DE1199884B - Arrangement for deflecting the beam of an optical transmitter or amplifier - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

HOIs

German class: 2If- 90

Number: 1199 884

File number: J 27144 VIII c / 21 f

Filing date: December 17, 1964

Opening day: September 2, 1965

The invention relates to an arrangement for deflecting the beam of an optical transmitter or Amplifier.

The amplification of light by stimulated radiation is for communications applications, in optics, in program-controlled electronic computing systems, etc. have become more and more important since you now have a very high-energy beam of light available, which is also coherent. The usage such a very energetic light beam is particularly important where there is a visible one Display is used or where it is desired to quickly scan an area of space. This can be done in to some extent can be achieved by known methods, e.g. B. by the mechanical movement of Mirrors or prisms or by taking advantage of the electrically influenced birefringence in certain Crystals. All these known methods, however, are either outside of the optical transmitter or amplifier and are therefore independent of the type of light source or they correspond fails in some or all of the following three essential characteristics of a scanner Expectations:

Arrangement for deflecting the beam
an optical transmitter or amplifier

Applicant:

International Business Machines Corporation,

Armonk, N. Y. (V. St. A.)

Representative:

Dipl.-Ing. H. E. Böhmer, patent attorney,

Böblingen (Württ.), Sindelfinger Str. 49

Named as inventor:

Robert Vladimir Pole, Yorktown Heights, N.Y.

(V. St. A.)

Claimed priority:

V.St. v. America December 23, 1963 (332617)

High scanning speed, high resolution and rapid angular deflection.

For example, mechanical scanners are inherently slow. Procedures with the electrical Work influencing the birefringence, lack the resolving power and the fast Angular deflection.

The arrangement according to the invention for deflecting the beam of an optical transmitter or amplifier avoids the disadvantages mentioned by the fact that the symmetry properties of the spherical mirror are limited optical resonator are initially designed so spherically symmetrical that no oscillation axis is distinguished from another, and only are disturbed by the action of electric or magnetic fields in such a way that there is only one axis at a time through the system, along which the system has a maximum quality and along which the output beam is spreads.

According to a further feature of the invention, there is a constant movement of the axis of maximum quality and thus the output beam of the optical transmitter or amplifier duich changes over time the symmetry properties of interfering electrical or magnetic fields are achieved.

In the case of the arrangement according to the invention, the emission direction at the same time makes the direction more optimal Light amplification. A new type of optical resonator was required for this type of beam control be created. The novel optical resonator of the optical transmitter or amplifier, hereinafter referred to as a conjugate-concentric resonator, causes the high resolution and the rapid angular deflection of the beam.

This conjugate-concentric resonator consists of a spherical, selectively fluorescent solid-state medium, which is located midway between a pair of concentric outer spherical mirrors. The distance between the selectively fluorescent medium and the mirrors is chosen so that the both mirrors are mutually optically conjugated,

d. that is, they are in relation to the spherical, selectively fluorescent medium acting as a lens in the object or thing surface and in the picture surface at the same time. In other words, the optical one Resonator not only formed by the outer mirror, but in contrast to the prior art by the combination of these mirrors with the lens effect of the selectively fluorescent solid-state medium. Since such a geometric arrangement has complete spherical symmetry (up to the edges of the Mirror), the system is completely indifferent to the angular position within these limits. This means that there is no preferred

509 659/195

3 4

axis within these limits. Go to F i g. 4 is a vector diagram showing the instantaneous deflection of the beam from the optical transmitter is the values of two Cartesian components of the from the optical symmetry of the system from outside in the resonator of the optical transmitter or amplifier supplied and controlled electrical or magnetic attached selectively fluorescent medium from fields disturbed. These outer fields cause the 5 going light vector shows

Disturbance of symmetry by changing the polar F i g. 5 shows an example of a scanning system in which

state of the light beam, the intermediate of the scanning beam through the output beam of a

Space is formed between the selectively fluorescent medium of the optical transmitter or amplifier

and goes through the outer mirrors. The outer ones and that according to the magneto-optical Kerr effect

Fields are sized and the materials in which io works

Gap chosen so that the disturbance that F i p. 6 is a graphical representation of the effects of magnetism in refraction and polarization, such as seeing field strength as a function of the angular coordinate, that at any given point in time and for each which serves to determine the operation of the system according to a given external voltage or any given figure. 5 to make understandable,
external current there is only a single axis through the 15 F i g. 7 is a vector diagram giving the rotation of the system along which the system has minimum light vector E ₀ at various points along the losses or a maximum Q Q. The following axis of the system shows, and
of this, the optical transmitter or amplifier tends to be F i g. 8 is a graphical representation of the reflection cause of the non-linearity of its own vibration properties along the surface of a mirror of the shaft to vibrate only in the direction of the maximum 20 resonators of the optical transmitter or amplifier Q-Q . In other words, only as a function of the angle coordinate α.
In Fig. 1 only the conjugate-concentric number of possible vibration types, whose optical resonator is shown, which is either spherical width direction with the axis of the maximum symmetrical or cylindrical. The quality Q coincides is maintained, all 25 selectively fluorescent medium 2 either does not consist of others. Since the angular position of the axis of maximum gallium arsenide or of a ruby, the normal quality Q, is a function of the external fields, the time changes in these fields with chromium, neodymium or any other result in a steady solid material doped with, and shows you through a scanning movement a vibration type. Stimulation achievable reinforcement effect if there is

The speed at which the scanning is excited with the excitation energy L. Such a

can be performed is either through the Ge selectively fluorescent medium with a refractive

speed at which the external fields change index η is spherical. The mirror m _x

can be, or through the natural deceleration and m ₂ with the radii of curvature R are concen-

aging time of the selected selectively fluorescent Me- Irish. Which surrounds the selectively fluorescent medium 2

diums limited. Both boundaries are of the type 35 and located between the mirrors m _x and m ₂

that a scanning speed that 1 MHz over- lent substance 4 can be made of any material, too

strides, is easily achieved. consist of air as long as its refractive index n ₀

The triggering of the system, i.e. the smallness of one is smaller than the refractive index η and the substance point on one of the mirror of the cavity of a sufficiently high permeability for the light generated by the optical transmitter or amplifier is only numerical by 40 optical transmitters or amplifiers The aperture of the system is determined. In has. The radius R of the optical resonator in practice becomes the numerical aperture through which, according to the known Gaussian lens formula, the spherical aberration of the optical resonator according to the invention of the optical transmitter or V - ^ i (i)

more diminished. Various possible modifications 45 nn ₀ - n _o ^z

lungs of the resonator of the optical transmitter or

Amplifier, through which the spherical aberration is selected, in which η is greater than H ₀ . In short it is

wrestling will be discussed later. R chosen so that as a result of the lens effect of the

Further details of the invention result from the ruby 2, the two mirrors m _x and m _2, which are the opposite of the more detailed description of a preferred standing and image surface of the ruby 2. Thus, the embodiment of the invention in connection with the ruby 2 fulfills two main functions, namely with the drawings; in these shows it serves as a stimulable medium of reinforcement

F i g. 1 schematically shows a ray diagram of and at the same time as a lens. The material chosen for the selectively fluores-conjugate-concentric optical resonator-specific medium 2 should meet the requirements of the invention, 55 excitation energy L easily converted into stumbled radiation.

F i g. 2 another embodiment of the convert in and should also be used as a lens according to the above

F i g. 1 shown conjugate-concentric op- given formula (1) serve,

table resonator, from the geometry of F i g. 1 is obvious

F i g. Fig. 3 shows an example of a scanning system in which this type of optical resonator is completely

the scanning beam through the output beam of a 60 is spherically symmetric (within the edges of the

optical transmitter or amplifier is formed and mirrors Jn ₁ and m ₂ ). Hence the optical resonator

in which the electro-optical Kerr effect is used. within these limits also completely indifferent

In the right part of FIG. 3 is a scan in the ferent. In addition, it is clear to the professionals

X-Z plane shown, and in its left part that one of the transversal fundamental modes

The arrangement shown, which is in the right part 5g of this optical resonator, d. H. the distribution of the

and only by 90 ° around the electromagnetic field shown in FIG. 1 shown

Z-axis has been rotated, is used for scanning in the form possessed by the course of the outer

7-Z-plane, rays PP ₁ P ₁ 'p' and PP ₂ P ₂ 'P' according to the geometrical

5 6

Irish optics is approximated. The basic on the mirror Tn ₁ or m ₂ . For the obtained property of such a vibration type, that solution is a magnification ratio of 1: 1, it converges on the surfaces of the mirrors Tn ₁ and m _2. provided.

In other words, the maximum energy concentration because the volume of the selectively fluorescent metration occurs at the points on the sphere, the ₅ diums 2, which are due to spherical aberrations on the surfaces of the mirrors. not involved in the reinforcement, useless with

Due to the high indifference of the optical excitation energy is applied, it is desirable resonator may comprise one or many such base that acts as a lens selectively fluorescent medium maintained for 2 types of vibration at the same time, the _S o to be formed, that the unused volume of minimal oscillations along any Direction PP 'is within ₁₀ . In Fig. 2 is a possible modification of the half of the shape of the stimulable medium 2 represented by the outer diameter of the mirror Tn _{1 , made by and / H 2} . Unless the deliberate disturbance or operation of the spherical but external effects is diminished. From Fig. 2 it can be seen that for the selection of a vibration type made at A and A ' parts of the originally spherical, depend both the number of these convergent ₁₅ selectively fluorescent medium were removed, so vibration types and their direction only depends on the fact that the selective fluorescent medium 2 einden no losses due to the inhomogeneity of the emerging excitation light, the misalignment of the mirrors and that of the selectively fluorescent medium, the imperfections on them as well as from the disturbances do not serve any useful purpose. To reduce off due to inhomogeneity in the distribution and ₂₀ of the harmful effect of the spherical aberration in the size of the excitation energy L. Many other actions can be taken

According to the invention there will be deliberate interference, but they are for those in FIG. 1 shown

caused in the optical resonator to an invention incidental. There are such measures

those types of vibrations that took to a given one took hold of the nature of being selective

Swing point in time in a desired direction, ₃₅ fluorescent medium 2 material used compatible

are to be selected. However, it doesn't require the many

The width P ₁ 'P ₂ ' of the distribution of the vibration combinations of the spherical, selectively fluorestypes on the surface of the acting as a lens zenten media for an optical transmitter or Verselektiv fluorescent medium 2 determines the size stronger and the measures to correct the light spot the mirrors Tn ₁ , m _z . More precisely ₃₀ spherical aberrations that can be used, said this size is to be used with the resolution to expose. Related to the reflection losses at the boundary of the system, a function area between the one acting as a lens is selective

its numerical aperture NA = - ^ j ^ -r, wherein fluorescent medium 2 and the one surrounding it

_ _ 2 (R - r> Medium 4 to decrease, the areas S and 5

D ₀ = P ₁ ' P ₂ '. The calculations of the vibration _{35 m} j _{t be} provided with an anti-reflective coating,

types show that the diameter D of such a Das in FIG. 1 shown selectively fluorescent

The light spot on the mirrors is as follows: Medium 2 has the shape of a sphere with radius r

can be expressed: (or the shape of a cylinder with radius r,

1.22 · λ if only one scanner for a two-dimensional

D m 1.6 · Da = 1.6 · - ^> 40 sampling is desired) with a refractive index n. The spherical mirrors Tn ₁ and m _z have

where λ is the wavelength of the output radiation of the same radius R, and the refractive index of the optical transmitter or amplifier, and 1.6 is a numerical factor surrounding the selectively fluorescent medium 2, which is n ₀ from the above calculations. The materials and dimensions results, and Da is the diameter of the Airy disk 45, « _o j -n · t. π no ..., ". chens for this numerical aperture. S ^{are eraaß of Bez "ehun} S ^R =" ^ r ^ & ™™ -> In F i g. 1, the angle β is the angle between where η is greater than n ₀ . The radii of curvature ^ _{1 of} a main axis PP ' and the outermost ray and R _{2 of} the mirrors Tn ₁ and m ₂ need not be equal to P ₁ ' P '. If the selective fluorescent medium is 2, but such differences do not consist of a ruby, the refractive index 50 has an influence on the behavior of the system as long as the η - 1.76 and the refractive index n ₀ for nitrobenzene are optically conjugated to both mirror surfaces . Less than 1.553. The numerical aperture of the different radii of curvature as a lens only result in an effective, selectively fluorescent medium 2 with different optical magnifications.

sin / S or for relatively small angle aniS ^^. ^We ™ ^R i ~ ** = f | ^ema f <* «relationship (1)

^r R 55 was chosen, the spherical one becomes selective

Can -f the ratio using the equation (1) ^flu0 ™ ^te medium 2 as a lens with a comparison

R ^{6 v} ' enlargement of 1: 1, so that a point P is maximal

are expressed as n ₀ - * - , which has the value 0.17 ^E , ^ne ^ ^{ie d} "output beam of the optical transmitter

^u η is regarded as the object point and the other

accepts. The corresponding diameter D _{0 of} the 60 point P 'of maximum energy of the image point of the Auslassischen Airy disk is D = ^{1> 2 2} * °' ⁷ - = 5u.m transmission beam. Any other point β on that

⁰ 0.17 r · · surface of the mirror Tn ₁ is used as a lens

The actual size of the light spot of the excited acting selectively fluorescent medium 2 as point Q '

Vibration type is 60% larger, ie D = 8 μΐη. imaged on the surface of the mirror m _%. Through the

The resolution of the system according to the invention via the lens effect of the selectively fluorescent medium 2

meets the resolution of the best known devices for each of the two mirrors Tn ₁ and m _{2 represents} the image area

Light spot scanning by an order of magnitude and is the other. The optical resonator of the optical

also regardless of the angular position of the light spot transmitter or amplifier according to FIG. 1 receives all

7 8

Vibration types equally well upright. Such a Schwin field are exposed. The two components are:

types of movement have the form of the rays, first of all, those that are parallel to the electric field

PP ₁ P ₁ 'P' and PP ₂ P ₂ 'P' enclosed Vo- runs, and second, those that run perpendicular to the

lumens. external electric field runs.

Now let the F i g. 3 the means for 5 It is assumed that a polarizer 28

Abolition of the above-mentioned angular in-between the selective fluorescent acting as a lens

Difference between the optical resonator and the medium surrounding it 4

the optical symmetry of the conjugate-concen-is inserted. When using crystals,

Irish optical resonator by means of an externally such as ruby, which acts as a selectively fluorescent medium

applied and controlled electrical field be ίο the crystal itself as a polarizer 28 due to the

wrote. The basic characteristics of the polarized nature of its fluorescence. If that

F i g. 3 are the method which previously proceeded from the selectively fluorescent medium 2

mentioned disturbance as well as the scanning movement of the light is linearly polarized in a direction which in

Axis of maximum quality Q to achieve. This is located by a plane that coincides with the X and Y axes

the interaction of a time-variable, 15 angle of 45 ° includes (see Fig. 4), and that

spatially invariant phase delay of a grain outer field / is oriented as shown in FIG. 4th

component of the electric field is shown in a part of the, meet the two components e _x

optical resonator and the spatially variable and e _y after passing through the nitrobenzene 4

borrowed, but time-invariant phase delay on the inner surfaces of the compensator 24 with

the same component of the field in another 20 a relative phase delay δχ a. In which

Part of the optical resonator causes. When going through the compensator 24,26 suffer

F i g. 3 arrangement, the selective components e _x and e _{y can have} a different relative phase

fhiorescent medium 2 a ruby and the material 4 delay öc. The first phase delay is δ κ

between the mirrors W ₁ and m _{2 be} nitrobenzene. depending on the applied electric field /,

Nitrobenzene was chosen because it is a 25 that changes over time, but is independent of the

has a high Kerr constant. Other materials, angle coordinate <x. Therefore: δ κ = δ κ [/ (O] - The

which have a high Kerr constant, the second phase delay δα is independent of time.

can also be selected as long as the previously pending, but dependent on the angular coordinate cc,

given relationship (1) is fulfilled. The electrodes 20 so that the following applies: δα = dc (οι). After the reflection on

and 22 are experienced with a suitable 3 ° mirror m ₂ , not shown, the two components e _x and

Voltage source connected to an electrical e _{y of} the light vector the same delays öc

Field /, which runs parallel to the plane of the drawing, to and δκ, before being passed through the polarizer 28 into the

place. The optical axis 23 of the nitrobenzene selectively fluorescent medium 2 return. at

runs parallel to the electric field /. An optical of their return through the polarizer 28 can

Compensator, which in principle acts in the same way as a 35 the two components e _x and e _{y as} follows

Babinet compensator, is made of glass or can be expressed as:
suitable pre-stretched KunststofF24 and a thin,

pointed glass or plastic section 26 e _x - E _x q ~ '° ",
made of the same material as part 24, but not

pre-stretched, manufactured. The optical axis 25 of the 40 _e - β _s ~ '[ ^a "~ ² ( ^a K ~ ^d c)] _ ^)
tapered section 24 is perpendicular

optical Kerr effect creates a relative phase components e _x and e _y happen. Hence the

delay between the two components of the 45 combined instantaneous value of the field e that corresponds to the

Light vector when it reaches certain materials such as selectively fluorescent medium 2, through the

Go through nitrobenzene, which gives a strong electrical the following relationship:

e = ψ (e _x + e _v ) = ψ <Γ '"[e _x + E _y ^ ² C *"' *)]. (3)

The resulting light intensity arriving at the selectively fluorescent medium 2 can be as follows can be expressed:

I = < _e . e * y = - [<£ ^> + <£ ^> + 2 } ß ^ Ey cos ² (δ _κ - δ O)] , (4)

Yes

where the asterisk is the conjugate complex quantity instead of equation (4):

and the brackets <> the temporal 1

Averaging calculation. When neglecting the ab- 60 / = ~ j ^T o P- + cos 2 (ö _K - öc)] = T ₀ cos ² (δ _κ - ö _c ).

sorption of the two components e _x and e _y receives ,,,.

one has the following relation: * ■ '

The effective reflectivity as a function of

(E _x Zy - (E _y ² y - -, (5) time and the angular position can now be given by the following

2 '65 relationship can be expressed:

where I _{0 is} the input intensity of the at the Polari Reffif, a) = - ~ = cos ² [δκ (ή - <5c (a)]. (7)

Sator 28 represents incoming light. Then *

In other words, by means of the phase delay achieved by the Kerr effect (using an externally applied electric field f) and the phase shift achieved by the Babinet compensator, which is dependent on the angle coordinate, an intensity of the in the selectively fluorescent medium is obtained 2 returning light, which depends on both time and angle.

Since the Q of the optical resonator is proportional to the effective reflectivity R _e ff, it can be seen that the position of the axis of the maximum Q depends on the applied voltage (which is variable with time) and the shape of the cos ^a function in equation (7) serves to suppress all types of vibration except those whose axes coincide closely with the axis of maximum quality Q. As can be seen from FIG. 8, the maximum angular field 2 « _{0 should be} such that the occurrence of two maxima of the reflection function Reff within its range is prevented. The period ρ should be greater than 2 « ₀ , otherwise a twofold indifference occurs in the system.

The setting of the axis of the maximum quality Q in the FZ plane, ie the scanning in the FZ plane, can be carried out in the same way by the steps shown in the left part of FIG. 3 is provided with the same physical facilities, but rotated by 90 ° about the Z-axis, which is shown in the right part of FIG. 3 are shown.

F i g. Figure 5 shows another way of performing a scan. The device used differs from that in FIG. 3 by using the magneto-optic Faraday effect in place of the electro-optic Kerr effect to obtain the same results as previously described. Since the two halves of FIG. 5 are identical, apart from the 90 ° rotation about the Z axis of all the components in the left half of the figure, the description of the mode of operation of the right half of the system according to FIG. 5 is sufficient for explaining the invention. In the optical resonator between the selectively fluorescent medium 2 and the mirror m ₂ there are two components which are referred to below as Faraday rotators. The central rotator is R ₁ R. A polarizer Pr is located between the selectively fluorescent medium 2 and the rotator R ₁ R when the selectively fluorescent medium 2 shows no polarized fluorescence. The central rotator R ₁ R is located in a magnetic coil C, which generates a radial magnetic field H ₁ R. The other Faraday rotator is labeled R ₂ R and is in its own static magnetic field H ₂ R, the field distribution of which is shown in FIGS. 5 and 6 is shown. Such a magnetic field can be generated by permanent magnets 50 and 52.

The magnetic field H ₂ R is stationary, but its intensity is an odd monotonous function of the angular coordinate <x (see FIG. 6). The magnetic field H ₁ R of the central rotator .R ₁ H is not a function of the angle <x, but is variable over time. At time t ₀ , when the vibrations of the optical transmitter or amplifier begin, the polarization of the wave leaving the selectively fluorescent medium 2 is determined by the polarizer Pr . The transmission axis of the polarizer Pr lies in the plane X = O. When the polarized light passes through the first rotator R ₁ R , the light undergoes a rotation <9 ₁₊ = K ₁ H ₁ R (t), in which K _{1 is} a constant that depends on the value of Verdet's constant of the medium 4 and on the geometry of the rotator R ₁ R depends. The rotation Θ ₁₊ is shown in FIG. 7 is shown as going from point 0 to point 1.

When passing through the second rotator R ₂ R , the light experiences an additional rotation Θ ₂₊ , which is shown in FIG. 7 runs from point 1 to point 2 and which is equal to K ₂ H ₂ («) where K ₂ is Verdet's constant for the second rotator and H ₂ r (k) is the magnetic field of the second rotator R ₂ R at a point of Mirror m% , which corresponds to the angle «. After the reflection on the mirror m ₂ , the light is rotated again by the amount (9 ₂ - (from point 2 to point 3 in FIG. 7) and by B ₁ (from point 3 to point 4 in FIG. 7) The two rotations are the same size as the rotations 6> ₂₊ and <9 ₁₊ . The Faraday rotation is additive regardless of the direction of propagation of light from the selectively fluorescent medium 2. Therefore, the total rotation is <9 ( from point 0 to point 4 of Fig. 7) of the beam of the optical transmitter or amplifier returning to the polarizer Pr.

From the vector diagram of FIG. 7 it can be seen that the component E _{y of} the rotated light vector E _{0 is} equal to E ₀ '· cos Θ, which in turn is equal to E ₀ · cos Θ if the absorption by the rotators R ₁ R and R ₂ R is negligible. The effective reflectivity Reff is then

Reff (t, Oi) = = cos ² Θ = cos ² 2 [K ₁ H ₁ R (t) - K ₂ H _{% R} («)].

The last term is identical in form to the term for the effective reflectivity obtained in the electrical variant of this method. All implications of the effective reflectance thus obtained for the magneto-optic method for canceling the angular degeneracy of the mirror m ₂ are the same as for that in connection with FIG. 3 electrical procedures described.

summary

The invention described shows that a scanning device operating with an optical transmitter or amplifier can be made to have the following very desirable properties:

1. High scanning speed resulting from scanning by electrical means within the optical resonator of the optical transmitter or amplifier is controlled,

2. High resolution of the scanning light spot, which is a result of the generation of the light of the optical transmitter or amplifier in a certain direction in an angular manner Indifferent optical resonator is, in place of the deflection of light, which by a light source is generated outside the scanning device,

509 659/196

Claims (1)

3. a strong radial field, which is also due to the high degree of indifference of the inventive optical resonator of the optical transmitter or amplifier is obtained; 4. due to the fact that the device works with an optical transmitter or amplifier the output energy is considerably higher than that obtained with conventional scanning devices, e.g. B. cathode ray tubes, is available. The above properties allow the use of the optical transmitter or amplifier according to the invention as an optical radar device, as a means for reading out optically stored information, as an electrically controlled machining tool in which the heating properties of the Output beam of the optical transmitter or amplifier can be used, and more generally as Display device. The person skilled in the art will easily find further possible uses. 20th Patent claims: 1. An arrangement for deflecting the beam of an optical transmitter or amplifier, characterized in that the symmetry properties of the _{optical resonator limited by spherical mirrors (/ M 1} , m ₂ ) are initially formed spherically symmetrically that no oscillation axis is distinguished from another, and only by the action of electric or magnetic fields, are disturbed in such a way that there is only one axis through the system, along which the system has a maximum quality and along which the output beam propagates. 2. Arrangement according to claim 1, characterized in that a continuous movement of the axis maximum quality and thus the output beam of the optical transmitter or amplifier Changes over time in the electrical or magnetic properties that interfere with the symmetry properties Fields is reached. 3. Arrangement according to claims 1 and 2, characterized in that the optical resonator of the optical transmitter or amplifier by the interaction of a spherical fluorescent medium (2) with two concentric, on opposite sides of the medium (2) arranged spherical shell-shaped concave mirrors Qn ₁ , W ₂ ), each of which represents the image surface of the other as a result of the lens effect of the central medium (2), and that means (20, 22, 24, 26 in FIG. 3; R _lR , R ₂ R in FIG ) are provided to disturb the symmetry properties of the optical resonator. 4. Arrangement according to claim 3, characterized in that as a means for disrupting the Symmetry properties of the optical resonator in the space between mirror and medium firstly a Kerr cell (20, 22, in Fig. 3) is provided is generated by an applied, time-varying electric field of one beam component granted a time-variable phase delay, secondly an optical compensator (24, 26), that of the same ray component depends only on the angular coordinate Phase delay granted, and thirdly, if necessary, polarizers (28) selectively surrounded by fluorescent medium. 5. An arrangement according to claim 3, characterized in that as a means of disturbing the symmetry properties of the optical resonator between the polarizers (Pr) and each of the reflectors Qn _1, M ₂₎ ^zwe of the optical transmitter rotating Faraday rotators i the plane of polarization of the beam ( R ₁ R, R ₂ R in Fig. 5), of which the first generates a time-varying magnetic field and the second generates a stationary magnetic field, the intensity of which is a function of the angular coordinate. Considered publications:
French Patent No. 1,340,840. 1 sheet of drawings 509 659/196 8.65 © Bundesdruckerei Berlin