JPH05235759A - Rubidium atom oscillator - Google Patents

Abstract

PURPOSE:To make a cavity of a microwave unit of the rubidium atom oscillator small, to reduce the cost and to make the Q stable. CONSTITUTION:A spherical or semi-spherical rubidium gas cell 7 having one projection 7a and a light receiving element 6 are packed in a cylindrical cavity section 3. A tuning projection rod 1 is fixed to a position at nearly 1/3 of the cavity length while avoiding the rubidium gas cell 7 and a tuning projection rod 5 is formed such that its insertion depth is adjustable. Thus, the resonance frequency of the cavity 3 is easily adjusted so as to be resonated with a micro wave inputted from a microwave entry section 4. As a result, the simple semi- spherical rubidium gas cell is realized. Furthermore, the projection 7a of the rubidium gas cell is cooled by an atmospheric air coming from a vent hole 8 of the cavity section to prevent diffusion of a rubidium metal and a high Q is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atomic oscillator, and more particularly to a rubidium atomic oscillator using an optical pumping method.

[0002]

2. Description of the Related Art A rubidium atomic oscillator requires a cavity for utilizing atomic resonance, and the cavity must be capable of adjusting the resonance frequency due to a shape error of a rubidium gas cell inserted therein. is there. When trying to miniaturize the cavity, the cavity is filled with the rubidium gas cell so that for the frequency adjustment, one recess is set on the cell wall surface at right angles to the center axis of the rubidium gas cell. In addition, a method is adopted in which a projecting portion that penetrates the wall surface of the cavity is projectably projectable. In addition, since the cavity around the rubidium gas cell has a sealed structure, the temperature of the rubidium gas cell is uniformly warmed, and rubidium metal easily diffuses into the rubidium gas cell.

[0003]

In the above-mentioned conventional technique, it is difficult to manufacture the rubidium gas cell because it is necessary to provide a concave portion on the circumferential surface of the rubidium gas cell, which is expensive. In addition, since it is structurally difficult to reduce the inner thickness of the glass, there is a large amount of light loss due to the glass on the light passage surface of the rubidium gas cell, and there is a drawback that the signal strength is reduced.

Further, since rubidium metal easily diffuses into the rubidium gas cell, there is a drawback that the microwave level for the cavity is easily lowered when it is used for a long period of time.

The present invention has been made in view of the above-mentioned conventional circumstances, and therefore an object of the present invention is to provide a novel rubidium atomic oscillator capable of solving the above-mentioned drawbacks inherent in the conventional technology. To do.

[0006]

In order to achieve the above object, a rubidium atomic oscillator according to the present invention has a spherical or hemispherical rubidium gas cell having protrusions fixed in a cavity and penetrating a wall surface of the cavity. One of the two protrusions, the first or the second, can be projected and retracted, and a hole is further formed in the bottom of the cavity so that the protrusion of the rubidium gas cell is exposed to the outside air to be cooled.
It is characterized by miniaturizing the cavity and preventing the diffusion of rubidium metal in the rubidium gas cell.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the accompanying drawings with reference to the accompanying drawings.

1 (a) and 1 (b) are front views of a cavity showing an embodiment of the present invention and AA 'in FIG. 1 (a).
It is sectional drawing cut | disconnected along the line and seen in the direction of the arrow.

Referring to FIGS. 1 (a) and 1 (b), a spherical cavity 3 having a projection 7a and a spherical or hemispherical rubidium gas cell 7 and a light receiving element 6 are filled in a cavity 3 having a cylindrical shape. The tuning protrusion rod 1 is fixed at a position of about 1/3 of the cavity length while avoiding the rubidium gas cell 7, and the tuning protrusion rod 5 can change the insertion depth. By doing so, the resonance frequency of the cavity 3 can be easily adjusted so as to resonate with the microwave input from the microwave introduction unit 4. As a result, microwaves of sufficient intensity are supplied to the rubidium gas cell 7, so that the light incident from the light entrance hole 2 is absorbed by the rubidium gas cell 7 and then the light receiving element 6
Then, the signal necessary for operating as an atomic oscillator can be obtained.

Further, outside air enters from the vent holes 8 at the bottom of the cavity, and the projections 7a of the rubidium gas cell 7 are cooled, so that the rubidium metal in the rubidium gas cell is prevented from diffusing and a stable Q is obtained.

As described above, according to the present invention, the rubidium gas cell is fixed to the cavity 3 as a spherical or hemispherical structure having a projection, and the protrusion penetrating the wall surface of the cavity 3 is arranged with respect to the central axis of the rubidium gas cell 7. By arranging two symmetrically and fixing one of them and allowing the other to project and retract, the adjustment becomes easy, and further, the protruding rod does not project into the light incident hole, and the decrease in signal strength is prevented. You can Further, the rubidium metal in the rubidium gas cell is prevented from diffusing by being cooled by the outside air entering from the vent hole 8 provided at the bottom of the cavity, a high Q is obtained, and a smaller, high-performance, low-cost rubidium atomic oscillator is obtained. There is an effect that can be provided.

[0012]

As described above, according to the present invention,
The rubidium gas cell is fixed to the cavity as a spherical or hemispherical structure having one projection, and two protrusions penetrating the wall surface of the cavity are symmetrically provided with respect to the central axis of the rubidium gas cell, and one of them is fixed, and the other is fixed. By making the structure capable of projecting and retracting, the adjustment becomes easy, and further, the protruding rod does not project into the light incident hole, and it is possible to prevent a decrease in signal intensity. Also, it is possible to prevent the diffusion of rubidium metal and to obtain a high Q value. As a result, there is an effect that a small-sized, high-performance and low-cost rubidium atomic oscillator can be supplied.

[Brief description of drawings]

FIG. 1A is a front view of a cavity portion showing an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line AA ′ of FIG. Is.

[Explanation of symbols]

 1 ... Tuning protrusion rod 2 ... Light incident hole 3 ... Cavity 4 ... Microwave introducing part 5 ... Tuning protrusion rod 6 ... Light receiving element 7 ... Rubidium gas cell 8 ... Vent hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Kudo No.2 Raijin, Yoshioka, Yamato-cho, Kurokawa-gun, Miyagi Miyagi NEC Corporation

Claims (2)

[Claims] 1. A rubidium atomic oscillator including a rubidium lamp portion and an optical microwave resonance portion including a cavity portion,
In particular, in the cavity portion, a spherical or hemispherical rubidium gas cell provided in the cavity and having one protrusion, a first protruding portion fixed through the side surface of the cavity, and the first protrusion And a second protrusion that is symmetrically set with respect to the central axis of the rubidium gas cell and that can project and retract through the side surface of the cavity.
A rubidium atomic oscillator, comprising: a ventilation hole formed on an outer wall of the cavity. 2. The rubidium atomic oscillator according to claim 1, further comprising the vent hole formed in the vicinity of the protrusion of the rubidium gas cell.