DE102020208336A1 - Spin-based gyroscope and method of operating the spin-based gyroscope - Google Patents

Abstract

The invention relates to a spin-based gyroscope, comprising a vapor cell arrangement (201), the vapor cell arrangement (201) having a first pumping area (2011) and a second pumping area (2012), wherein in the first pumping area (2011) a precession movement occurring in the first pumping area ( 2011) located polarizable electron spins with a first direction of rotation can be generated, wherein in the second pumping area a precession movement of the polarizable electron spins located in the second pumping area (2012) can be generated with a second direction of rotation and wherein the first direction of rotation and the second direction of rotation are opposite to each other.Furthermore the invention relates to a method for operating the spin-based gyroscope.

Description

State of the art

In CN109737945 A describes a SERF gyroscope and an electronic evaluation method of the measurement signal of the SERF gyroscope for an improved signal-to-noise ratio.

Core and advantages of the invention

In the field of navigation, ever more precise sensors, in particular gyroscopes, which can precisely measure the rate of rotation, are required. High-precision rotation rate sensors based on optical resonators are already installed in aircraft today. For autonomous driving and flying, as well as for applications that have poor connections to GPS, radar and similar systems, such as underwater navigation, high-precision on-board sensors are required, which places special requirements on the size and the required construction volume of the high-precision on-board sensors. Ensuring safe stopping, based on inertial sensors, in the event of the failure of the other systems is essential, especially for use in the field of autonomous driving. In order to improve the safety and comfort of autonomous vehicles, in particular, a significant increase in drift stability and a significant reduction in the noise of rotation rate sensors (= gyroscope) is desirable in order to enable purely inertial navigation even for longer distances, e.g. in tunnels or in urban canyons . Therefore, the focus for these applications is on gyroscopes known from basic research, the nuclear magnetic resonance signals of atomic nuclei with non-vanishing magnetic moment (spin 1/2 nuclei, spin 3/2 nuclei, generally nuclei whose spin value is an odd multiple of 1 / 2 is). These show increased drift stability and increased accuracy compared to current MEMS rotation rate sensors used in the automotive industry. Furthermore, they show reduced disturbance from vibrations and accelerations.

wobei B₀ ein statisches magnetisches Feld (Vormagnetisierungsfeld) ist, welchem die Dampfzelle ausgesetzt ist und γ das gyromagnetische Verhältnis bezeichnet. Das bedeutet, dass je höher das gyromagnetische Verhältnis γ eines Stoffes ist, desto sensitiver ist dieser bezüglich Magnetfeldschwankungen. Um daraus resultierende Störungen zu minimieren, werden bei spinbasierten Gyroskopen im Stand der Technik Kernspins von Edelgasen zur Rotationsmessung verwendet. Solche spinbasierte Gyroskope, welche mittels einer Änderung der Präzessionsbewegung von Kernspins eine Rotation des Gyroskops detektieren, werden als Kernspinresonanz-Gyroskope oder auch NMR-Gyroskope (NMR=nuclear magnetic resonance) bezeichnet.Spin-based gyroscopes are based on steam cells, whereby the resulting spin-Larmor precession ω _{larmor of} the spins is read out in a steam cell. An outer rotation ω _rot represents an additional rotation, which can be determined by reading out the rotation frequency ω _{mess as follows:} $${\mathrm{\omega }}_{\text{mess}}={\mathrm{\omega }}_{\text{larmor}}\pm {\mathrm{\omega }}_{\text{Red}}=\mathrm{\gamma }{\text{B.}}_0\pm {\mathrm{\omega }}_{\text{Red}}$$

where B _{0 is} a static magnetic field (bias field) to which the vapor cell is exposed and γ denotes the gyromagnetic ratio. This means that the higher the gyromagnetic ratio γ of a substance, the more sensitive it is to magnetic field fluctuations. In order to minimize the resulting disturbances, in spin-based gyroscopes in the prior art nuclear spins of noble gases are used to measure rotation. Such spin-based gyroscopes, which detect a rotation of the gyroscope by means of a change in the precession movement of nuclear spins, are referred to as nuclear magnetic resonance gyroscopes or also NMR gyroscopes (NMR = nuclear magnetic resonance).

An exemplary structure of an NMR gyroscope and its mode of operation are, for example, in "MEMS Components for NMR Atomic Sensors" (RM Noor and AM Shkel; Journal of Microelectromechanical Systems, 27 (6): 1148-1159, Dec. 2018) set out.

Interference, such as electrical noise from components of the spin-based gyroscope, fluctuations in lasers used in the spin-based gyroscope (especially frequency, detuning and power of the laser), and noise from the magnetic fields used in the spin-based gyroscope, etc., as well as interference magnetic fields or temperature gradients have a major influence the drift accuracy over time and the sensitivity of the gyroscope.

The invention relates to a spin-based gyroscope and a method for operating the spin-based gyroscope.

An advantage of the invention with the features of the independent claims is that the effects of external interference on the measurement result of the spin-based gyroscope can be reduced in a simple manner without complex and costly modifications in order to increase the sensitivity and reliability of the spin-based gyroscope and to reduce signal drift. In particular, the invention enables a miniaturized spin-based gyroscope to be implemented with high sensitivity and reduced drift; Parameters are conditioned, such as a magnetic field environment and / or an ambient temperature of the spin-based gyroscope, as well as internal interference signals. Due to this interference correction and due to the fact that it occurs optically (in contrast to a purely electronic correction), the precession movement can occur when using vapor cells which contain alkali metals such as rubidium, cesium, potassium, etc. as the measuring medium (first medium) the electron spins of the alkali metal vapor can be read out directly in order to determine a rate of rotation of a rotation of the spin-based gyroscope.

• • eine Dampfzellenanordnung, umfassend ein erstes Medium, welches in der Dampfzellenanordnung angeordnet ist,
• • eine Beleuchtungsanordnung zum Beleuchten des ersten Mediums in der Dampfzellenanordnung, wobei die Beleuchtungsanordnung dazu eingerichtet ist, durch optisches Pumpen Elektronenspins des ersten Mediums zu polarisieren,
• • eine Magnetfelderzeugungseinrichtung zur Bereitstellung eines Vormagnetisierungsfelds und eines oszillierenden Magnetfeldes am Ort der Dampfzellenanordnung, wobei das Vormagnetisierungsfeld zur Festlegung einer Richtung einer Präzessionsbewegung der polarisierbaren Elektronenspins des ersten Mediums und das oszillierende Magnetfeld zur Synchronisation der

This is accomplished with a spin-based gyroscope, comprehensively

• • a steam cell arrangement, comprising a first medium which is arranged in the steam cell arrangement,
• A lighting arrangement for illuminating the first medium in the vapor cell arrangement, the lighting arrangement being set up to polarize electron spins of the first medium by optical pumping,
• • a magnetic field generating device for providing a bias magnetic field and an oscillating magnetic field at the location of the vapor cell arrangement, the bias field for defining a direction of a precession movement of the polarizable electron spins of the first medium and the oscillating magnetic field for synchronizing the

• • eine Detektionsanordnung, welche zur Detektion einer Drehung des spinbasierten Gyroskops eingerichtet ist.

Precession movements of the polarizable electron spins of the first medium are established and

• A detection arrangement which is set up to detect a rotation of the spin-based gyroscope.

The vapor cell arrangement has a first pumping area and a second pumping area, wherein in the first pumping area a precession movement of the polarizable electron spins located in the first pumping area can be generated with a first direction of rotation and wherein in the second pumping area a precession movement of the polarizable electron spins located in the second pumping area can be generated with a second Circulation sense can be generated. Here, the first direction of rotation and the second direction of rotation are opposite to one another. I. E. the precession movement in the first pump area and the precession movement in the second pump area are opposite to each other: if the electron spins in the first pump area precede clockwise, for example, the electron spins in the second pump area simultaneously precess counterclockwise. The detection arrangement is set up to detect a rotation of the spin-based gyroscope about a direction of the bias field from a change in the precession movement of the polarizable electron spins.

In particular, it is not necessary for the vapor cell arrangement to include a noble gas for generating polarized nuclear spins in order to transfer the polarization of the electron spins generated by optical pumping from the optically pumped electron spins to the nuclear spins of the noble gas by means of a strong electron-nuclear spin interaction. I. E. In particular, the steam cell arrangement does not include any noble gas for detecting a rotation of the spin-based gyroscope from a change in the precession movement of the polarizable nuclear spins. In the spin-based gyroscope according to claim 1, the rotation of the spin-based gyroscope is detected directly from a change in the precession movement of the polarized electron spins, which is caused by the external rotation of the spin-based gyroscope.

In contrast to this, prior art NMR gyroscopes make use of the fact that the electron spins of the alkali metal vapor react sensitively to the periodic magnetic field change caused by the in-phase nuclear spin precession of the nuclear spin of the noble gas, in order to thus detect a change in the nuclear spin precession by detecting the electron spin precession to detect the change in the nuclear spin precession indirectly by measuring the electron spin precession and to determine the rate of rotation of the gyroscope from this.

Advantages of using steam cells filled with alkali metal vapor and in particular without noble gas are: a saving in the costs of noble gases, simplified production and filling of the at least one steam cell of the steam cell arrangement, a simplified sensor arrangement, a simplified sensor design and a simplified sensor structure combined with lower production costs. In particular, the spin-based gyroscope comes with fewer magnetic field coils and without sacrificing performance their current drivers and control loops as spin-based gyroscopes, such as NMR gyroscopes, from the prior art.

Another advantage is that the present invention enables fast and highly accurate signal processing through operation at high frequencies. By working with purely high-frequency signals, signal processing is simplified and, despite many filters, fast signal processing with a high bandwidth is enabled.

It is further advantageous that the spin-based gyroscope according to claim 1 has a fast start-up time (= time after switching on until the spin-based gyroscope is ready for use), since optical pumping and spin alignment of alkali metal gases can be controlled very efficiently via the laser intensity and the In comparison, the slower spin polarization of the noble gas via the alkali metal atoms is omitted in prior art NMR gyroscopes.

One advantage that results from the use of two pump areas with oppositely precessing electron spins is an intrinsic cancellation of internal noise signals, in particular electronic noise signals from lasers, magnetic fields, etc., charge shifts in the shielding, etc., and the resulting higher sensitivity and lower drift of the spin-based gyroscope. Interfering influences, such as noise (common noise), which act on both pump areas, can thus cancel each other out during the measurement and consequently a higher accuracy of the rotation rate of a rotation of the spin-based gyroscope determined with the spin-based gyroscope can be achieved. This also enables the gyroscope not to require any noble gases to carry out the measurement.

The steam cell arrangement may include one steam cell, two steam cells, or more than two steam cells. A steam cell is designed, for example, as a hollow body made of glass, the interior being hermetically sealed against the surroundings of the steam cell, so that in particular gases from the interior of the steam cell cannot escape during operation and pressures can be generated within the steam cell which differ from the ambient pressure of the spin-based gyroscope . To set a pressure and / or to generate a gas in the steam cell, for example, a heating element can be arranged on the steam cell or in the vicinity of the steam cell. For example, electrically conductive wires can be used as the heating element, the temperature of the media in the steam cell being adjustable via the electrical current flowing through the wires. Another embodiment for heating the steam cell comprises a laser; H. a heating laser, the laser light of which is directed onto an area of the steam cell. The laser light is absorbed by the material of the steam cell, in particular the silicon, and thus heats the steam cell. In particular, the at least one steam cell can be made of glass and, for example, round, cylindrical or cube-shaped.

The lighting arrangement comprises an illumination source, such as, for example, a laser or a laser diode, in particular a surface emitter (VCSEL) for illuminating. An irradiation direction of the light used for illumination has at least one component parallel or antiparallel to the magnetic field direction of the bias field, in particular the irradiation direction is parallel or antiparallel to the magnetic field direction of the bias field (M _z mode). Alternatively, the direction of irradiation can have a component orthogonal to the magnetic field direction of the bias field, in particular the direction of irradiation can be orthogonal to the magnetic field direction of the bias field (M _x mode). The wavelength of the light emitted by the illumination source is matched to the energy scheme of the first medium, so that the light can be absorbed by the first medium and a polarization of the electron spins can be generated (optical pumping). Circularly polarized light is preferably used for the illumination. The lighting arrangement can comprise optical elements for beam guidance and / or beam shaping (for example mirrors, lenses, etc.) and for setting the polarization of the light (for example polarizers).

In the case of circularly polarized light, a distinction is made between σ ⁺ polarization ("Sigma-Plus") and σ ^- polarization ("Sigma-Minus"), which causes a change in the magnetic quantum number m of +1 or -1 at atomic transitions between energy levels . Linearly polarized light (Δ m = 0 at the atomic transition) is called π-polarized light. The following applies here: A right circularly polarized light beam against the static bias field, ie antiparallel to the bias field, is equal to a left circularly polarized light beam along the bias field, ie parallel to the bias field.

The first medium can in particular be gaseous or can be converted into a gaseous state by heating the steam cell. For example, an alkali metal such as rubidium (Rb), in particular rubidium 87 ( ⁸⁷ Rb) or rubidium 85 ( ⁸⁵ Rb), cesium (Cs), potassium (K), etc. or mercury (Hg) can be used as the first medium.

The spin-based gyroscope is initialized by optical pumping. When the first medium (e.g. alkali metal atoms) is optically pumping in weak magnetic fields, right (σ ⁺ ) - or left circular (σ ^- ) polarized light is radiated parallel or antiparallel to the bias field B _{0 in} order to selectively create transitions with a difference in the magnetic quantum number of the Zeemann level of plus one or minus one. A representative illustration of the optical pumping of rubidium 87 can be found in 1 and the associated description. The electron spins of the first medium in the vapor cell arrangement are polarized by optical pumping. The bias field specifies a direction about which the polarized electron spins of the first medium precess. By applying the oscillating magnetic field (alternating magnetic field), which has at least one component orthogonal to the direction of the bias field, the precession movement of the polarized electron spins is synchronized around the direction of the bias field, so that all polarized electron spins are in phase with each other with the Larmor frequency (provided there is no external rate of rotation on the spin-based gyroscope) precess around the direction of the bias field. The frequency of the oscillating magnetic field preferably coincides with the Larmor frequency of the polarized electron spins. The magnetic field generating device, which is set up to provide the bias magnetic field and the oscillating magnetic field at the location of the steam cell arrangement, can include, for example, coils, in particular two Helmholtz coils arranged orthogonally to one another.

The precession motion of the polarized electron spins can be converted into a readable electrical signal. For this purpose, the steam cell arrangement can be illuminated, for example, with a linearly polarized read-out laser beam. When passing through the vapor cell arrangement, the polarization of the read-out laser beam is periodically rotated, which is caused by the precession movement of the polarized electron spins of the first medium (Faraday effect). The Faraday effect describes the rotation of the plane of polarization of a linearly polarized electromagnetic wave in a medium when there is a magnetic field in it parallel to the direction of propagation of the wave. The periodic rotation of the polarization of the read-out laser beam can be converted into an electrical signal by a detection arrangement, for example. The detection arrangement can comprise at least one polarizer and at least one detector element, the polarizer being arranged in the beam path between the vapor cell arrangement and the detector element. A radiation sensor based on silicon (Si), germanium (Ge), germanium on silicon, indium gallium arsenide (InGaAs), etc. can be used as the detector element. Photodiodes or bolometers, for example, are also suitable as radiation sensors. Radiation sensors can output an electrical detection signal as a function of a property of the electromagnetic radiation impinging on the radiation sensor, which is a measure of the radiation property. Radiation sensors can measure, for example, a radiation intensity or an energy flux density of the readout light beam transmitted by the vapor cell arrangement. Due to the polarizer, the detector element can detect the polarization rotation of the read-out laser beam, for example as a periodically changing radiation intensity.

The spin precession of two states, which have magnetic quantum numbers Δm _{f of} the same magnitude but opposite signs, Larmor precesses in exactly the opposite direction. If they are exposed to the same bias field B ₀ , they also rotate with the same Larmor frequency | ω _larmor | = | γ B ₀ |, where γ denotes the gyromagnetic ratio. The sign of this rotation has the sign of the magnetic field. Due to the antiparallel bias fields in the two steam cells, the signals from the steam cells, which characterize the precession movement of the electron spins, are thus opposite to one another. The signals cancel each other out, and also when fluctuations in the intensity of the illumination source, for example the laser intensity (if the same pump and readout laser is used for both vapor cells), or the applied magnetic fields occur. If the vapor cells are also initialized by the same resonant alternating magnetic field, the electron spins in the pump areas precess in phase.

If there is no rate of rotation on the spin-based gyroscope, that is, if the system (the spin-based gyroscope) is not rotated from the outside, the detection signal that is captured by the detection arrangement disappears, since this is caused by the electron locks precessing in phase in the first pump area and by the electron pins precessing in phase in the second pump area, which precess in the opposite direction to the electron spins in the first pump area, caused periodically changing magnet cancel field. Furthermore, all the disturbance terms ω _s also disappear, provided that they affect the two pumping areas to the same extent. This enables highly precise calibration, which significantly reduces the drift (signal when there is no rate of rotation). This is also an advantage in signal processing. Furthermore, a correction of manufacturing deviations by calibration is thus advantageously also possible.

If there is an external yaw rate ω _red , this is the same for both cells and does not cancel itself out, but adds up. In this way, a signal is obtained that has been “freed” from disturbance terms that have the same effect on both pumping areas. $${\mathrm{\omega }}_{\text{mess}}=\left(-\left|{\mathrm{\omega }}_{\text{larmor}}+{\mathrm{\omega }}_{\text{S.}}\right|+{\mathrm{\omega }}_{\text{Red}}\right)+\left(\left|{\mathrm{\omega }}_{\text{larmor}}+{\mathrm{\omega }}_{\text{s}}\right|+{\mathrm{\omega }}_{\text{Red}}\right)=2{\mathrm{\omega }}_{\text{Red}}$$

Here, the terms in parentheses stand for the first and the second pump range. It is important that the signal disappears without an external yaw rate / rotation. This offers the advantages mentioned above.

Further advantages are a cost reduction in the production of such a spin-based gyroscope and a reduction in the pack size. In particular, fluctuations in the magnetic field in the area of the steam cell arrangement can be better compensated for, resulting in lower requirements for the magnetic field generating device and internal power sources, as well as lower requirements for shielding against external fields. The same applies to the requirements for laser sources and temperature stabilization.

In one embodiment, the detection device comprises a polarizer and a detection element, in particular a radiation sensor, for detecting a light transmitted by the vapor cell arrangement after passing through the polarizer Bias field is determinable.

In one embodiment, the steam cell arrangement comprises a steam cell, with a buffer gas being arranged in the steam cell which realizes the first pumping area and the second pumping area by spatial restriction of the spin-spin interaction in the steam cell. Due to the buffer gas, the mean free path in the cell is very short, so spins that are spatially separated from one another do not interact. One advantage is that only one steam cell is required, as a result of which it is possible to reduce the size and consequently miniaturization of the spin-based gyroscope without sacrificing sensitivity and reliability. Furthermore, the production costs can be reduced and the production of the spin-based gyroscope can be simplified.

Nitrogen (N), for example, can be used as the buffer gas. Alternatively or in addition, argon (Ar) can be used as a buffer gas.

According to one embodiment, the steam cell arrangement comprises a first steam cell and a second steam cell, wherein the first steam cell comprises the first pump region and the second steam cell comprises the second pump region. Steam cells can advantageously be produced in a very small pack size in a MEMS process. The production in large numbers and the resulting low price is thus possible. As a result, the use of two steam cells is advantageous with regard to miniaturization and cost reduction compared to the use of complex coils and / or shields. Because there are two identical elements (two steam cells), they can be manufactured in the same process and used in one process step. Another important advantage of this embodiment is the compensation of pump laser fluctuations when both pump areas use the same laser as an illumination source.

If both vapor cells are read out by a laser beam, the correction is advantageously carried out very quickly in this embodiment.

A small distance between the steam cells, in particular less than one centimeter, due to the small design, also advantageously enables very good field correction.

Since external interfering influences, provided they are the same for both cells, cancel each other out during detection (see above), it is advantageous to place the first steam cell and the second steam cell close to one another; in particular, the distance between the steam cells should be less than one centimeter (<1 cm). This ensures that external interfering influences are as homogeneous as possible over the area of the steam cells and thus have the same effect, or that the homogeneous and thus intrinsically corrected portion is as large as possible.

The embodiments of the spin-based gyroscope described below advantageously enable the electron spins in the first pump area and in the second pump area to precess in opposite directions to one another, so that external disturbance influences that have the same effect on both pump areas are canceled out during detection. This improves the sensitivity and reliability of the spin-based gyroscope. The following embodiments make use of the fact that reversing the direction of the magnetic field is an alternative to reversing the direction of precession of the electron spins by optical pumping.

According to one embodiment, the lighting arrangement is designed to provide circularly polarized light with at least one component parallel to the direction of the bias field in the first pump area for illuminating the first medium and circularly polarized light with at least one component parallel to the direction in the second pump area for illuminating the first medium of the bias field, the light in the first pump area and in the second pump area being circularly polarized with opposite directions of rotation. Furthermore, the magnetic field generating device is set up to provide the bias field in the first pump area parallel to the bias field in the second pump area.

According to one embodiment, the lighting arrangement is set up in the first pump area to illuminate the first medium, polarized light with at least one component parallel to the direction of the bias field and in the second pump area to illuminate the first medium, circularly polarized light with at least one component parallel to the direction of the Provide bias magnetic field, the light in the first pump area and in the second pump area is circularly polarized with the same direction of rotation. Furthermore, the magnetic field generating device is set up to provide the premagnetization field in the first pump area antiparallel to the premagnetization field in the second pump area.

According to one embodiment, the lighting arrangement is designed to provide circularly polarized light with at least one component parallel to the direction of the bias field in the first pump area for illuminating the first medium and circularly polarized light with at least one component antiparallel to the direction in the second pump area for illuminating the first medium of the bias field, the light in the first pump area and in the second pump area being circularly polarized with the same direction of rotation. Furthermore, the magnetic field generating device is set up to provide the bias field in the first pump area parallel to the bias field in the second pump area.

According to one embodiment, the lighting arrangement is set up to provide circularly polarized light with at least one component perpendicular to the direction of the bias field in the first pump region for illuminating the first medium and circularly polarized light with at least one component perpendicular to the second pump region for illuminating the first medium Provide direction of the bias field, wherein the light in the first pump area and in the second pump area is circularly polarized with the same direction of rotation. The magnetic field generating device is set up to provide the premagnetization field in the first pump area antiparallel to the premagnetization field in the second pump area. The lighting arrangement can be used as part of the detection arrangement for detecting a rotation of the spin-based gyroscope by optically reading out the precession movement of the polarizable electron spins. Another advantage here is that the spin-based gyroscope has a simpler structure.

The illumination arrangement and the detection arrangement can each include an illumination source, such as a laser or a laser diode, in particular a surface emitter (VCSEL) for illumination. Alternatively, the lighting source of the lighting arrangement can also be used as the lighting source of the detection arrangement. For example, further optical elements such as mirrors, polarizers, etc. can be arranged in the beam path. Using a common source of illumination has the advantage of common noise statistics.

• • Erzeugen einer synchronisierten Präzessionsbewegung der polarisierten Elektronenspins im ersten Pumpbereich und Erzeugen einer synchronisierten Präzessionsbewegung der polarisierten Elektronenspins im zweiten Pumpbereich,
• • Optisches Auslesen der Präzessionsbewegungen der polarisierten Elektronenspins im ersten Pumpbereich und im zweiten Pumpbereich

hat den Vorteil, dass Auswirkungen äußerer Störeinflüsse auf das Messergebnis des spinbasierten Gyroskops auf einfache Weise ohne aufwendige und kostenintensive Modifikationen reduziert werden können, um die Sensitivität und Zuverlässigkeit des spinbasierten Gyroskops zu erhöhen und Signaldrifts zu reduzieren.A method for operating the spin-based gyroscope, with the steps:

• • Generation of a synchronized precession movement of the polarized electron spins in the first pump area and generation of a synchronized precession movement of the polarized electron spins in the second pump area,
• • Optical reading of the precession movements of the polarized electron spins in the first pump area and in the second pump area

has the advantage that the effects of external interference on the measurement result of the spin-based gyroscope can be reduced in a simple manner without complex and cost-intensive modifications in order to increase the sensitivity and reliability of the spin-based gyroscope and to reduce signal drift.

This method has some advantages: Dispensing with a noble gas for detecting a rotation of the spin-based gyroscope and instead detecting the rotation of the spin-based gyroscope directly from a change in the precession movement of the polarized electron spins simplifies the system considerably. The fact that no noble gas is required for detection means that the production of the vapor cells can be simplified and, at the same time, pure high-frequency signals can be generated, which simplify signal processing and enable fast signal processing with a high bandwidth despite many filters.

According to one embodiment, during the optical readout, linearly polarized light is irradiated through the vapor cell arrangement and the light transmitted by the vapor cell arrangement is detected.

According to one embodiment, the sum of the precession movements of the polarized electron spins in the first pump area and in the second pump area is detected during the optical readout. In particular, the sum of the precession movements of the polarized electron spins is recorded, with the detection signal disappearing in the event that the spin-based gyroscope does not have an external rate of rotation, because that is caused by the electron spins precessing in phase in the first pump area and that by the electron spins precessing in phase in the second pumping area, which precess in the opposite direction to the electron spins in the first pumping area, cancel out periodically changing magnetic fields. Furthermore, all the disturbance terms ω _s also disappear, provided that they affect the two pumping areas to the same extent.

According to one embodiment, the sum of the precession movements of the polarized electron spins in the first pump area and in the second pump area and the precession movement of the polarized electron spins in the first pump area are recorded separately during the optical readout. One advantage is that both the noisy signal and the intrinsically corrected signal are read out. This gives more information about the system. It enables advanced calibration methods of the spin-based gyroscope, for example, if the system is to be calibrated individually for different influences, it is good to have a signal that contains all the noise terms and thus can be differentiated between them. As a result, a higher precision and drift stability of the spin-based gyroscope can be realized. Another advantage is that not only disturbances that are uniformly present for both vapor cells (signals of the same size with different signs that cancel each other out), but also disturbances that have a gradient between the two pump regions can be corrected. This is due to the fact that the signal of the first pump area and the sum of the signals of both pump areas are known and thus the signal of the second pump area is also implicitly known. Knowing both signals, i.e. H. Both the signal from the first pump area and the signal from the second pump area allow gradients between the pump areas to be corrected, since influences that are not the same for both pump areas, such as the rate of rotation, can be identified. Thus, in this case, advantageously, a system is obtained which is corrected for both gradients and uniform perturbations.

Figure list

Exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the description below. The same reference symbols in the figures denote elements that are the same or have the same effect.

• 1 eine Skizze des Energieschemas eines ersten Mediums, hier Rubidium 87,
• 2 zeigt eine Skizze zur Illustration der Präzessionsbewegungen der polarisierten Elektronenspins im ersten Pumpbereich und im zweiten Pumpbereich,
• 3 zeigt einen beispielhaften Aufbau eines spinbasierten Gyroskops,
• 4 zeigt einen Querschnitt eines Ausschnitts des spinbasierten Gyroskops gemäß einem ersten Ausführungsbeispiel,
• 5 zeigt einen Querschnitt eines Ausschnitts des spinbasierten Gyroskops gemäß einem zweiten Ausführungsbeispiel,
• 6 zeigt einen Querschnitt eines Ausschnitts des spinbasierten Gyroskops gemäß einem dritten Ausführungsbeispiel,
• 7 zeigt einen Querschnitt eines Ausschnitts des spinbasierten Gyroskops gemäß einem vierten Ausführungsbeispiel,
• 8 zeigt einen Querschnitt eines Ausschnitts des spinbasierten Gyroskops gemäß einem fünften Ausführungsbeispiel,
• 9 zeigt einen Querschnitt eines Ausschnitts des spinbasierten Gyroskops gemäß einem sechsten Ausführungsbeispiel und
• 10 zeigt ein Ablaufdiagramm eines Verfahrens zum Betreiben des spinbasierten Gyroskops.

Show it

• 1 a sketch of the energy scheme of a first medium, here rubidium 87,
• 2 shows a sketch to illustrate the precession movements of the polarized electron spins in the first pump area and in the second pump area,
• 3 shows an exemplary structure of a spin-based gyroscope,
• 4th shows a cross section of a section of the spin-based gyroscope according to a first embodiment,
• 5 shows a cross section of a section of the spin-based gyroscope according to a second embodiment,
• 6th shows a cross section of a section of the spin-based gyroscope according to a third embodiment,
• 7th shows a cross section of a section of the spin-based gyroscope according to a fourth embodiment,
• 8th shows a cross section of a section of the spin-based gyroscope according to a fifth embodiment,
• 9 shows a cross section of a detail of the spin-based gyroscope according to a sixth embodiment and
• 10 FIG. 10 shows a flow diagram of a method for operating the spin-based gyroscope.

Embodiments of the invention

1 shows the term scheme 100 of rubidium 87, which can be used, for example, as the first medium in a spin-based gyroscope 200, on the basis of which the optical pumping is explained below. An exemplary structure of the spin-based gyroscope 200 is shown in FIG 3 shown. The energy scheme 100 of rubidium 87 shows a fine structure split, which results from the spin-orbit coupling between the electron spin (S = ± 1/2) and orbital angular momentum. The first excited state has a fine structure split into a first sub-state 117 (5 ² P _1/2 ) and a second sub-state 118 (5 ² P _3/2 ). For an excitation of the rubidium 87 atom from its ground state 116 (5 ² S _1/2 ) into the first substate 117 (5 ² P _1/2 ) an irradiation of light 120 of the wavelength 794.98 nanometers (nm) is necessary. For an excitation of the rubidium 87 atom from its ground state 116 (5 ² S _1/2 ) into the second substate 118 an irradiation of light 119 of the wavelength 780.24 nm is necessary. Furthermore, there is a hyperfine structure split, which results from the nuclear angular momentum. The hyperfine structure splitting is caused by the coupling of the total angular momentum of the electron shell with the angular momentum of the nucleus. The ground state 116 has a hyperfine structure split into an F = 1 state (110) and an F = 2 state (111), the distance 115 between the two energy levels 110, 111 being 6.8 GHz (gigahertz). The first substate 117 splits into a first energy level 112 with F = 1 and a second energy level 113 with F = 2, a distance 114 between the two energy levels 112, 113 being 0.8 GHz.

If the rubidium 87 atom is in an external magnetic field, for example a bias field 300, the energy levels 110, 111, 112, 113 of the hyperfine structure split further (Zeemann splitting), with each energy level 110, 111, 112, 113 having a number of 2F + 1 has sub-levels. For example, the F = 1 energy level 110 of the ground state 116 has three Zeemann levels, the lowest Zeemann level 109 with the magnetic quantum number m _f = -1, the middle Zeemann level with the magnetic quantum number m _f = 0 and the upper Zeemann level 108 are designated with the magnetic quantum number m _f = +1. The F = 2 energy level 111 of the ground state 116 has five Zeemann levels, the lowest Zeemann level 107 being denoted by the magnetic quantum number m _f = -2 and the topmost Zeemann level 105 being _{denoted by m f} = +2. The distance 106 between two neighboring Zeemann levels is ℏω _Larmor , where ω _Larmor corresponds to the frequency of the Larmor precession of the electron spins in the magnetic field caused by the applied magnetic field (in the case of the NMR gyroscope: in the bias field 300).

Analogously, the F = 1 of the first excited state 112 has three Zeemann levels, the lowest Zeemann level 104 with the magnetic quantum number m _f = -1, the middle Zeemann level with the magnetic quantum number m _f = 0 and the upper Zeemann level 103 are designated with the magnetic quantum number m _f = +1. The F = 2 energy level 113 of the first excited state 112 has five Zeemann levels, the lowest Zeemann level 102 being _{denoted by the quantum number m f} = -2 and the topmost Zeemann level 101 being _{denoted by m f} = +2.

In the case of optical transitions, the selection rule Δ m _f = ± 1, 0 _{applies, where Δ m f describes} the difference between the magnetic quantum numbers of the initial and final state. The transitions with Δ m _f = ± 1 can be ^{excited by irradiating circularly polarized σ ±} -polarized light. This polarizes the rubidium. An atom that is in the Zeemann level 105 of the ground state 116 with m _f = 2 (m _f = -2) cannot ^{absorb a σ +} photon (σ ^- photon) because in the first excited state 117 there is no Zeemann Level with m _f = 3 (m _f = -3), which would be necessary for the absorption for reasons of conservation of angular momentum. This means that after a certain pumping time all atoms are in the uppermost (lowest) Zeemann level 105 of the ground state 116 with m _f = 2 (m _f = -2). This corresponds to an alignment of the total spin in the direction of the external magnetic field (in the case of the spin-based gyroscope: the bias field). In other words, by irradiating σ ⁺ light 120 with a wavelength of 794.98 nm, a large part of the rubidium in an ensemble can be pumped into the Zeemann levels of the F = 2 state 113, since, with a powerful pump laser, the population is rapid can be pumped from all states, with the exception of the m _f = 2 state, since no state with Δ m _f = 1 is within reach. Same for m _f = -2 for σ ^- -polarized light and Δ m _f = -1.

2 shows a sketch to illustrate the precession movements of the polarized electron spins 3021, 3022 in the first pump area 2011 and in the second pump area 2012. In 2 A magnetic field direction of a bias magnetic field 300 and a magnetic field direction of an oscillating magnetic field 301 (the oscillation being indicated by a double arrow) are shown, which in this exemplary embodiment are orthogonal to one another. A first arrow 3021 represents a polarized electron spin, for example of rubidium, with the magnetic quantum number m _f = 2, a second arrow 3022 represents a polarized electron spin, for example of rubidium, with the magnetic quantum number m _f = -2. A precession movement 304 of the electron spin 3021 around the bias field 200 with the magnetic quantum number m _f = 2 is opposite to a precession movement 303 of the electron spin 3022 with the magnetic quantum number m _f = -2. The polarized electron spins 3021, 3022 with a magnetic quantum number with the opposite sign can be generated by optical pumping with reverse circularly polarized light, ie σ ⁺ -polarized light for m _f = 2 and σ ^- -polarized light for m _f = -2. The oscillating magnetic field 301 synchronizes the precession movements so that they are in phase with one another but have an opposite direction of rotation, as indicated in the sketch by the two circles 303, 304 with the direction of the arrow reversed. If one reads out the precession movements optically with a laser using the magneto-optical Faraday effect, the direction that is normal to the image plane disappears due to the counter-rotating, synchronized precession movements.

3 shows an exemplary structure of the spin-based gyroscope 200. The NMR gyroscope 200 comprises a steam cell arrangement 201, which is arranged on a heating element 209. Basic sketches of the steam cell arrangement according to various exemplary embodiments are shown in FIGS 2 until 9 and the associated description. A first medium 204, in particular an alkali metal, is arranged in the vapor cell arrangement 201, with the alkali metal being made possible by means of the heating element 209. The steam cell arrangement 201 is surrounded by a magnetic field generating device 206, which provides a static magnetic field, which serves as a bias field 300, and an oscillating magnetic field 301, which has at least one component orthogonal to the bias field 300, at the location of the steam cell arrangement 201. In this embodiment, the
Magnetic field generating device 206 a two-axis Helmholtz coil pair. Alternatively, the magnetic field generating device 206 can comprise three-axis or multi-axis magnetic field coils, for example in order to compensate for interference fields within the steam cell arrangement 201 or different bias fields 3001, 3002 (see e.g. 5 , 6th and 8th ) to be provided for the steam cell arrangement 201. In this exemplary embodiment, a magnetic shield 207 is arranged around the steam cell arrangement 201 in order to shield the steam cell arrangement 201 from surrounding magnetic fields, such as, for example, the earth's magnetic field.
Furthermore, the spin-based gyroscope 200 comprises a lighting arrangement 205 for illuminating the first medium 204 in the vapor cell arrangement 201, the lighting arrangement 205 being set up to polarize electron spins 3021, 3022 of the first medium 204 by optical pumping. The bias magnetic field 300 defines a direction of a precession movement of the polarizable electron spins of the first medium 204, and synchronization of the precession movements of the polarizable electron spins of the first medium 204 is made possible by means of the oscillating magnetic field 301. In this exemplary embodiment, the lighting arrangement 205 comprises a lighting source 2052 for optical pumping and a circular polarizer 2051, the electromagnetic radiation emitted by the lighting source when passing through the circular polarizer 2051 to a circularly polarized light beam as a pump beam 2001 for the first medium 204 arranged in the vapor cell arrangement 201 will. As lighting sources 2052, 2084, for example, lasers or laser diodes, in particular surface emitters (VCSEL) can be used.
The spin-based gyroscope 200 comprises a detection arrangement 208 which is set up to detect a rotation of the spin-based gyroscope 200 about a direction of the bias field 300 from a change in the precession movement of the polarizable electron spins. In this exemplary embodiment, the detection arrangement 208 comprises a linear polarizer 2081 and a readout illumination source 2084, the linear polarizer 2081 being arranged in the beam path between the readout illumination source 2084 and the vapor cell arrangement 201, so that electromagnetic radiation emitted by the readout illumination source 2084 after passing the linear polarizer 2081 hits the vapor cell arrangement 201 as a linearly polarized light beam 2000 and is transmitted 2002 by the latter. Furthermore, the detection arrangement 208 comprises a polarizer 2083 and a detector element 2082, so that, using the magneto-optical Faraday effect, the precession movements of the polarized electron spins of the first medium 204 in the vapor cell arrangement 201 as a measurement signal 2003, for example in the form of an electrical signal, which is a measure for is the periodically changing radiation intensity, can be detected. The measurement signal 2003 is transmitted to a signal processing device 2085, which determines a detection signal 2086 (for example a rate of rotation) of the spin-based gyroscope 200 from the measurement signal 2003. Furthermore, the signal processing device 2085 can be set up to control the fields of the spin-based gyroscope. For example, the signal processing device 2085 can be used to calibrate the spin-based gyroscope by adapting the fields, in particular the magnetic fields 300, 301 or the temperature using the heating element 209, as a function of the measurement signal 2003, so that, for example, in the event that the spin-based gyroscope is not rotated, the measurement signal 2003 disappears (see above). Furthermore, the signal processing device 2085 can be set up for electronic calibration or correction of the measurement signal 2003. The signal processing device 2085 can be designed as part of the spin-based gyroscope 200 or be arranged outside the spin-based gyroscope, the spin-based gyroscope 200 in this case having communication interfaces which, in particular, enable the measurement signals 2003 of the spin-based gyroscope 200 to be transmitted to the signal processing device 2085.

The ones in the 4th until 9 The illustrated exemplary embodiments illustrate the initialization of the two pump regions 2011, 2012, so that partial signals change unequally for the type of external rotation influence of the spin-based gyroscope 200.

• • Verwendung einer Co-Magnetometer-Konfiguration, bei welcher die Zellmagnetisierung verschwindet,
• • Kalibrierung der Effektstärke, da dieser Effekt sich zeitlich nicht ändert, in der Signalverarbeitung,
• • Kompensation durch den Aufbau (Verwenden eines größeren Bereichs, welcher das schwächere Feld sieht, um die Effekte auf dieselbe Größe zu bekommen),
• • Anpassung des Vormagnetisierungsfeldes 300 beispielsweise durch eine magnetische Abschirmung mit diamagnetischen Platten bzw. eine Verstärkung bei der jeweils anderen Dampfzelle 2011a, 2012a mit paramagnetischen Platten 2070, wie dies in 4 gezeigt ist, oder durch eine Korrekturspule, etc.

erfolgen. Die Detektion der Signale (Präzessionsfrequenz) der Dampfzellen 2011a, 2012a über den Detektionslaser 2084 erfolgt üblicherweise über eine magnetooptische Drehung der Laserpolarisation (Faradayeffekt), welche proportional zur Magnetisierung der Elektronenpins des ersten Mediums 204 (welche bei den vorherrschenden Frequenzen oszilliert) in Laserrichtung ist. Die durch das statische angelegte Vormagnetisierungsfeld 300 resultierende Larmor-Präzession, sowie die Präzessionsänderung durch einen beliebigen, für beide Dampfzellen 2011a, 2012a gleichförmigen Störeinfluss, hat also in der ersten Dampfzelle 2011a eine Drehung der Polarisation um einen gewissen Winkel zur Folge. In der zweiten Dampfzelle 2012a erfolgt dann eine Drehung der Polarisation in entgegengesetzter Richtung. Das Messsignal 2003, welches sich aus dem gleichförmigen Störeinfluss ergibt, hebt sich somit auf und verschwindet. Liegt eine Drehrate an, ist diese für beide Dampfzellen 2011a, 2012b gleich und gemessen wird eine Drehung proportional zum Doppelten der Drehrate. 4th shows a cross section of a section of the spin-based gyroscope 200. The steam cell arrangement 201 here comprises a first steam cell 2011a and a second steam cell 2012a, the first medium 204 being arranged in each of the two steam cells. Alternatively (such as in 9 shown), the steam cell arrangement 201 can comprise a steam cell, with a buffer gas being arranged in the steam cell in addition to the first medium 204, which by spatial restriction of the spin-spin interaction in the steam cell realizes the first pump area 2011 and the second pump area 2012. In the in 4th The first steam cell serves as the first pump area 2011 and the second steam cell serves as the second pump area 2012. The bias field 300 in the first pump area 2011 is parallel to the bias field 300 in the second pump area 2012. In particular, the first pump area 2011 and the second pump area 2012 can also are located in the same premagnetization field 300, which is preferably homogeneous in the region of the vapor cell arrangement 201. In this exemplary embodiment, the lighting arrangement 205 is set up to provide circularly polarized light 2001a parallel to the direction of the bias field 300 in the first pump area 2011 for illuminating the first medium 204 and circularly polarized light 2001b parallel to the direction in the second pump area 2012 for illuminating the first medium 204 of the bias field 300, the light 2001a, 2001b being circularly polarized in the first pump area 2011 and in the second pump area 2012 with opposite directions of rotation. For example, the light 2001a is -polarisiert 2011 ⁺ σ for optical pumping of the first pump portion and the light 2001b for the optical pumping of the second pump region 2012 σ ^- -polarisiert. As a result, the two vapor cells 2011a, 2012a are initialized in states with a magnetic quantum number with the opposite sign, i.e. the electron spins of the first medium 204 (e.g. from directly pumped alkali steam: e.g. Rb, Cs, K, Hg) carry out precession movements in opposite directions. For this purpose, one or two lighting sources 2052 with corresponding circular polarizers 2051 can be used in the beam path between the lighting source 2052 and the steam cell arrangement 201. The initialization of the atoms in the cells in different states takes place here by using reversely circularly polarized light 2001a, 2001b. The bias field 300 is preferably the same across both vapor cells 2011a, 2012a. The local magnetization of the steam cell 2011a, 2012a can result in an inequality of the magnetic fields of the two steam cells 2011a, 2012a. Preferably this is corrected to in the two Steam cells 2011a, 2012a to get exactly the same frequency of the precession movement. The correction can for example by

• • Use of a co-magnetometer configuration in which the cell magnetization disappears,
• • Calibration of the effect strength, since this effect does not change over time, in the signal processing,
• • Compensation by construction (using a larger area that sees the weaker field in order to get the effects on the same size),
• • Adaptation of the bias field 300, for example, by magnetic shielding with diamagnetic plates or reinforcement in the respective other steam cell 2011a, 2012a with paramagnetic plates 2070, as shown in FIG 4th shown, or by a correction coil, etc.

respectively. The detection of the signals (precession frequency) of the vapor cells 2011a, 2012a via the detection laser 2084 usually takes place via a magneto-optical rotation of the laser polarization (Faraday effect), which is proportional to the magnetization of the electron pins of the first medium 204 (which oscillates at the prevailing frequencies) in the laser direction. The Larmor precession resulting from the static applied bias field 300, as well as the change in precession due to any interference influence that is uniform for both steam cells 2011a, 2012a, thus results in a rotation of the polarization by a certain angle in the first steam cell 2011a. In the second vapor cell 2012a, the polarization is then rotated in the opposite direction. The measurement signal 2003, which results from the uniform interference, cancels out and disappears. If there is a rate of rotation, it is the same for both steam cells 2011a, 2012b and a rotation is measured proportional to twice the rate of rotation.

5 FIG. 11 shows a cross section of a section of the spin-based gyroscope 200, the structure being the same as that in FIG 4th is the structure shown. A difference to the in 4th The embodiment shown, in which signals are generated in different directions of precession by differently pumped states, is that in 5 the magnetic field direction of the bias field 300 at the location of the first pumping area 2011 and the magnetic field direction of the biasing field 3002 at the location of the second pumping area 2012 are antiparallel to each other and the light 2001a for optically pumping the first pumping area 2011 σ ⁺ -polarized and the light 2001b for optically pumping the second Pump area 2012 also σ + -polarized, the radiation directions each being parallel to the associated bias field 3001, 3002 of the pump areas 2011, 2012 and thus antiparallel to one another. The 2011, 2012 pumping areas are in 5 realized as two separate steam cells. Alternatively, the two pump areas 2011, 2012 can also be implemented in a steam cell (see 9 ), wherein a buffer gas is arranged in the steam cell, which realizes the first pump area 2011 and the second pump area 2012 through spatial restriction of the spin-spin interaction in the steam cell. The two bias fields 3001, 3002 in 5 can be generated, for example, by different coil pairs which are part of the magnetic field generating device 206, each steam cell 2011a, 2012a being assigned its own coil pair for generating the respective bias field 3001, 3002. Noise resulting from the generation of the magnetic field can also be canceled if a common power source is used. This applies to most internal sources of disturbance and to external disturbance variables, such as temperature change, which are uniform over both pump areas in 2011, 2012. In this exemplary embodiment, external interference fields are corrected using external shields, such as magnetic shield 207 (see, for example, FIG 3 ), since otherwise they can no longer be distinguished from a rotation. In this exemplary embodiment, the electron pins are initialized in opposing precession movements by applying anti-parallel bias fields 3001, 3002 can generate a stable magnetic field can be reduced.

6th FIG. 4 shows a cross-section of a section of the spin-based gyroscope 200, the structure with that from FIG 5 shown embodiment coincides except for the lighting arrangement 205. A difference to the in 5 The embodiment shown is in particular that in the in 6th illustrated embodiment, only one illumination source 2052, 2084 is used to enable optical pumping and readout. In particular, a laser for the pumping and readout process is used as the illumination source 2052, 2084 with a circular polarizer connected downstream, with σ + -polarized light being generated, for example. This is possible by adapting the detection method (see above M _z mode vs M _x mode). This embodiment is characterized by a very compact and simple structure.

7th FIG. 4 shows a cross-section of a section of the spin-based gyroscope 200, the structure with that from FIG 4th The embodiment shown matches, with a beam splitter 210 additionally being arranged in the beam path between the first steam cell 2011a and the second steam cell 2012a, which splits the readout light beam 2000 (linearly polarized light) into two partial beams, a first partial beam after passing through the second steam cell 2012a and of the first polarizer 2083a impinges on the first detector element 2082a and wherein a second partial beam impinges on a second detector element 2082b after passing through a second polarizer 2083b. The first detector element 2082a thus detects the sum of the signals from the two vapor cells 2011a, 2012a in which disturbance terms cancel out due to the opposing precession movements of the electron spins (see above). However, the second detector element 2082b only detects the signal from the first vapor cell 2011a, which still contains all the disturbance terms. This knowledge enables advanced calibration methods: For example, if the system is to be calibrated individually for different influences, it is good to have a signal that contains all the noise terms and thus can be differentiated between them. This enables higher precision and drift stability to be achieved. A great advantage of this exemplary embodiment is that not only disturbances present uniformly for both cells (signals of the same size with different signs which cancel each other out), but also gradients can be corrected. By subtracting the detected signal of the second detector element 2082b from the measurement signal 2003 of the first detector element 2082a, the signal of the second vapor cell 2012a is obtained. Both the noisy signals of the two steam cells 2011a, 2012a and the intrinsically corrected measurement signal 2003, which results from the sum of the two signals, are thus known. Knowing all these signals allows gradients between the cells to be corrected, since influences which are not the same for both cells, such as the rate of rotation, can be identified. In this exemplary embodiment, a spin-based gyroscope 200 is thus obtained which can be corrected with regard to gradients and uniform disturbances.

8th FIG. 4 shows a cross-section of a section of the spin-based gyroscope 200, the structure with that from FIG 5 The embodiment shown matches and the optional paramagnetic plates 2070 are also arranged on the second pump area 2012 and a beam splitter 210 is arranged in the beam path between the first steam cell 2011a and the second steam cell 2012a, which splits the readout light beam 2000 (linearly polarized light) into two partial beams , with a first partial beam impinging on the first detector element 2082a after passing through the second vapor cell 2012a and the first polarizer 2083a and with a second partial beam impinging on a second detector element 2082b after passing through a second polarizer 2083b. The first detector element 2082a thus detects the sum of the signals from the two vapor cells 2011a, 2012a in which disturbance terms cancel out due to the opposing precession movements of the electron spins (see above). However, the second detector element 2082b only detects the signal from the first vapor cell 2011a, which still contains all the disturbance terms. In this exemplary embodiment, instead of optical pumping in different states by reversely circularly polarized light, the magnetic field directions of the bias fields 3001, 3002 for the two pump areas 2011, 2012 are reversed, that is, antiparallel to one another, as indicated by the arrows pointing in the opposite direction in 5 and 8th is indicated. Noise from these fields can be further corrected if they use the same power source. Since both the sum of the signals and the individual signals are known in this exemplary embodiment, an extensive correction of external disturbance variables is also possible here. For example, if the system is to be individually calibrated for different influences, it is good to have a signal that contains all the noise terms and can thus be differentiated between them. This enables higher precision and drift stability to be achieved. A great advantage of this exemplary embodiment is that not only disturbances present uniformly for both cells (signals of the same size with different signs which cancel each other out), but also gradients can be corrected. By subtracting the detected signal of the second detector element 2082b from the measurement signal 2003 of the first detector element 2082a, the signal of the second vapor cell 2012a is obtained. Both the rapidly affected signals of the two steam cells 2011a, 2012a and the intrinsically corrected measurement signal 2003, which results from the sum of the two signals, are thus known. Knowledge of both signals allows gradients between the cells to be corrected, since influences which are not the same for both cells, such as the rate of rotation, can be identified. In this exemplary embodiment, a spin-based gyroscope 200 is thus obtained which can be corrected with regard to gradients and uniform disturbances.

9 FIG. 10 shows a cross section of a section of the spin-based gyroscope 200, the steam cell arrangement 201 in this exemplary embodiment comprising a steam cell 2013 which includes the first pump area 2011 and the second pump area 2012. In this case, a buffer gas is arranged in the steam cell 2013, which realizes the first pump area 2011 and the second pump area 2012 through spatial restriction of the spin-spin interaction in the steam cell 2013. The Pumpbe rich 2011, 2012 are in the 8th indicated by dashed circles. Furthermore, only one illumination source 2052 is required for optical pumping, since the light beam after passing through the first pumping area 2011 through optical elements (in 9 not shown), such as, for example, a mirror, in particular a micromirror, is deflected and runs antiparallel to the direction of irradiation in the first pump area 2011 through the second pump area 2012. This makes use of the fact that a right circularly polarized laser against the static bias field 300 is equal to a left circularly polarized laser along the bias field 300 (usually a superposition of both is used for AC Stark compensation).

The ones in the 4th until 8th Instead of having two lighting sources 2052 for optical pumping, the exemplary embodiments shown can all also have only one lighting source, analogous to the use in FIG 9 will be realized.

Alternatively or in addition, the 4th until 8th Embodiments shown with two steam cells 2011a, 2012a analogous to 9 with a steam cell 2013 in which a buffer gas is arranged so that both pump areas 2011, 2012 can be generated in a steam cell 2013. The following applies: If steam cells 2013 are used with buffer gas, the spin interactions are limited spatially (depending on the gas used and its pressure. The buffer gas can be, for example, nitrogen (N ₂ ), argon (Ar) or a mixture of nitrogen (N ₂ ) and Argon (Ar) is used with pressures between a few 10 Torr and a few 100 Torr, in particular 45 Torr to 450 Torr. It is therefore possible to use only one steam cell 2013 with differently pumped areas 2011, 2012 instead of two steam cells 2011a, 2012a.

10 shows a flowchart of a method sequence 400 for operating the spin-based gyroscope 200. The method 400 comprises the step: generating 401 a synchronized precession movement of the polarized electron spins in the first pump area 2011 and generating 401 a synchronized precession movement of the polarized electron spins in the second pump area 2012. The polarization of the electron spins takes place in particular by optically pumping the electron spins 3021, 3022 of the first medium 204. The precession movement of the electron spins is synchronized by irradiating the oscillating magnetic field 301, which has at least one component orthogonal to the magnetic field direction of the bias field 300, 3001, 3002. Furthermore, the method 400 comprises the step: Optical readout 402 of the precession movements of the polarized electron spins in the first pump area 2011 and in the second pump area 2012. During optical readout, linearly polarized light 2000 can be irradiated through the vapor cell arrangement 201 and the detection of the vapor cell arrangement 201 transmitted light take place in 2002. The direction of incidence of the readout light beam 2000 has at least one component orthogonal to the magnetic field direction of the bias field 300, 3001, 3002. During the optical readout, the sum of the precession movements of the polarized electron spins in the first pump area 2011 and in the second pump area 2012 can be recorded. The measurement signal 2003 is transmitted to a signal processing device 2085, which can determine a detection signal 2086 (for example a rate of rotation) of the spin-based gyroscope 200 from the measurement signal 2003 (see above). Reads a readout illumination source 2084 from the two pump areas 2011, 2012, which are generated by spin precession signals, which are in phase (the direction of readout must be taken into account here, as the signal always adds twice in one direction, whereas in the direction perpendicular to it disappears, see 2 ) are characterized with the same cause of precession but the opposite direction of precession, an optimized signal is obtained which has less interference. Alternatively or additionally, the sum of the precession movements of the polarized electron spins in the first pump area 2011 and in the second pump area 2012 and the precession movement in the first pump area 2011 can be recorded separately (for example by means of the spin-based gyroscope from the exemplary embodiments in FIG 8th and 9 ).

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• CN 109737945 A [0001]

Non-patent literature cited

• "MEMS Components for NMR Atomic Sensors" (R. M. Noor and A. M. Shkel; Journal of Microelectromechanical Systems, 27 (6): 1148-1159, Dec. 2018) [0004]

Claims (12)

Spin-based gyroscope (200), comprising • a steam cell arrangement (201) comprising a first medium (204) which is arranged in the steam cell arrangement (201), • a lighting arrangement (205) for illuminating the first medium (204) in the steam cell arrangement ( 201), the lighting arrangement (205) being set up to polarize electron spins (3021, 3022) of the first medium (204) by optical pumping, a magnetic field generating device (206) for providing a bias field (300) and an oscillating magnetic field (301 ) at the location of the vapor cell arrangement (201), the bias field (300) for establishing a direction of a precession movement of the polarizable electron spins of the first medium (204) and the oscillating magnetic field (301) for synchronizing the precession movements of the polarizable electron spins of the first medium (204) are set up and • a detection arrangement (208) for detecting a rotation of the spin-based gyroscope (200) is set up around a direction of the bias field (300) from a change in the precession motion of the polarizable electron spins, characterized in that the vapor cell arrangement (201) has a first pump area (2011) and a second pump area (2012), whereby in the first pumping area (2011) a precession movement of the polarizable electron spins located in the first pumping area (2011) can be generated with a first direction of rotation second direction of rotation can be generated and • wherein the first direction of rotation and the second direction of rotation are opposite to one another. Spin-based gyroscope (200) according to Claim 1 , characterized in that the detection arrangement (208) comprises a polarizer (2083) and a radiation sensor (2082) for detecting a light (2002) transmitted by the vapor cell arrangement (201) after passing through the polarizer (2083), wherein from the measurement data ( 2003) of the radiation sensor (2082), a rotation frequency of the rotation of the spin-based gyroscope (200) around a direction of the bias field (300) can be determined. Spin-based gyroscope (200) according to one of the preceding claims, characterized in that the steam cell arrangement (201) comprises a steam cell (2013), wherein a buffer gas is arranged in the steam cell (2013), which by spatial restriction of the spin-spin interaction in realized the first pumping area (2011) and the second pumping area (2012) of the steam cell. Spin-based gyroscope (200) according to one of the Claims 1 or 2 , characterized in that the steam cell arrangement (201) comprises a first steam cell (2011a) and a second steam cell (2012a), wherein the first (2011a) steam cell comprises the first pump area (2011) and the second steam cell (2012a) comprises the second pump area ( 2012) includes. Spin-based gyroscope (200) according to one of the Claims 1 until 4th , characterized in that • that the lighting arrangement (205) is set up in the first pump area (2011) for illuminating the first medium (204) circularly polarized light (2001a) parallel to the direction of the bias field (300) and in the second pump area (2012 ) to provide circularly polarized light (2001b) parallel to the direction of the bias field (300) for illuminating the first medium (204), the light being circularly polarized in opposite directions in the first pump area (2011) and in the second pump area (2012) and • that the magnetic field generating device (206) is set up to provide the bias field in the first pump area (2011) parallel to the bias field in the second pump area (2012). Spin-based gyroscope (200) according to one of the Claims 1 until 4th , characterized in that • that the lighting arrangement (205) is set up in the first pump area (2011) to illuminate the first medium (204) circularly polarized light parallel to the direction of the bias field and in the second pump area (2012) to illuminate the first medium (204) to provide circularly polarized light parallel to the direction of the bias field, the light in the first pump area (2011) and in the second pump area (2012) being circularly polarized with the same direction of rotation and that the magnetic field generating device (206) is set up to generate the bias field in the ers th pumping area (2011) antiparallel to the bias field in the second pumping area (2012). Spin-based gyroscope (200) according to one of the Claims 1 until 4th , characterized in that • that the lighting arrangement (205) is set up in the first pump area (2011) to illuminate the first medium (204) circularly polarized light parallel to the direction of the bias field and in the second pump area (2012) to illuminate the first medium (204) to provide circularly polarized light antiparallel to the direction of the bias field, the light in the first pump area (2011) and in the second pump area (2012) being circularly polarized with the same direction of rotation and that the magnetic field generating device (206) is set up to generate the bias field in the first pump area (2011) parallel to the bias field in the second pump area (2012). Spin-based gyroscope (200) according to one of the Claims 1 until 4th , characterized in that • that the lighting arrangement (205) is set up in the first pump area (2011) to illuminate the first medium (204) circularly polarized light perpendicular to the direction of the bias field and in the second pump area (2012) to illuminate the first medium (204) to provide circularly polarized light perpendicular to the direction of the bias field, the light in the first pump area (2011) and in the second pump area (2012) being circularly polarized with the same direction of rotation, • that the magnetic field generating device (206) is set up to generate the bias field in the first pump area (2011) antiparallel to the bias field in the second pump area (2012), and • that the lighting arrangement (205) as part of the detection arrangement (208) for detecting a rotation of the spin-based gyroscope (200) by optically reading the precession movement of the polarizable electron spins applicable is. Method (400) for operating the spin-based gyroscope (200) according to one of the preceding claims, comprising the steps: • Generating (401) a synchronized precession movement of the polarized electron spins in the first pumping area (2011) and generating (401) a synchronized precession movement of the polarized electron spins in the second pumping area (2012), • Optical readout (402) of the precession movements of the polarized electron spins in the first pump area (2011) and in the second pump area (2012). Method (400) according to Claim 9 , wherein during the optical readout, linearly polarized light (2000) is irradiated through the vapor cell arrangement (201) and the light transmitted (2002) by the vapor cell arrangement (201) is detected. Method (400) according to one of the Claims 9 or 10 , whereby the sum of the precession movements of the polarized electron spins in the first pump area (2011) and in the second pump area (2012) is recorded during the optical readout. Method (400) according to one of the Claims 9 until 11th , whereby the sum of the precession movements of the polarized electron spins in the first pump area (2011) and in the second pump area (2012) and the precession movement of the polarized electron spins in the first pump area (2011) are recorded separately.

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