes place, for example, in that the optical system 100 is formed weight-symmetrical. This means that the focus of the optical system 100 if possible in the middle of the optical system 100 is arranged. This enables as few parts of the optical system as possible 100 vibrated of large amplitude, which is the functionality of the optical system 100 could affect.

The formation of the optical system described above 100 (or structure of the optical system 100 ) is also compact, so that even a low weight is achieved.

The first lens unit L1 , the second lens unit L2 , the third lens unit L3 and the fourth lens unit L4 are each provided with an anti-reflective coating. A transmission of greater than or equal to 99.7% is achieved for electromagnetic radiation with a wavelength in the range from 550 nm to 580 nm. Furthermore, a transmission of greater than or equal to 90% is achieved for electromagnetic radiation with a wavelength of essentially 1064 nm. The aforementioned properties each relate to one of the surfaces of the aforementioned lens units.

According to the 2 is the optical system 100 to 1 an aperture BL upstream, the distance from the first lens unit L1 in to the registration unit e opposite direction is approx. 128 mm. With regard to the definition of the distance, reference is made to above.

The optical system 100 becomes, for example, for communication between a first satellite A and a second satellite B used in space. This is in 5 shown in more detail. Both the first satellite point A as well as the second satellite B one optical system each 100 according to the 1 to receive electromagnetic radiation with which data is transmitted.

Electromagnetic radiation from the first satellite A to the second satellite B is sent occurs at the optical system 100 of the satellite B through the aperture BL and then through the first lens unit L1 and the second lens unit L2 , The electromagnetic radiation then enters the mirror system SP one and is from the first mirror surface (surface 6 ) on the second mirror surface (surface 7 ) reflected. From there, the electromagnetic radiation is directed towards the outer surface 8th reflects and then emerges from the mirror system SP through the outer surface 8th and passes through the third lens unit L3 and the fourth lens unit L4 to the filter element F , After passing through the filter element F the electromagnetic radiation strikes the detection unit e ,

Alternatively or in addition to this, the optical system 100 used for the acquisition of electromagnetic radiation.

From the 3 shows the aberration (astigmatic field curve and distortion). It has been found that the above-described embodiment of the optical system 100 has a distortion of ≤ 0.1%.

4 shows the diffraction modulation transfer function. The modulation is plotted against the spatial frequency for different wavelengths.

The optical system 100 is a catadiotropic system, which is very compact and has a low weight. Considerations have shown that the optical system 100 is particularly well suited for focusing electromagnetic radiation and in particular for communication between two locations. In addition, the use of the monolithic mirror system SP particularly advantageous because the production of such a mirror system SP is easily possible and also ensures that the overall length of the optical system 100 can be made small.

LIST OF REFERENCE NUMBERS

100

optical system

L1

first lens unit

L2

second lens unit

L3

third lens unit

L4

fourth lens unit

A

first satellite

B

second satellite

e

acquisition unit

F

filter

SP

mirror system

BL

cover

1

first surface of the first lens unit

2

second surface of the first lens unit

3

first surface of the second lens unit

4

second surface of the second lens unit

5

first outer surface of the mirror system

5a

first outer section

5b

second outer section

5c

first mirror section

6

first mirror surface of the mirror system

7

second mirror surface of the mirror system

8th

second outer surface of the mirror system

8a

second mirror section

8b

third mirror section

8c

third outer section

9

first surface of the third lens unit

10

second surface of the third lens unit

11

first surface of the fourth lens unit

12

second surface of the fourth lens unit

13

first surface of the filter element

14

second surface of the filter element

15

Entry area of registration unit

Claims (18)

Optical system (100) for focusing electromagnetic radiation onto a detection unit (E), the optical system (100) having a mirror system (SP), characterized in that - the optical system (100) has a first lens unit (L1) and at least one Detection unit (E) has - that from the first lens unit (L1) towards the detection unit (E) a second lens unit (L2), the mirror system (SP), a third lens unit (L3) and a fourth lens unit (L4) are arranged , and - that the mirror system (SP) is formed in one piece and has two outer surfaces (5, 8). Optical system (100) according to Claim 1 , characterized in that the first lens unit (L1), the second lens unit (L2), the third lens unit (L3) and / or the fourth lens unit (L4) each consist of a single lens. Optical system (100) according to Claim 1 or 2 , characterized in that the first lens unit (L1) has an entry surface (1) and an exit surface (2) for electromagnetic radiation, and that the entry surface (1) and / or the exit surface (2) of the first lens unit (L1) is spherical is / are. Optical system (100) according to one of the preceding claims, characterized in that the second lens unit (L2), the third lens unit (L3) and the fourth lens unit (L4) each have an entry surface (3, 9, 11) and an exit surface (4th , 10, 12) for electromagnetic radiation, and that both the entry surface (3, 9, 11) and the exit surface (4, 10, 12) of each of the second lens unit (L2), the third lens unit (L3) and the fourth lens unit (L4) are spherical. Optical system (100) according to one of the preceding claims, characterized in that a diaphragm unit (BL) is provided which, starting from the first lens unit (L1), is arranged in the opposite direction to the detection unit (E). Optical system (100) according to one of the preceding claims, characterized in that the optical system (100) is provided with an image angle in the range from -1.7 ° to 1.7 °. Optical system (100) according to one of the preceding claims, characterized in that the optical system (100) has a focal length in the range from 250 mm to 300 mm, and in that the distance between the first lens unit (L1) and the detection unit (E) is in the range from 40 mm to 70 mm. Optical system (100) according to one of the preceding claims, characterized in that the first lens unit (L1), the second lens unit (L2), the third lens unit (L3) and / or the fourth lens unit (L4) is formed from a radiation-resistant glass /are. Optical system (100) according to one of the preceding claims, characterized in that - a first outer surface (5) of the mirror system (SP) is directed towards the first lens unit (L1), with a second outer surface (8) of the mirror system (SP) towards the detection unit (E) is directed, and - that the mirror system (SP) has two mirror surfaces (6, 7), a first mirror surface (6) being assigned to the second outer surface (8) and a second mirror surface (7) being associated with the first outer surface ( 5) is assigned. Optical system (100) according to Claim 9 , characterized in that the first lens unit (L1), the second lens unit (L2), the third lens unit (L3), the fourth lens unit (L4) and the mirror system (SP) have the following properties, the properties being related to the optical system (100) with a focal length of f = 286 mm are standardized: area radius Distance [mm] Glass First surface (1) of the first lens unit (L1) 49.04640 4.87339 LAK9G15 Second surface (2) of the first lens unit (L1) 21.91030 5.96210 First surface (3) of the second lens unit (L2) 36.81300 3.18699 K5G20 Second surface (4) of the second lens unit (L2) 4302.0000 2.58957 First outer surface (5) of the mirror system (SP) infinitely 15.52 BK7G18 First mirror surface (6) of the mirror system (SP) -36.25680 -15.13957 mirror material Second mirror surface (7) of the mirror system (SP) -7.50000 15.13957 Second outer surface (8) of the mirror system (SP) -36.25680 2.01599 First surface (9) of the third lens unit (L3) -4.21700 2.31110 LAK9G15 Second surface (10) of the third lens unit (L3) 36.02700 2.55137 First surface (11) of the fourth lens unit (L4) -4.9400 4.60000 LF5G15 Second surface (12) of the fourth lens unit (L4) -6.38900 Optical system (100) according to one of the preceding claims, characterized in that the first lens unit (L1), the second lens unit (L2), the third lens unit (L3) and / or the fourth lens unit (L4) are each provided with an anti-reflective layer , so that a transmission of greater than or equal to 99.7% for electromagnetic radiation with a wavelength in the range from 550 nm to 580 nm and a transmission of greater than or equal to 90% for electromagnetic radiation with a wavelength of 1064 nm are achieved. Optical system (100) according to one of the preceding claims in connection with Claim 9 , characterized in that the outer surfaces (5, 8) of the mirror system (SP) are provided with an antireflection layer, so that a transmission substantially greater than or equal to 99.7% is achieved, and that the mirror surfaces (6, 7) of the Mirror system (SP) are provided with a silver layer, so that a reflection of substantially greater than or equal to 97% is achieved. Optical system (100) according to one of the preceding claims, characterized in that the optical system (100) is athermal. Optical system (100) according to Claim 6 , characterized in that the optical system (100) is provided with an image angle in the range of - 1.5 ° to 1.5 °. Optical system (100) according to Claim 7 , characterized in that the optical system (100) has a focal length in the range from 260 mm to 290 mm. Optical system (100) according to Claim 7 , characterized in that the distance between the first lens unit (L1) and the detection unit (E) is in the range from 50 mm to 60 mm. Data transmission system for the transmission of data between two locations (A, B) with at least one optical system (100) according to one of the preceding claims. System for the acquisition of electromagnetic radiation with at least one optical system (100) according to one of the preceding claims.

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