JP2020113616A - Quantum optical device - Google Patents

Abstract

To provide a quantum optical device capable of temperature control for maintaining a semiconductor element group including a light emitting element and a light receiving element at a temperature lower than that of a gas cell.SOLUTION: A gas cell 20 controlled to a high temperature by temperature raising means 30 is spaced apart from a first tether 12a to which a light emitting element 51 is fixed via a first heat insulator 41 and is spaced apart from a second tether 12b to which a light receiving element 52 is fixed via a second heat insulator 42. In a quantum optical device 1A, due to the temperature gradient generated through the first and second heat insulators 41 and 42, the temperature of the light emitting element 51 and the light receiving element 52 can be prevented from rising, and temperature control with a low temperature control system can be performed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a quantum optical device that can be used in an atomic clock or the like that obtains a stable standard frequency signal by utilizing the interaction between a laser and an atom.

In a quantum optical device such as an atomic clock, a stable standard frequency signal is acquired from a gaseous alkali metal element, a rare gas or an inert gas by utilizing the interaction between a laser and an atom. In a quantum optical device, a gas filling container (gas cell) in which a gas is sealed and sealed is indispensable, and for example, a gas cell using a glass tube is generally used. In addition, it is known that the absorption line of an atom that becomes a standard frequency signal is sensitive to a magnetic field and angular acceleration, and by utilizing this property for highly sensitive detection of momentum, an atomic compass and an atomic gyro can be constructed. You can also In recent years, due to a strong demand for miniaturization of quantum optical devices, many developments of small gas cells using a wafer process such as anodic bonding and plasma etching have been reported.

As an example of the quantum optical device as described above, a schematic configuration of a CPT (Coherent Population Trapping) type quantum optical device 100 is shown in FIG. The constant current supplied from the current driver 101 is supplied to the light emitting element 4 via the bias tee 102 together with the high frequency modulation signal from the microwave oscillator 103. By applying a constant current to the light emitting element 104, the light emitting element 104 emits light at a constant frequency ν ₀ . When superimposing a high frequency modulated signal comprising vibration frequency [nu _mod the current the applied from the microwave oscillator 103, the light emitting element from _{104 ν 0 -ν mod, ν 0mod} , light having a frequency of ν ₀ + ν _mod is generated The light received by the light receiving element 106 is input to the gas cell 5 and passed through the optical path OP. In addition, although the higher order term of ν _mod is actually generated, its influence is negligible, so in the following, only three frequencies that are vigorously generated will be focused.

The gas cell 5 is filled with a gaseous alkali metal element together with an inert rare gas serving as a buffer gas, and the CPT phenomenon occurs due to mutual interference between light and atoms. As shown in FIG. 11, the CPT phenomenon is a three-level system consisting of two ground levels (<1| and <2|) and one excitation level (<3|) that are in the forbidden band with each other. This is an observed resonance phenomenon. When the first excitation light ExL1 corresponding to the energy difference between <3| and <1| is introduced into the gas cell 105 exhibiting this three-level system, an absorption/emission phenomenon associated with stimulated absorption and stimulated emission is observed. Similarly, when the second excitation light ExL2 corresponding to the energy difference between <3| and <2| is introduced into the gas cell 105, an absorption/emission phenomenon associated with stimulated absorption and stimulated emission is observed. Here, when the first excitation light ExL1 and the second excitation light ExL2 are simultaneously introduced into the gas cell 105, the induced absorption and the stimulated emission between the respective energy levels are canceled out, and the interaction with the excitation light does not occur. Dark resonance is observed. This is called the CPT phenomenon or CPT resonance.

Therefore, when two of the plurality of frequencies input to the gas cell 105 having the energy level as shown in FIG. 11 match the first excitation light ExL1 and the second excitation light ExL2, the CPT phenomenon occurs. From this, by appropriately selecting the output frequency ν ₀ of the light emitting element 105 in the steady state, it is possible to control the expression of the CPT phenomenon by using the output frequency ν _mod of the microwave oscillator 103 which is an external input. Recognize.

The appearance of the CPT phenomenon maximizes the amount of light transmitted through the gas cell 105 and maximizes the output of the light receiving element 106. Further, the temperature of the gas component enclosed in the gas cell 105 is controlled by the temperature raising means 107 such as a heater to a high temperature so that the gas component is kept in a gaseous state, and is supported at a fixed position by the supporting means 108. An example of the supporting means 107 is shown in FIG. The main frame 1081 supports the first tether 1082a and the second tether 1082b, and the first and second tethers 1082a and 1082b fix the gas cell 105, the light emitting element 104, and the light receiving element 106 in place.

The support means 108 stably holds the arrangement in which the laser light passes through the gas cell 105 through the optical path OP from the light emitting portion of the light emitting element 104 toward the light receiving portion of the light receiving element 106. Then, the output frequency of the microwave oscillator 103 is feedback-controlled so that the output of the light receiving element 105 is always captured by using the discriminator 109 and the loop filter 110. That is, the high frequency modulation signal that is the output of the microwave oscillator 103 is stabilized by the energy level of the atoms in the gas cell 105 so that the desired output frequency is obtained. As described above, the functional means for capturing the CPT resonance can be configured by one or more semiconductor elements miniaturized by the semiconductor manufacturing process. It is also possible to package all functions and configure one semiconductor device. The quantum optical unit and the CPT resonance capturing function described above are housed in a decompressed closed container 111.

The quantum optical unit of the quantum optical device 100 is a device that can obtain a standard frequency signal on the assumption that the gas cell 105 is shielded by a magnetic shield or the like and that no acceleration motion is applied to the entire device. However, when magnetism or inertial motion is applied, the energy level also reacts sensitively, and the output frequency fluctuates accordingly. Therefore, as in the quantum optical device 100 ′ shown in FIG. 13, by extracting the output signal S on which external magnetism is applied, it can be used as an atomic compass. Further, as in the quantum optical device 100″ shown in FIG. 14, the comparator 113 compares the standard frequency signal to which the acceleration motion has been applied with the reference clock from the reference clock source 112, and extracts the output signal S of the difference wavelength. By doing so, it can be used as an atomic gyro.

The gas cell 105 in the quantum optics unit needs to be temperature-controlled at about 60 to 90° C. in order to hold the encapsulated alkali metal element in a gaseous state. This is to increase the momentum of atoms and increase the number of atoms that mutually interact with light in a molecular kinetic theory. Therefore, a heat conducting member is provided across the light source side (light emitting element) and the light detecting section side (light receiving element) with respect to the atomic cell (gas cell), and the temperature control of the gas cell, the light emitting section, and the light receiving section is performed integrally. An optical unit has been proposed (for example, see Patent Document 1).

JP, 2017-183869, A

However, in the quantum optical unit described in Patent Document 1, since the light emitting element, the light receiving element, and the semiconductor element having a function of capturing the CPT resonance are also mounted and mounted on the gas cell, the temperature control of the gas cell and the temperature control of the semiconductor element group are performed. Cannot be done individually. It is desirable that each semiconductor element such as a light emitting element and a light receiving element has a temperature characteristic in its output, and is constantly controlled to a temperature suitable for the characteristics of the semiconductor. Further, from the viewpoint of controllability of temperature, it is desirable to maintain the temperature above room temperature. From the viewpoint of device life and noise, when general-purpose components are used for these semiconductor device groups, the upper limit of constant temperature control is 40 to 60°C. It is preferable to set it to a degree. As described above, the temperature zone for constant temperature control differs between the gas cell and the semiconductor element group, but in the quantum optics unit described in Patent Document 1, the temperature zone is controlled collectively in the temperature zone of the gas cell, and from the viewpoint of the life and characteristics of the device, This is an obstacle to miniaturization and practical application of quantum optical devices. In particular, when using a small gas cell filled with gas in a minute inner space created by the wafer process and a minute light emitting and receiving element or semiconductor element corresponding to that size, the gas cell controlled at high temperature emits and receives light. Heat conduction to devices and semiconductor devices poses a serious problem.

The mismatch of the management temperature between the gas cell and the semiconductor element group is apt to cause deterioration of the light emitting element and the light receiving element, which shortens the life of the device. Of course, it is possible to design the light emitting element and the light receiving element so as to operate at high temperature in the heat retaining temperature zone of the gas cell, but in this case, the increase in cost is inevitable. In addition, in a quantum optical device such as an atomic clock, other semiconductor elements for peripheral circuits must be mounted at high density. It is desirable that these semiconductor element groups are also stacked and mounted on the light emitting element and the light receiving element. In this case, if the semiconductor element group is subjected to high temperature control in the temperature zone of the gas cell, the life and performance of the quantum optical device will be shortened. Further manifest.

Therefore, an object of the present invention is to provide a quantum optical device capable of performing temperature control for maintaining a semiconductor element group including a light emitting element and a light receiving element at a temperature lower than that of a gas cell.

In order to solve the above problems, a light-emitting element that emits excitation light of a plurality of frequencies in the absorption wavelength band of an alkali metal element, and the excitation light from the light-emitting element is arranged at a position to receive the excitation light from a transparent window portion, and by a wafer process. The small gas filling container in which the alkali metal element and the buffer gas are filled in the created fine inner space, and the gas filling container is kept at a high temperature so that the gas component filled in the gas filling container maintains a gas state. Temperature raising means for heating to, a light receiving element arranged at a position for receiving the light passing through the gas filling container, and a CPT for maximizing the light intensity detected by the light receiving element. At least one semiconductor element having a function of performing CPT resonance trapping in which the frequency difference of the excitation light output from the light emitting element so as to generate resonance matches the frequency difference between the base ranks in the alkali metal element; And a heat insulating unit interposed between the light emitting element and the gas filling container and between the light receiving element and the gas filling container.

Moreover, in the said structure, the said heat insulation means may be a heat insulating material with low thermal conductivity.

Moreover, in the said structure, the said heat insulation means may make the cross-sectional area of a heat conduction path small, and may make the distance of a heat conduction path long.

Further, in the above configuration, a heat shield means may be provided to suppress the radiation from the temperature raising means of the gas filling device acting on the light emitting element, the light receiving element and the semiconductor element.

Further, in the above configuration, at least one of the light emitting element, the light receiving element, and the semiconductor element may carry out temperature management by a unique temperature control system.

Further, in the above structure, at least one of the light emitting element, the light receiving element, and the semiconductor element is provided with an element temperature detecting means for detecting the temperature of the element, and the temperature detected by the element temperature detecting means is acquired, A temperature management unit may be provided to stop the temperature raising unit when the detected temperature exceeds an upper limit reference temperature defined with reference to a temperature range in which the element can stably operate.

According to the quantum optical device of the present invention, at least the light emitting element and the light receiving element are kept at a temperature lower than that of the gas-filled container by the temperature gradient generated through the heat insulating means. The temperature can be controlled to be maintained at. As a result, it is expected that the quantum optical device will have a long life and suppression of performance degradation.

It is a schematic block diagram of the quantum optical device which concerns on 1st Embodiment. The gas cell of the 1st modification is shown, (A) is an external perspective view, (B) is a sectional view taken along the line IIB-IIB of FIG. 2(A), and (C) is IIC-IIC of FIG. 2(A). It is the arrow sectional drawing of a line. The gas cell of the 2nd modification is shown, (A) is an external perspective view, (B) is a sectional view taken along the line IIIB-IIIB of FIG. 3(A), and (C) is IIIC-IIIC of FIG. 3(A). It is the arrow sectional drawing of a line. The gas cell of the 3rd modification is shown, (A) is an external perspective view, (B) is a cross-sectional view taken along the line IVB-IVB in FIG. 4(A), and (C) is IVC-IVC in FIG. 4(A). It is the arrow sectional drawing of a line. (A) is a schematic cross-sectional view in which the gas-filled space in the gas cell of the first modified example is increased. (B) is a schematic cross-sectional view in which the gas-filled space in the gas cell of the second modified example is increased. FIG. 13C is a schematic E step view in which the gas-filled space in the gas cell of the third modified example is increased. (A) is an external view showing a heat insulating means of a frame structure. (B) is an external view showing a heat insulating means having a spiral structure. It is a schematic block diagram of the quantum optical device which concerns on 2nd Embodiment. It is a schematic block diagram of the quantum optical device which concerns on 3rd Embodiment. It is a schematic block diagram of the quantum optical device which concerns on 4th Embodiment. It is a functional block diagram which shows the conventional quantum optical device applicable to an atomic clock. It is a principle explanatory view of a CPT phenomenon. It is a schematic block diagram of the conventional quantum optical device. It is a functional block diagram which shows the conventional quantum optical device applicable to an atomic compass. It is a functional block diagram which shows the conventional quantum optical device applicable to an atomic gyro.

Next, quantum optical devices of various embodiments will be described in detail with reference to the accompanying drawings.

The quantum optical device 1A according to the first embodiment shown in FIG. 1 has a structure in which the quantum optical unit 3A is provided in the decompressed closed container 2. The supporting means 10A of the quantum optics part 3A holds the gas cell 20 which is a gas filling container in which an alkali metal element is sealed in a predetermined position. Around the gas cell 20, there is arranged a temperature raising means 30 which can be constituted by a heater or the like for holding the enclosed gas in a gaseous state (for example, holding a high temperature of 60 to 90° C.). The gas cell 20 is not directly supported by the supporting means 10A, but is supported by the heat insulating means 40A. A light emitting element 51 is arranged on one side of the heat insulating means 40A, and a light receiving element 52 is arranged on the other side, and an optical path OP is formed in which irradiation light from the light emitting element 51 reaches the light receiving portion of the light receiving element 52 through the gas cell 20. ..

It is assumed that the light emitting element 51 and the light receiving element 52 having the semiconductor element structure perform temperature management by a unique temperature control system different from the gas cell 20. Therefore, the temperature management means 60 is provided and the temperature management control of the light emitting element 51 and the light receiving element 52 is implemented. The light emitting element 51 is provided with an element heating means 61 for heating to a temperature lower than the temperature raising means 30 provided in the gas cell 20 (for example, 40 to 60° C.), and the light receiving element 52 is similarly provided in the gas cell 20. Element heating means 62 for heating to a temperature lower than the temperature raising means 30 provided is provided. The temperature of the light emitting element 51 necessary for temperature management is detected by the first element temperature detecting means 63, and the temperature of the light receiving element 52 is detected by the second element temperature detecting means 64, and the detected information is the temperature managing means 60. Entered in.

The temperature management means 60 can be configured by a semiconductor element or the like provided in the vicinity of the light emitting element 51 and the light receiving element 52, or on the same substrate. Although not shown in FIG. 1, in order to realize a function necessary for acquiring a standard frequency signal or the like using the CPT phenomenon, in the vicinity of the light emitting element 51 and the light receiving element 52 or on the same substrate. A semiconductor element is also provided. Hereinafter, the light emitting element 51, the light receiving element 52, and other semiconductor elements may be collectively referred to as a semiconductor element group.

The temperature raising means 30 of the gas cell 20 may perform temperature control by a control function provided separately from the temperature control means 60, or the temperature control means 60 may control the temperature raising means 30. The gas cell 20 has a structure in which a gas-filled empty portion 22 that penetrates two surfaces (an upper surface and a lower surface in FIG. 1) of a base body 21 and is sealed by a light-transmissive first face plate 23a and a second face plate 23b. Is. For example, by disposing the first face plate 23a of the gas cell 20 so as to face the light emitting element 51, this is the incident face, and by disposing the second face plate 23b so as to face the light receiving device 52, this is the emitting face. To do. The temperature raising means 30 heats the gas filled in the gas filling space 22 of the gas cell 20 in order to keep the gas in a gaseous state. The temperature raising means 30 emits light from the entrance window of the first face plate 23a and the second face plate 23b. Care must be taken that the window is not blocked by the temperature raising means 30. Alternatively, a heater made of a transparent conductive film (ITO film) transparent to the wavelength of the laser light may be arranged so as not to obstruct the optical path OP.

For the base body 21 of the gas cell 20 described above, an existing glass tube can be cut into a required length and the inner space of the single glass tube can be used as the gas-filled space 22. There is a limit to miniaturization of the gas cell 20. If the base body 21 is created by finely processing a base material such as silicon by a wafer process, the main body of the gas cell 20 can be formed in a small size of several millimeters or less. Being able to use the wafer process means that small gas cells 20 such as semiconductor chips can be mass-produced. In addition, if semiconductor production technology can be utilized, pattern transfer using an exposure apparatus will open the way for further miniaturization of the gas cell 20. In addition, if the base body 20 of the gas cell 20 is made of a smooth wafer, a technique called wafer level packaging can be used to assemble at the wafer level and dicing at the end to separate the individual pieces. Is.

Further, the small gas cell 20 is not limited to the structure described above. For example, the gas cell 20A of the first modified example shown in FIG. 2 has a pair of base bodies 24, 24 each having a required shape (for example, a substantially quadrangular shape) and a flat plate, and the inner cavity opening surface of the light transmissive body 25. Is sealed and a gas-filled void 22 is provided. The light transmissive body 25 has a substantially rectangular frame shape formed of a translucent material such as glass and has a pair of translucent wall portions 25a and 25b facing each other and a pair of connecting portions for connecting end portions of the translucent wall portions 25a and 25b. It is provided with walls 25c and 25d. In the gas cell 20A shown in FIG. 2, the light transmitting wall portion 25a is on the emitting side and the light transmitting wall portion 25b is on the incident side. Therefore, the outer surface and the inner surface of the light transmitting wall portions 25a and 25b are planes orthogonal to the optical path OP. I need to put it. On the other hand, such accuracy is not required for the outer surface and the inner surface of the connecting wall portions 25c and 25d, so that the outer surface and the inner surface do not have to be parallel (for example, refer to FIG. 2C). If all four side walls of the light transmitting body 25 function as a light transmitting wall portion, any of the four side walls can be used as an entrance surface or an exit surface, and therefore the orientation when arranging the gas cell 20A is not limited. It has a high degree of freedom.

The gas cell 20B of the second modified example shown in FIG. 3 includes a pair of flat base bodies 24 having a required shape (for example, a substantially quadrangular shape) and a transparent face plate 26. This is a structure in which the gas filled space 22 is provided by sealing the opening surface of the inner space. As described above, by using the base body 24 made of a structural material such as silicon by a wafer process on only one side and assembling the light transmission body 25 and the face plate 26 to the base body 24, the gas cell 20B as a gas filling container is also provided. Can be produced.

The gas cell 20C of the third modified example shown in FIG. 4 has a structure in which the gas-filled cavity 22 is provided by sealing the inner cavity opening surface of the base body 27 with translucent face plates 26, 26. When the inner cavity of the base body 27 is formed by a semiconductor processing process such as etching, the inner cavity edge 27a may not be uniform (see FIG. 4C). However, as long as the inner edge portion 27a of the base body 27 does not interfere with the optical path OP from the entrance window portion of the one face plate 26 to the exit window portion of the other face plate 26, the gas filled void portion 22 having a slightly distorted shape is formed. It doesn't matter.

FIG. 5(A) shows a gas cell 20A' in which the volume of the gas filled space 22 is increased as compared with the gas cell 20A of the first modified example. In the gas cell 20A', the recessed portion 24a is provided on the inner surface side of each of the base bodies 24', 24' to form the gas filled empty portion 22' with an increased gas filled volume. FIG. 5B shows a gas cell 20B' in which the volume of the gas-filled void 22 is increased as compared with the gas cell 20B of the second modified example. In the gas cell 20B', the recess 24a is provided on the inner surface side of the base body 24', and the recess 26a is also provided on the inner surface side of the face plate 26', thereby forming a gas filled empty portion 22' with an increased gas filled volume. did. FIG. 5C shows a gas cell 20C' in which the volume of the gas-filled space 22 is increased as compared with the gas cell 20C of the third modified example. In the gas cell 20C', a recess 26a is provided on the inner surface side of each face plate 26', 26' to form a gas filled space 22' with an increased gas filled volume.

Next, a specific structure of the quantum optical unit 3A will be described. The supporting means 10A has a structure in which the first tether 12a and the second tether 12b are held by the main frame 11 fixed to an appropriate position (for example, the bottom) of the closed container 2. When the main frame 11 is arranged like four side walls, for example, the protruding ends of the first and second tethers 12a and 12b extending from the respective main frames 11 are inwardly close to each other, and the first and second The heat insulating means 40A can be stably supported on the protruding end sides of the tethers 12a and 12b. For example, the first heat insulator 41 is provided between the first tether 12a and the gas cell 20, and the second heat insulator 42 is provided between the second tether 12b and the gas cell 20.

The first and second heat insulators 41 and 42 are made of a heat insulating material such as a foam material having a low thermal conductivity and formed into, for example, a cylindrical shape. The second tether in which the light emitting element 51 is provided on the side opposite to the heat insulator (the upper surface side in FIG. 1) of the first tether 12a to which the one side of the first heat insulator 41 is fixed and the one side of the second heat insulator 42 is fixed The light receiving element 52 is provided on the side opposite to the heat insulating body 12b (the lower surface side in FIG. 1). According to this structure, the heat from the temperature raising means 30 and the heat from the gas cell 20 whose temperature is controlled at a high temperature are generated by the temperature gradient generated through the first and second heat insulators 41 and 42, and the first and second tethers. It is difficult to transmit to 12a and 12b, and it is possible to prevent the temperature rise of the light emitting element 51 and the light receiving element 52. Therefore, the light emitting element 51 and the light receiving element 12 corresponding to the semiconductor element group can perform temperature management by an original temperature control system different from the temperature management of the gas cell 20.

The temperature control is not limited to the control for controlling both the light emitting element 51 and the light receiving element 52, and only one of the light emitting element 51 and the light receiving element 52 may be temperature controlled by the temperature control means 60, or other semiconductor elements. The temperature management may be performed for Further, the temperature management unit 60 may perform control that intervenes in the operation of the temperature raising unit 30 of the gas cell 20 in order to manage the temperatures of the light emitting element 51 and the light receiving element 52. For example, when the temperature detected by the first and second element temperature detecting means 61, 62 exceeds the upper limit reference temperature defined with reference to the temperature range in which the element can be stably operated, the temperature managing means 60 causes the temperature raising means 30. To stop. In this way, it is possible to prevent the light emitting element 51, the light receiving element 52, or other semiconductor elements from rising to a dangerous temperature and causing abnormal operation or damage.

The above-described heat insulating unit 40A is composed of the first and second heat insulators 41 and 42 made of a heat insulating material having a low thermal conductivity, but is not limited to this. The heat insulating unit 40A′ shown in FIG. 6A has a structure in which a thin annular first ring 43a and a second ring 43b are arranged with a thin plate spacer 44 at an appropriate distance. If this heat insulating means 40A' is used, the cross-sectional area of the heat conduction path interposed between the gas cell 20 and the semiconductor element group is small, and the conduction distance is long, so it is not a material having a thermal conductivity as low as that of the heat insulating material. However, the temperature rise of the semiconductor element group can be suppressed by an appropriate temperature gradient. The heat insulating means 40A″ shown in FIG. 6(B) is a coil body (spiral structure) of the linear body 45 having a relatively small diameter which serves as a heat conduction path. Even when this heat insulating means 40A″ is used, Since the cross-sectional area of the heat conduction path interposed between the gas cell 20 and the semiconductor element group is small and the conduction distance is long, even if the material is not as low in heat conductivity as the heat insulating material, it is possible to use The temperature rise of the semiconductor element group can be suppressed.

In the quantum optical unit 3A in the quantum optical device 1A of the first embodiment described above, the heat insulating means 40A, 40A′, 40A″ for holding the gas cell 20 in a fixed position is in contact with the tether supporting the semiconductor element group. The structure of the heat insulating means is not limited to this.In the quantum optical unit 3B of the quantum optical device 1B according to the second embodiment shown in Fig. 7, the heat insulating means 40B is directly held by the main frame 11 of the supporting means 10B. 7, the same components as those of the quantum optical device 1A of FIG.1 are designated by the same reference numerals and the description thereof will be omitted, and the gas cell 20 and the semiconductor element group by the temperature control means 60 described above will be omitted. A temperature management function may be provided in the quantum optical device 1B.

The heat insulating means 40B is provided with a first heat insulating tether 43a at an appropriate position (upper side in FIG. 7) of the main frame 11 and is appropriately separated from the first heat insulating tether 43a (lower side in FIG. 7). ) Is provided with a second heat insulating tether 43b. Then, the first face plate 23a side of the gas cell 20 is fixed to the first heat insulating tether 43a, and the second face plate 23b side of the gas cell 20 is fixed to the second heat insulating tether 43b. According to this structure, heat from the temperature raising means 30 and the gas cell 20 must be conducted to the first and second tethers 12a and 12b from the first and second heat insulating tethers 43a and 43b through the main frame 11. The temperature of the light emitting element 51 and the light receiving element 52 is not raised. That is, even when the heat insulating means 40B composed of the first and second heat insulating tethers 43a and 43b is provided, it is difficult for the heat insulating means 40B to be transmitted to the first and second tethers 12a and 12b due to the temperature gradient, and thus the light emitting element 51 and the light receiving element 52 of Prevents temperature rise. Therefore, the light emitting element 51 and the light receiving element 12 corresponding to the semiconductor element group can perform temperature management by an original temperature control system different from the temperature management of the gas cell 20.

The quantum optical devices 1A and 1B according to the first and second embodiments described above do not have a function of blocking radiation from the gas cell 20 whose temperature is controlled at a high temperature. That is, the light emitting element 51 arranged so as to face the first face plate 23a of the gas cell 20 is directly heated by the radiation from the first face plate 23a. Similarly, the light receiving element 52 arranged so as to face the second face plate 23b of the gas cell 20 is directly heated by the radiation from the second face plate 23b. Therefore, in the quantum optical unit 3C of the quantum optical device 1C according to the third embodiment shown in FIG. 8, the structure is provided with the first optical path changing tapered surface 71 and the second optical path changing tapered surface 72 that function as a heat shield. In FIG. 8, the same components as those of the quantum optical device 1A of FIG. Further, the temperature control function of the gas cell 20 and the semiconductor element group by the temperature control means 60 described above may be provided in the quantum optical device 1C.

The supporting means 10C of the quantum optics unit 3C includes a separating portion 132 that appropriately separates the semiconductor element group (the light emitting element 51, the light receiving element 52, and the other semiconductor element 53) from the base portion 131 where the second tether 12b is disposed. Occurs. A slanted wall portion 133 is formed so as to narrow the gas cell disposition space from the separation portion 132 to the disposition position of the first tether 12a. Two surfaces of the slanted wall portion 133 that face each other become a first optical path changing taper surface 71 and a second optical path changing taper surface 72, and the first face plate 23a of the gas cell 20 fixed to the first and second tethers 12a and 12b. It faces the second face plate 23b. That is, the first face plate 23a and the second face plate 23b of the gas cell 20 both face the inner surface of the slant wall portion 133 of the main frame 13, and the light emitting element 51 and the light receiving element 52 are the same as the first face plate 23a of the gas cell 20. It does not receive heat from the second face plate 23b.

Further, the first optical path changing taper surface 71 is arranged at an incident angle of about 45° with respect to the first optical path OP1 through which the light emitted from the light emitting element 51 provided in the base portion 131 travels, and the first optical path changing taper is formed. The light reflected by the surface 71 passes through the second optical path OP2 orthogonal to the first optical path OP1. The second optical path OP2 is an optical path that enters the first face plate 23a of the gas cell 20 substantially vertically and emits the second face plate 23b almost vertically. The second optical path changing tapered surface 72 is arranged at an incident angle of about 45° with respect to the second optical path OP2, and the light reflected by the second optical path changing tapered surface 42 is orthogonal to the second optical path OP2 and is transmitted to the base portion 131. The light enters the light-receiving portion of the light-receiving element 52 through the third optical path OP3 that is directed.

That is, the first and second altitude changing taper surfaces 71 and 72 function as a heat shield that prevents the light emitting element 51 and the light receiving element 52 from rising in temperature due to the radiation from the gas cell 5, and the light emitting element 51→gas cell. 20→The light path of the light receiving element 52 is not obstructed.

In the gas cell 20 maintained at a high temperature, radiant heat is not emitted only from the incident surface of the first face plate 23a and the output face of the second face plate 23b, and radiation is also generated from the side faces. However, the semiconductor element group provided in the base portion 131 has a relatively high radiant heat received from the side surface of the gas cell 5 and the like, which does not hinder the temperature management by the original temperature control system, but has a higher heat shield function. You may allow it. Therefore, in the quantum optical unit 3D of the quantum optical device 1D according to the fourth embodiment shown in FIG. 9, the heat shield 73 functioning as the second heat shield is provided. 9, the same components as those of the quantum optical device 1C of FIG. 8 are designated by the same reference numerals, and the description thereof will be omitted. Further, the temperature control function of the gas cell 20 and the semiconductor element group by the temperature control means 60 described above may be provided in the quantum optical device 1C.

The heat shield 73 of the quantum optical unit 3D is a plate-like member arranged so as to spatially partition between the second tether 12b to which the gas cell 20 is fixed and the semiconductor element group arranged in the base 131. .. The heat shield 73 is provided with at least a first through hole 73a for not blocking the first optical path OP1 and a second through hole 73b for not blocking the third optical path OP3. As the heat shield 73, a material that does not heat itself by reflecting electromagnetic waves, such as a white ceramic material, can be used. Alternatively, the heat shield 73 may be formed by sticking a material having a high electromagnetic wave absorption rate, such as an aluminum foil, on the side of the heat insulating plate on which the second tether 12b is disposed. In this case, since the aluminum foil itself is heated by the radiation from the gas cell 20, it is desirable to provide a means for releasing the heat to the surroundings.

Although the quantum optical device according to the present invention has been described above based on the embodiments, the present invention is not limited to these embodiments and can be realized without changing the configuration described in the claims. It covers all quantum optical devices as a scope of rights.

1A Quantum optical device (first embodiment)
2 Airtight container 10A Supporting means 20 Gas cell 30 Heater 40A Heat insulating means 51 Light emitting element 52 Light receiving element

Claims (6)

A light emitting element that emits excitation light of a plurality of frequencies in the absorption wavelength band of the alkali metal element,
A small gas-filled container in which an alkali metal element and a buffer gas are enclosed in a fine inner space created by a wafer process, which is arranged at a position to receive excitation light from the light emitting element from a transparent window portion,
A temperature raising means for heating the gas filling container to a high temperature so that the gas component sealed in the gas filling container maintains a gas state,
A light-receiving element that is arranged at a position for receiving light that has passed through the gas filling container and that detects the light intensity of the received light,
CPT resonance trapping for matching the frequency difference of the excitation light output from the light emitting element with the frequency difference between the base ranks in the alkali metal element so as to generate the CPT resonance that maximizes the light intensity detected by the light receiving element. One or more semiconductor elements responsible for performing the function,
At least a heat insulating means interposed between the light emitting element and the gas filling container, and between the light receiving element and the gas filling container,
A quantum optical device comprising: The quantum optical device according to claim 1, wherein the heat insulating unit is a heat insulating material having a low thermal conductivity. The quantum optical device according to claim 1, wherein the heat insulating unit reduces the cross-sectional area of the heat conduction path and lengthens the distance of the heat conduction path. The heat shield means for suppressing the radiation from the temperature raising means of the gas filling device acting on the light emitting element, the light receiving element and the semiconductor element is provided. The quantum optical device according to the item. The quantum optical device according to claim 1, wherein at least one of the light emitting element, the light receiving element, and the semiconductor element implements temperature management by a unique temperature control system. At least one of the light emitting element, the light receiving element, and the semiconductor element is provided with an element temperature detecting means for detecting the temperature of the element,
When the detected temperature exceeds the upper limit reference temperature determined by obtaining the temperature detected by the element temperature detection means and the temperature range in which the element can be stably operated as a reference, a temperature management means for stopping the temperature raising means is provided. The quantum optical device according to claim 1, further comprising: a quantum optical device.

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