CN113484921B - Four-frequency double-Raman laser system and cold atom horizontal gravity gradient measurement method - Google Patents
Four-frequency double-Raman laser system and cold atom horizontal gravity gradient measurement method Download PDFInfo
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Abstract
The invention relates to a four-frequency double-Raman laser system and a cold atom horizontal gravity gradient measurement methodf 1 Andf 2 two laser beams; at a frequency off 1 Is modulated to generate a laser beam comprisingf 1 Andf 3 laser light of two frequency components; at a frequency off 2 Is modulated to generate a laser beam comprisingf 2 Andf 4 laser light of two frequency components; frequency off 1 、f 2 、f 3 、f 4 Satisfies the following conditions:f 1 ≠f 2 ，f 3 ‑f 1 ≠f 4 ‑f 2 ，f 4 ‑f 1 =f 3 ‑f 2 (ii) a At a frequency off 1 Andf 4 the laser of (a) constitutes a first group of Raman lasers at a frequency off 2 Andf 3 the effective wave vector directions of the two groups of Raman lasers are opposite, and the laser pulse sequences of pi/2-pi/2 act on atoms simultaneously. The invention solves the problem of multiple interference paths of the three-frequency double-Raman technology and effectively improves the measurement precision.
Description
Technical Field
The invention relates to the field of cold atom interference precision measurement, in particular to a four-frequency double-Raman laser system and a cold atom horizontal gravity gradient measurement method.
Background
The cold atom interference technology is widely used for measuring inertia quantities such as gravitational acceleration, gravity gradient, earth rotation and the like and carrying out basic physical researches such as equivalent principle inspection, gravitational wave detection and the like. The conventional Atomic interferometer is based on two-photon stimulated Raman transitions, and the working principle is described in the literature (Atomic interferometry used stimulated Raman transitions, m. Kasevich et al, phys. rev. lett. volume 67, page 181, 1991), and can be briefly described as follows: the cold atomic group generates the beam splitting, reflecting and combining processes similar to an optical interferometer under the action of the pi/2-pi/2 Raman laser pulse sequence, and finally the distribution probability of atoms in two end state paths and the relative phase of Raman laser form a sine relationship. This type of atomic interferometer is sensitive to optical frequency shift noise of raman laser light as well as magnetic field noise. For example, in an atomic gravity gradiometer system, the absolute measurement accuracy of the gravity gradient of 10E requires that the magnetic field gradient of the interference region is less than 100 μ Gs/cm. Therefore, the magnetic field noise limits the further improvement of the measurement accuracy of the atomic gravity gradiometer, and causes the environmental adaptability of the atomic gravity gradiometer to be poor. In recent years, the three-frequency double-Raman interference technology is adopted abroad to realize the atomic absolute gravimeter for pure foreign state interference measurement, the technology greatly reduces the sensitivity of the atomic interferometer to Raman laser optical frequency shift noise and magnetic field noise, can also increase the scale factor of measurement, and is beneficial to improving the measurement precision and the environmental adaptability of the atomic interferometer.
In a cold atom horizontal gravity gradiometer system, atoms are thrown along the vertical direction, Raman light is transmitted along the horizontal direction, the transverse diffusion speed of the atoms is too low, the probability of diffusion towards the two directions is consistent, no Doppler effect is caused, homodromous Raman transition and opposite Raman transition exist simultaneously by adopting a tri-frequency dual-Raman technology, multiple interference paths are caused, and interference measurement cannot be formed.
Disclosure of Invention
The invention provides a four-frequency double-Raman laser system and a cold atom horizontal gravity gradient measurement method aiming at the technical problems in the prior art, and solves the problems that multiple interference paths exist in a cold atom horizontal gravity gradient instrument system and interference measurement cannot be formed.
The technical scheme for solving the technical problems is as follows:
according to a first aspect of the present invention, a four-frequency dual-raman laser system is provided, including a laser generating unit, a laser splitting unit, a first laser frequency shifting unit, a second laser frequency shifting unit, a first electro-optical modulation unit and a second electro-optical modulation unit, where an output of the laser generating unit is connected to an input of the laser splitting unit, the laser splitting unit is provided with two output ends, one output end of the laser splitting unit, the first laser frequency shifting unit and the first electro-optical modulation unit are sequentially connected, and the other output end of the laser splitting unit, the second laser frequency shifting unit and the second electro-optical modulation unit are sequentially connected;
one beam of laser output by the laser generating unit passes through the laser splitting unit, the first laser frequency shift unit and the second laser frequency shift unit and then is divided into a beam of laser with a frequency off 1 Andf 2 two laser beams;
at a frequency off 1 The laser is modulated by the first electro-optical modulation unit to generate a laser beamf 1 Andf 3 outputting the first Raman laser with two frequency components;
at a frequency off 2 The laser is modulated by the second electro-optical modulation unit to generate a laser beamf 2 Andf 4 outputting the second Raman laser with two frequency components;
frequency off 1 、f 2 、f 3 、f 4 Satisfies the following conditions:f 1 ≠f 2 ，f 3 -f 1 ≠f 4 -f 2 ，f 4 -f 1 =f 3 -f 2 ；
at a frequency off 1 With a laser and a frequency off 4 The laser of (a) constitutes a first group of Raman lasers at a frequency off 2 With a laser and a frequency off 3 The effective wave vector directions of the two groups of Raman lasers are opposite, and the laser pulse sequences of pi/2-pi/2 act on atoms simultaneously.
On the basis of the technical scheme, the invention can be further improved as follows.
Furthermore, the laser system also comprises a radio frequency generation unit, wherein the radio frequency generation unit is provided with two output ends, one output end of the radio frequency generation unit is connected with the drive end of the first laser frequency shift unit, and the other output end of the radio frequency generation unit is connected with the drive end of the second laser frequency shift unit; the radio frequency generating unit is used for respectively driving the first laser frequency shifting unit and the second laser frequency shifting unit.
Further, the radio frequency generating unit comprises a first radio frequency signal source, a second radio frequency signal source, a first radio frequency amplifying module, a second radio frequency amplifying module and a radio frequency switching module; the radio frequency switching module is provided with two channels, a first channel of the first radio frequency signal source, the first radio frequency amplification module and the radio frequency switching module is sequentially connected in series and then connected with the driving end of the first laser frequency shift unit, and a second channel of the second radio frequency signal source, the second radio frequency amplification module and the radio frequency switching module is sequentially connected in series and then connected with the driving end of the second laser frequency shift unit;
the first radio frequency signal source and the second radio frequency signal source respectively generate two paths of radio frequency signals with different frequencies, the radio frequency signals are amplified by the first radio frequency amplification module and the second radio frequency amplification module respectively, and the two paths of radio frequency signals are output by the two channels of the radio frequency switching module respectively and used for driving the first laser frequency shift unit and the second laser frequency shift unit respectively.
Further, the radio frequency switching module comprises a first radio frequency input channel, a second radio frequency input channel, a first radio frequency output channel and a second radio frequency output channel; the radio frequency switching module can realize the following two signal output modes:
mode A: the output signal of the first radio frequency output channel is the same as the input signal of the first radio frequency input channel, and the output signal of the second radio frequency output channel is the same as the input signal of the second radio frequency input channel;
and (3) mode B: the output signal of the first radio frequency output channel is the same as the input signal of the second radio frequency input channel, and the output signal of the second radio frequency output channel is the same as the input signal of the first radio frequency input channel;
the switching between mode a and mode B is controlled by the high and low levels of the digital signal.
Furthermore, the laser system also comprises a microwave generating unit, wherein the microwave generating unit is provided with two output ends, one output end of the microwave generating unit is connected with the driving end of the first electro-optical modulation unit, and the other output end of the microwave generating unit is connected with the driving end of the second electro-optical modulation unit; the microwave generating unit is used for respectively driving the first electro-optical modulating unit and the second electro-optical modulating unit.
Further, the microwave generating unit comprises a first microwave signal source, a second microwave signal source, a first microwave amplification module, a second microwave amplification module and a microwave switching module, the microwave switching module is provided with two channels, a first channel of the first microwave signal source, the first microwave amplification module and the microwave switching module is connected in series in sequence and then connected with the driving end of the first electro-optical modulation unit, and a second channel of the second microwave signal source, the second microwave amplification module and the microwave switching module is connected in series in sequence and then connected with the driving end of the second electro-optical modulation unit;
the first microwave signal source and the second microwave signal source respectively generate two paths of microwave signals with different frequencies, the two paths of microwave signals are respectively amplified by the first microwave amplification module and the second microwave amplification module and respectively output by the two channels of the microwave switching module, and the two paths of microwave signals are used for respectively driving the first electro-optical modulation unit and the second electro-optical modulation unit.
Further, the microwave switching module comprises a first microwave input channel, a second microwave input channel, a first microwave output channel and a second microwave output channel; the microwave switching module can realize the following two signal output modes:
and mode C: the output signal of the first microwave output channel is the same as the input signal of the first microwave input channel, and the output signal of the second microwave output channel is the same as the input signal of the second microwave input channel;
mode D: the output signal of the first microwave output channel is the same as the input signal of the second microwave input channel, and the output signal of the second microwave output channel is the same as the input signal of the first microwave input channel;
the switching between mode C and mode D is controlled by the high and low levels of the digital signal.
Further, the laser system further comprises a first raman laser output unit and a second raman laser output unit, wherein the input of the first raman laser output unit is connected with the output of the first electro-optical modulation unit, and the output of the first raman laser output unit comprisesf 1 Andf 3 a first Raman laser of two frequency components; the input of the second Raman laser output unit is connected with the output of the second electro-optical modulation unit, and the output of the second Raman laser output unit comprisesf 2 Andf 4 a second Raman laser of two frequency components.
According to a second aspect of the present invention, based on the above four-frequency dual raman laser system, the present invention further provides a cold atom horizontal gravity gradient measurement method, including the following steps:
s1, system parameters are set, so that the frequency of the four output lasers is enabled to bef 1 、f 2 、f 3 Andf 4 satisfies the following conditions:f 1 ≠f 2 ，f 3 -f 1 ≠f 4 - f 2 ，f 4 -f 1 =f 3 -f 2 ；
s2, the output frequency component of the control system isf 1 Andf 3 the first Raman laser has a frequency component off 2 Andf 4 of a second Raman laser of (1), wherein the frequency isf 1 Andf 4 the two lasers form a first group of Raman lasers with the frequency off 2 Andf 3 the two lasers form a second group of Raman lasers, and the effective wave vector directions of the first group of Raman lasers and the second group of Raman lasers are opposite;
s3, the first group of Raman laser and the second group of Raman laser respectively act on atoms at the same time by using the Raman laser pulse sequence of pi/2-pi/2 to generate atom interference signals.
Further, in step S3,
1.1 when the method is applied to an upper-throwing type atomic interferometer, the method has the following two working modes:
1.1.1 when the 1 st Raman laser pulse acts, the radio frequency switching module works in a mode A, and the microwave switching module works in a mode C; when the 2 nd Raman laser pulse acts, the radio frequency switching module works in a mode B, and the microwave switching module works in a mode D; when the 3 rd Raman laser pulse acts, the radio frequency switching module works in a mode A, and the microwave switching module works in a mode C;
1.1.2 when the 1 st Raman laser pulse acts, the radio frequency switching module works in a mode B, and the microwave switching module works in a mode D; when the 2 nd Raman laser pulse acts, the radio frequency switching module works in a mode A, and the microwave switching module works in a mode C; when the 3 rd Raman laser pulse acts, the radio frequency switching module works in a mode B, and the microwave switching module works in a mode D;
1.2 when the method is applied to a falling-type atomic interferometer, the method has the following two working modes:
1.2.1 when the whole pi/2-pi/2 Raman laser pulse sequence acts, the radio frequency switching module works in a mode A, and the microwave switching module works in a mode C;
1.2.2 when the whole pi/2-pi/2 Raman laser pulse sequence acts, the radio frequency switching module works in a mode B, and the microwave switching module works in a mode D.
The invention has the beneficial effects that:
1. the four-frequency double-Raman laser system is realized by using the two electro-optical modulators, and the problem of multiple interference paths when a three-frequency double-Raman technology is used for a cold atom horizontal gravity gradiometer system can be solved;
2. the invention realizes double Raman transition, compared with the traditional single Raman transition system, the measurement scale factor is doubled, and the atoms on the two interference paths are in the same internal state, so that the measurement result is less sensitive to the environmental magnetic field noise, and the measurement precision can be effectively improved;
3. the invention can realize the rapid switching of the effective wave vector direction of the Raman laser.
Drawings
FIG. 1 is a block diagram of the overall system of the present invention;
FIG. 2 is a block diagram of the RF generating unit according to the present invention;
FIG. 3 is a block diagram of the microwave generating unit according to the present invention;
FIG. 4 (a) is a schematic diagram of the setting of the frequency of the four-frequency double Raman laser according to the present invention, and FIG. 4 (b) is a schematic diagram of the setting of the propagation direction of the four-frequency double Raman laser according to the present invention;
fig. 5 (a) is a working principle diagram of the dual raman atomic interferometer of the present invention, and fig. 5 (b) is a working principle diagram of the single raman atomic interferometer of the present invention;
FIG. 6 shows the variation of laser frequency values when the present invention uses a pi/2-pi/2 Raman laser pulse sequence to perform coherent operations on cold atoms.
In the drawings, the components represented by the respective reference numerals are listed below:
1. the laser Raman laser comprises a laser generating unit, 2, a laser beam splitting unit, 3, a first laser frequency shifting unit, 4, a second laser frequency shifting unit, 5, a first electro-optical modulating unit, 6, a second electro-optical modulating unit, 7, a radio frequency generating unit, 701, a first radio frequency signal source, 702, a second radio frequency signal source, 703, a first radio frequency amplifying module, 704, a second radio frequency amplifying module, 705, a radio frequency switching module, 8, a microwave generating unit, 801, a first microwave signal source, 802, a second microwave signal source, 803, a first microwave amplifying module, 804, a second microwave amplifying module, 805, a microwave switching module, 9, a first Raman laser output unit, 10 and a second Raman laser output unit.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.
Fig. 1 is a block diagram of a system of a four-frequency dual raman laser system according to the present invention. The four-frequency double-Raman laser system comprises a laser generating unit 1, a laser splitting unit 2, a first laser frequency shifting unit 3, a second laser frequency shifting unit 4, a first electro-optical modulation unit 5, a second electro-optical modulation unit 6, a radio frequency generating unit 7, a microwave generating unit 8, a first Raman laser output unit 9 and a second Raman laser output unit 10. The output of the laser generation unit 1 is connected with the input of the laser splitting unit 2, the laser splitting unit 2 is provided with two output ends, one output end of the laser splitting unit 2, the first laser frequency shift unit 3, the first electro-optic modulation unit 5 and the first Raman laser output unit 9 are sequentially connected, and the other output end of the laser splitting unit 2, the second laser frequency shift unit 4, the second electro-optic modulation unit 6 and the second Raman laser output unit 10 are sequentially connected. The radio frequency generation unit 7 is provided with two output ends, one output end of the radio frequency generation unit 7 is connected with the driving end of the first laser frequency shift unit 3, and the other output end of the radio frequency generation unit 7 is connected with the driving end of the second laser frequency shift unit 4; the radio frequency generating unit 7 is used for respectively driving the first laser frequency shifting unit 3 and the second laser frequency shifting unit 4. The microwave generating unit 8 is provided with two output ends, one output end of the microwave generating unit 8 is connected with the driving end of the first electro-optical modulating unit 5, and the other output end of the microwave generating unit 8 is connected with the driving end of the second electro-optical modulating unit 6; the microwave generating unit 8 is used for driving the first electro-optical modulating unit 5 and the second electro-optical modulating unit 6 respectively.
One laser beam output by the laser generating unit 1 is excitedThe light splitting unit 2 splits the laser into two laser beams with the same frequency, and the two laser beams are converted into two laser beams with the same frequency after passing through the first laser frequency shift unit 3 and the second laser frequency shift unit 4 respectivelyf 1 Andf 2 two laser beams.
At a frequency off 1 Is modulated by a first electro-optical modulation unit 5 to generate a laser beamf 1 Andf 3 the first raman laser light of the two frequency components is output through the first raman laser output unit 9.
At a frequency off 2 Is modulated by a second electro-optical modulation unit 6 to generate a laser beam containingf 2 Andf 4 the second raman laser light of the two frequency components is output through the second raman laser output unit 10.
Frequency off 1 、f 2 、f 3 、f 4 Satisfies the following conditions:f 1 ≠f 2 ，f 3 -f 1 ≠f 4 -f 2 ，f 4 -f 1 =f 3 -f 2 。
when cold atom horizontal gravity gradient measurement is carried out, the frequency isf 1 With a laser and a frequency off 4 The laser of (a) constitutes a first group of Raman lasers at a frequency off 2 With a laser and a frequency off 3 The effective wave vector directions of the two groups of Raman lasers are opposite, and the laser pulse sequences of pi/2-pi/2 act on atoms simultaneously.
It can be understood that the laser generating unit 1 generates single-frequency laser light whose power, frequency and polarization meet the requirements; the laser light splitting unit 2 divides the laser light generated by the laser generating unit 1 into two paths, the two paths of laser light have the same frequency, and the power ratio can be adjusted; the first laser frequency shift unit 3 and the second laser frequency shift unit 4 respectively change the laser beam splitting unit2, the frequency of the two paths of laser output; the first electro-optical modulation unit 5 and the second electro-optical modulation unit 6 respectively perform electro-optical phase modulation on the laser output by the first laser frequency shift unit 3 and the laser output by the second laser frequency shift unit 4, so that the output laser comprises a carrier and a sideband; the radio frequency generating unit 7 is used for generating two paths of radio frequency signals with power, frequency and phase meeting requirements and driving core devices of the first laser frequency shifting unit 3 and the second laser frequency shifting unit 4, such as an acousto-optic modulator; the microwave generating unit 8 is configured to generate two paths of microwave signals with power, frequency, and phase satisfying requirements, and drive core devices of the first electro-optical modulating unit 5 and the second electro-optical modulating unit 6, such as an electro-optical phase modulator. Finally, the first Raman laser output unit 9 outputs an output includingf 1 Andf 3 the first Raman laser of two frequency components and the second Raman laser output unit 10 output a first Raman laser beam containingf 2 Andf 4 a second Raman laser of two frequency components.
In a possible embodiment, as shown in fig. 2, the rf generating unit 7 includes a first rf signal source 701, a second rf signal source 702, a first rf amplifying module 703, a second rf amplifying module 704, and an rf switching module 705, and its structure is: the radio frequency switching module 705 is provided with two channels, a first channel of the first radio frequency signal source 701, the first radio frequency amplification module 703 and the radio frequency switching module 705 is sequentially connected in series and then connected to the driving end of the first laser frequency shift unit 3, and a second channel of the second radio frequency signal source 702, the second radio frequency amplification module 704 and the radio frequency switching module 705 is sequentially connected in series and then connected to the driving end of the second laser frequency shift unit 4. The first radio frequency signal source 701 and the second radio frequency signal source 702 generate one path of radio frequency signal respectively, and the frequencies of the two paths of radio frequency signals are different. The two paths of rf signals are amplified by the first rf amplifying module 703 and the second rf amplifying module 704, and then output two paths of amplified rf signals through two channels of the rf switching module 705, where the two paths of amplified rf signals are used to drive the first laser frequency shifting unit 3 and the second laser frequency shifting unit 4, respectively.
Further, the rf switch module 705 includes a first rf input channel, a second rf input channel, a first rf output channel, and a second rf output channel. The rf switch module 705 can implement the following two signal output modes:
mode A: the output signal of the first radio frequency output channel is the same as the input signal of the first radio frequency input channel, and the output signal of the second radio frequency output channel is the same as the input signal of the second radio frequency input channel;
and (3) mode B: the output signal of the first radio frequency output channel is the same as the input signal of the second radio frequency input channel, and the output signal of the second radio frequency output channel is the same as the input signal of the first radio frequency input channel.
The switching between mode a and mode B is controlled by the high and low levels of the digital signal.
In a possible embodiment, as shown in fig. 3, the microwave generating unit 8 includes a first microwave signal source 801, a second microwave signal source 802, a first microwave amplifying module 803, a second microwave amplifying module 804 and a microwave switching module 805, and has a structure that: the microwave switching module 805 is provided with two channels, a first channel of the first microwave signal source 801, the first microwave amplification module 803 and the microwave switching module 805 is sequentially connected in series and then connected to the driving end of the first electro-optical modulation unit 5, and a second channel of the second microwave signal source 802, the second microwave amplification module 804 and the microwave switching module 805 is sequentially connected in series and then connected to the driving end of the second electro-optical modulation unit 6.
The first microwave signal source 801 and the second microwave signal source 802 generate one path of microwave signal respectively, and the two paths of microwave signal have different frequencies. The two paths of microwave signals are respectively amplified by the first microwave amplification module 803 and the second microwave amplification module 804, and respectively output two paths of amplified microwave signals through two channels of the microwave switching module 805, and the two paths of amplified microwave signals are used for respectively driving the first electro-optical modulation unit 5 and the second electro-optical modulation unit 6.
Further, the microwave switching module 805 includes a first microwave input channel, a second microwave input channel, a first microwave output channel, and a second microwave output channel. The microwave switching module 805 can implement the following two signal output modes:
and mode C: the output signal of the first microwave output channel is the same as the input signal of the first microwave input channel, and the output signal of the second microwave output channel is the same as the input signal of the second microwave input channel;
mode D: the output signal of the first microwave output channel is the same as the input signal of the second microwave input channel, and the output signal of the second microwave output channel is the same as the input signal of the first microwave input channel.
The switching between mode C and mode D is controlled by the high and low levels of the digital signal.
The working principle of the laser system is as follows:
as shown in fig. 4 (a) and 4 (b), the frequencies aref 1 、f 2 、f 3 、f 4 The four laser beams act on atoms simultaneously, wherein the frequency isf 1 Andf 3 the first Raman laser propagates from left to right at a frequency off 2 Andf 4 is propagated from right to left, andf 1 andf 2 the difference in the values of,f 3 Andf 4 the difference in values of (a) is small. Suppose thatf 1 Andf 2 is different from andf 3 andf 4 all are different from each otherδBy setting a specific frequency relationship such that the frequency isf 1 、f 2 、f 3 、f 4 The following relationship is satisfied:
wherein the content of the first and second substances,Δωis the difference in frequency between atomic energy levels. Under the above conditions, the frequency isf 1 Andf 4 the two lasers form a first group of Raman lasers with effective wave vectors towards left and the frequency of the first group of Raman lasersf 2 Andf 3 the two lasers form a second group of Raman lasers with the effective wave vector towards the right, and the two groups of Raman lasers are combined to simultaneously act on atoms to generate double Raman transitions. At the same time, due to the differenceδAt a frequency off 1 Andf 2 laser light and frequency off 3 Andf 4 cannot constitute a homotropic raman transition.
The working principle of the four-frequency double-Raman atomic interferometer is shown in (a) in FIG. 5, four beams of laser satisfying the relationship shown in the formula are used for forming Raman laser, and pi/2-pi/2 Raman laser pulse sequence is used for carrying out coherent operation on cold atoms to form an atomic interference loop. The atoms on the two interference paths are at the same internal energy level and the atoms on the two paths have a difference of 4 photon back-recoil momentum after a single raman laser pulse.
The working principle of the conventional single-Raman atomic interferometer is shown in (b) of FIG. 5, and the frequencies are respectivelyf 1 Andf 2 the two beams of coherent laser form Raman laser, the cold atoms are sequentially subjected to coherent operation by utilizing a pi/2-pi/2 Raman laser pulse sequence, the atoms on the two interference paths are in different internal energy levels, and the atoms on the two paths have the difference of two photon recoil momentum after the single Raman laser pulse acts on the cold atoms.
Therefore, in summary, the four-frequency double-raman technique can generate photon back-reflection momentum twice larger than that of the traditional single-raman technique, namely, the measurement scale factor is doubled, and meanwhile, the special raman laser frequency setting mode of the four-frequency double-raman technique can avoid the homodromous interference process generated in the horizontal gravity gradiometer system.
Based on the four-frequency double-Raman laser system provided by the invention, the invention also provides a cold atom horizontal gravity gradient measurement method applying the laser system to a cold atom interferometer. The method comprises the following steps:
s1, is providedSetting system parameters, e.g. setting the frequency of the RF signal output by RF generating unit 7 and the frequency of the microwave signal output by microwave generating unit 8, so as to output the frequency of four lasersf 1 、f 2 、f 3 Andf 4 satisfies the following conditions:f 1 ≠f 2 ，f 3 -f 1 ≠f 4 -f 2 ，f 4 - f 1 =f 3 -f 2 ；
s2, controlling the working modes of the radio frequency generating unit 7 and the microwave generating unit 8, driving the first laser frequency shifting unit 3, the second laser frequency shifting unit 4, the first electro-optical modulating unit 5 and the second electro-optical modulating unit 6 to work, and enabling the output frequency component of the laser system to be the samef 1 Andf 3 the first Raman laser has a frequency component off 2 Andf 4 of a second Raman laser of (1), wherein the frequency isf 1 Andf 4 the two lasers form a first group of Raman lasers with the frequency off 2 Andf 3 the two lasers form a second group of Raman lasers, and the effective wave vector directions of the first group of Raman lasers and the second group of Raman lasers are opposite;
s3, the first group of Raman laser and the second group of Raman laser respectively act on atoms at the same time by using the Raman laser pulse sequence of pi/2-pi/2 to generate atom interference signals.
Further, in step S3, since the atom interferometers are divided into the upper-polished atom interferometer and the lower-polished atom interferometer, the present laser system is applicable to both types of atom interferometers.
1.1 when the method is applied to an upper-throwing type atomic interferometer, the method has the following two working modes:
1.1.1 when the 1 st raman laser pulse (i.e., the first pi/2 raman laser pulse) is active, the rf switch 705 operates in mode a and the microwave switch 805 operates in mode C; when the 2 nd raman laser pulse (i.e., the pi raman laser pulse) acts, the radio frequency switching module 705 operates in the mode B, and the microwave switching module 805 operates in the mode D; when the 3 rd raman laser pulse (i.e., the second pi/2 raman laser pulse) is active, the rf switch 705 operates in mode a and the microwave switch 805 operates in mode C;
1.1.2 when the 1 st raman laser pulse (i.e., the first pi/2 raman laser pulse) is active, the rf switch 705 operates in mode B and the microwave switch 805 operates in mode D; when the 2 nd raman laser pulse (i.e., the pi raman laser pulse) acts, the radio frequency switching module 705 operates in the mode a, and the microwave switching module 805 operates in the mode C; when the 3 rd raman laser pulse (i.e., the second pi/2 raman laser pulse) is active, the rf switch 705 operates in mode B and the microwave switch 805 operates in mode D.
1.2 when the method is applied to a falling-type atomic interferometer, the method has the following two working modes:
1.2.1 when the whole pi/2-pi/2 Raman laser pulse sequence acts, the radio frequency switching module 705 works in the mode A, and the microwave switching module 805 works in the mode C;
1.2.2 when the entire pi/2-pi/2 raman laser pulse sequence is active, the rf switch 705 operates in mode B and the microwave switch 805 operates in mode D.
The operation mode of the rf switch module 705 and the operation mode of the microwave switch module 805 can be flexibly controlled by the high and low levels of the digital signal. By switching the working mode of the rf switching module 705 and the working mode of the microwave switching module 805, fast inversion of two groups of effective raman laser wave vectors can be achieved.
The working principle of the present invention is further illustrated in the following examples of raman laser systems in combination with a cold atom level gravity gradiometer of the fountain type of Rb-87 atoms.
The two energy levels of the Rb-87 atom D2 line ground state are coupled by Raman transition, and the frequency difference of the two lasers (i.e. the first Raman laser and the second Raman laser) forming the two-photon Raman transition is equal to the frequency of the two energy levels of the ground stateDifference (D)Δω，Δ ω=6.834GHz。
The specific scheme is as follows:
1. the laser generating unit 1 selects an external cavity semiconductor laser and a conical laser amplifier, the working wavelength is 780nm, and the laser output by the external cavity semiconductor laser is amplified by the conical laser amplifier to generate about 1.5W of laser;
2. the laser output by the laser generating unit 1 is divided into two paths of laser with the same power through the laser beam splitting unit 2;
3. the first laser frequency shift unit 3 and the second laser frequency shift unit 4 both take acousto-optic modulators as cores, and act two paths of radio frequency signals output by the radio frequency generation unit 7 on the two acousto-optic modulators respectively;
4. the first electro-optical modulation unit 5 and the second electro-optical modulation unit 6 both use a free space type electro-optical phase modulator as a core device, and apply two paths of microwave signals output by the microwave generation unit 8 to the two electro-optical phase modulators respectively;
5. the radio frequency generation unit 7 outputs two paths of radio frequency signals with frequencies of 200MHz and 202MHz respectively to obtain a frequency difference valueδ=202MHz-200MHz =2 MHz; the microwave generating unit 8 outputs two paths of microwave signals with frequencies of 6.836GHz and 6.832GHz respectively;
6. when pi/2 Raman laser pulse acts, 200MHz and 202MHz radio frequency signals output by the radio frequency generating unit 7 act on the first laser frequency shifting unit 3 and the second laser frequency shifting unit 4 respectively; 6.836GHz and 6.832GHz microwave signals output by the microwave generating unit 8 respectively act on the first electro-optical modulating unit 5 and the second electro-optical modulating unit 6;
7. when pi Raman laser pulse acts, 202MHz and 200MHz radio frequency signals output by the radio frequency generating unit 7 act on the first laser frequency shifting unit 3 and the second laser frequency shifting unit 4 respectively; 6.832GHz and 6.834GHz microwave signals output by the microwave generating unit 8 are respectively applied to the first electro-optical modulating unit 5 and the second electro-optical modulating unit 6.
Specifically, as shown in fig. 6, the change of each laser frequency value when the pi/2-pi/2 raman laser pulse sequence is used to perform coherent operation on cold atoms in sequence is shown. In pi/2 Raman laser pulseFrequency of laser light in usef 1 、f 2 、f 3 、f 4 The following relationship is satisfied:
thus, when pi/2 Raman laser pulses are applied, the frequency isf 2 Andf 3 the laser of (a) constitutes a pair of Raman transitions at a frequency off 1 Andf 4 the laser light of (2) constitutes another pair of raman transitions and the effective wave vectors of the two pairs of raman transitions are in opposite directions, so that a dual raman transition can be realized.
As shown in fig. 6, when pi raman laser pulse acts, the high and low level conversion of the digital signal is controlled, and the working modes of the rf generating unit 7 and the microwave generating unit 8 are switched at the same time, so as to realize the inversion of the effective wave vector direction of the raman laser, at this time, the frequency of the laser is changedf 1 、f 2 、f 3 、f 4 The following relationship is satisfied:
in summary, the invention realizes a four-frequency double-raman laser system for a cold atom interferometer and a cold atom horizontal gravity gradient measurement method based on the four-frequency double-raman laser system. The scheme solves the problem of multiple interference paths when the three-frequency double-Raman technology is used for a cold atom horizontal gravity gradiometer system; compared with the traditional single Raman transition system, the double Raman transition realized by the scheme has the advantages that the measurement scale factor is doubled, atoms on two interference paths are in the same internal state, the measurement result is less sensitive to the environmental magnetic field noise, and the measurement precision can be effectively improved; by adopting the scheme, the rapid switching of the effective wave vector direction of the Raman laser can be realized.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A four-frequency double-Raman laser system is characterized by comprising a laser generating unit (1), a laser splitting unit (2), a first laser frequency shifting unit (3), a second laser frequency shifting unit (4), a first electro-optical modulating unit (5) and a second electro-optical modulating unit (6), wherein the output of the laser generating unit (1) is connected with the input of the laser splitting unit (2), the laser splitting unit (2) is provided with two output ends, one output end of the laser splitting unit (2), the first laser frequency shifting unit (3) and the first electro-optical modulating unit (5) are sequentially connected, and the other output end of the laser splitting unit (2), the second laser frequency shifting unit (4) and the second electro-optical modulating unit (6) are sequentially connected;
one laser beam output by the laser generating unit (1) passes through the laser splitting unit (2), the first laser frequency shift unit (3) and the second laser frequency shift unit (4) and then is divided into laser beams with the frequency off 1 Andf 2 two laser beams;
at a frequency off 1 Is modulated by a first electro-optical modulation unit (5) to generate a laser beam containingf 1 Andf 3 outputting the first Raman laser with two frequency components;
at a frequency off 2 Is modulated by a second electro-optical modulation unit (6) to generate a laser beam containingf 2 Andf 4 outputting the second Raman laser with two frequency components;
frequency off 1 、f 2 、f 3 、f 4 Satisfies the following conditions:f 1 ≠f 2 ，f 3 -f 1 ≠f 4 -f 2 ，f 4 -f 1 =f 3 -f 2 ；
at a frequency off 1 With a laser and a frequency off 4 The laser of (a) constitutes a first group of Raman lasers at a frequency off 2 With a laser and a frequency off 3 The effective wave vector directions of the two groups of Raman lasers are opposite, and the laser pulse sequences of pi/2-pi/2 act on atoms simultaneously.
2. The four-frequency double-Raman laser system according to claim 1, further comprising a radio frequency generating unit (7), wherein the radio frequency generating unit (7) is provided with two output ends, one output end of the radio frequency generating unit (7) is connected with the driving end of the first laser frequency shifting unit (3), and the other output end of the radio frequency generating unit (7) is connected with the driving end of the second laser frequency shifting unit (4); the radio frequency generating unit (7) is used for respectively driving the first laser frequency shifting unit (3) and the second laser frequency shifting unit (4).
3. The quad-frequency dual-Raman laser system according to claim 2, wherein the RF generating unit (7) comprises a first RF signal source (701), a second RF signal source (702), a first RF amplifying module (703), a second RF amplifying module (704), and an RF switching module (705); the radio frequency switching module (705) is provided with two channels, a first channel of the first radio frequency signal source (701), the first radio frequency amplification module (703) and the radio frequency switching module (705) is sequentially connected in series and then connected with the driving end of the first laser frequency shift unit (3), and a second channel of the second radio frequency signal source (702), the second radio frequency amplification module (704) and the radio frequency switching module (705) is sequentially connected in series and then connected with the driving end of the second laser frequency shift unit (4);
the first radio frequency signal source (701) and the second radio frequency signal source (702) generate two paths of radio frequency signals with different frequencies, the radio frequency signals are amplified by the first radio frequency amplification module (703) and the second radio frequency amplification module (704), and the two paths of radio frequency signals are output by the two channels of the radio frequency switching module (705) respectively and are used for driving the first laser frequency shift unit (3) and the second laser frequency shift unit (4) respectively.
4. The system of claim 3, wherein the RF switch module (705) comprises a first RF input channel, a second RF input channel, a first RF output channel, and a second RF output channel; the radio frequency switching module (705) can realize the following two signal output modes:
mode A: the output signal of the first radio frequency output channel is the same as the input signal of the first radio frequency input channel, and the output signal of the second radio frequency output channel is the same as the input signal of the second radio frequency input channel;
and (3) mode B: the output signal of the first radio frequency output channel is the same as the input signal of the second radio frequency input channel, and the output signal of the second radio frequency output channel is the same as the input signal of the first radio frequency input channel;
the switching between mode a and mode B is controlled by the high and low levels of the digital signal.
5. The four-frequency dual-Raman laser system according to claim 4, further comprising a microwave generating unit (8), wherein the microwave generating unit (8) has two output ends, one output end of the microwave generating unit (8) is connected to the driving end of the first electro-optical modulating unit (5), and the other output end of the microwave generating unit (8) is connected to the driving end of the second electro-optical modulating unit (6); the microwave generating unit (8) is used for respectively driving the first electro-optical modulating unit (5) and the second electro-optical modulating unit (6).
6. The four-frequency dual-Raman laser system according to claim 5, wherein the microwave generating unit (8) comprises a first microwave signal source (801), a second microwave signal source (802), a first microwave amplification module (803), a second microwave amplification module (804) and a microwave switching module (805), the microwave switching module (805) is provided with two channels, a first channel of the first microwave signal source (801), the first microwave amplification module (803) and the microwave switching module (805) is sequentially connected in series and then connected to the driving end of the first electro-optical modulation unit (5), and a second channel of the second microwave signal source (802), the second microwave amplification module (804) and the microwave switching module (805) is sequentially connected in series and then connected to the driving end of the second electro-optical modulation unit (6);
the first microwave signal source (801) and the second microwave signal source (802) generate two paths of microwave signals with different frequencies, the two paths of microwave signals are respectively amplified by the first microwave amplification module (803) and the second microwave amplification module (804), and then are respectively output by two channels of the microwave switching module (805) to be used for respectively driving the first electro-optical modulation unit (5) and the second electro-optical modulation unit (6).
7. The system of claim 6, wherein the microwave switching module (805) comprises a first microwave input channel, a second microwave input channel, a first microwave output channel, and a second microwave output channel; the microwave switching module (805) can realize the following two signal output modes:
and mode C: the output signal of the first microwave output channel is the same as the input signal of the first microwave input channel, and the output signal of the second microwave output channel is the same as the input signal of the second microwave input channel;
mode D: the output signal of the first microwave output channel is the same as the input signal of the second microwave input channel, and the output signal of the second microwave output channel is the same as the input signal of the first microwave input channel;
the switching between mode C and mode D is controlled by the high and low levels of the digital signal.
8. The method of claim 7, wherein the Raman laser is a four-frequency Raman laserThe laser system is characterized by further comprising a first Raman laser output unit (9) and a second Raman laser output unit (10), wherein the input of the first Raman laser output unit (9) is connected with the output of the first electro-optical modulation unit (5) and used for outputting a laser beam comprisingf 1 Andf 3 a first Raman laser of two frequency components; the input of the second Raman laser output unit (10) is connected with the output of the second electro-optical modulation unit (6), and the output comprisesf 2 Andf 4 a second Raman laser of two frequency components.
9. The cold atom horizontal gravity gradient measurement method based on the four-frequency dual-raman laser system of claim 7 or 8, comprising the steps of:
s1, system parameters are set, so that the frequency of the four output lasers is enabled to bef 1 、f 2 、f 3 Andf 4 satisfies the following conditions:f 1 ≠f 2 ，f 3 -f 1 ≠f 4 -f 2 ，f 4 -f 1 =f 3 -f 2 ；
s2, the output frequency component of the control system isf 1 Andf 3 the first Raman laser has a frequency component off 2 Andf 4 of a second Raman laser of (1), wherein the frequency isf 1 Andf 4 the two lasers form a first group of Raman lasers with the frequency off 2 Andf 3 the two lasers form a second group of Raman lasers, and the effective wave vector directions of the first group of Raman lasers and the second group of Raman lasers are opposite;
s3, the first group of Raman laser and the second group of Raman laser respectively act on atoms at the same time by using the Raman laser pulse sequence of pi/2-pi/2 to generate atom interference signals.
10. The cold atom horizontal gravity gradient measurement method of claim 9, wherein in step S3,
1.1 when the method is applied to an upper-throwing type atomic interferometer, the method has the following two working modes:
1.1.1 when the 1 st Raman laser pulse acts, the radio frequency switching module (705) works in a mode A, and the microwave switching module (805) works in a mode C; when the 2 nd Raman laser pulse acts, the radio frequency switching module (705) works in a mode B, and the microwave switching module (805) works in a mode D; when the 3 rd Raman laser pulse acts, the radio frequency switching module (705) works in a mode A, and the microwave switching module (805) works in a mode C;
1.1.2 when the 1 st Raman laser pulse acts, the radio frequency switching module (705) works in a mode B, and the microwave switching module (805) works in a mode D; when the 2 nd Raman laser pulse acts, the radio frequency switching module (705) works in a mode A, and the microwave switching module (805) works in a mode C; when the 3 rd Raman laser pulse acts, the radio frequency switching module (705) works in a mode B, and the microwave switching module (805) works in a mode D;
1.2 when the method is applied to a falling-type atomic interferometer, the method has the following two working modes:
1.2.1 when the whole pi/2-pi/2 Raman laser pulse sequence acts, the radio frequency switching module (705) works in a mode A, and the microwave switching module (805) works in a mode C;
1.2.2 when the whole pi/2-pi/2 Raman laser pulse sequence acts, the radio frequency switching module (705) works in the mode B, and the microwave switching module (805) works in the mode D.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007278768A (en) * | 2006-04-04 | 2007-10-25 | Toshiba Corp | Microscope device |
| CN103472495A (en) * | 2013-09-22 | 2013-12-25 | 中国科学院武汉物理与数学研究所 | Vertical gravity gradient measuring sensor based on atom interference effect |
| CN104737392A (en) * | 2012-07-05 | 2015-06-24 | 麦考瑞大学 | A laser and a method of controlling the generation of a light |
| CN107063480A (en) * | 2017-04-05 | 2017-08-18 | 中国科学院上海光学精密机械研究所 | Based on four-wave mixing scan-type ultrashort laser pulse time domain contrast measuring instrument |
| CN107328355A (en) * | 2017-09-01 | 2017-11-07 | 中国科学院武汉物理与数学研究所 | Integrated optical system for cold atom interferometer |
| CN212991572U (en) * | 2020-06-24 | 2021-04-16 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Compact laser system for atomic interferometer |
| CN112816456A (en) * | 2020-12-29 | 2021-05-18 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Integrated Raman laser system for cold atom horizontal gravity gradiometer |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7242517B2 (en) * | 2002-04-24 | 2007-07-10 | Pirelli & C. S.P.A. | Optical devices comprising series of birefringent waveplates |
| US8027032B2 (en) * | 2008-08-22 | 2011-09-27 | President & Fellows Of Harvard College | Microscopy imaging system and method employing stimulated raman spectroscopy as a contrast mechanism |
| FR3003949B1 (en) * | 2013-03-26 | 2015-05-01 | Univ Aix Marseille | STIMULATED RAMAN DETECTION DEVICE AND METHOD. |
| CN107015287B (en) * | 2017-03-09 | 2018-12-11 | 中国科学院电工研究所 | A kind of gradiometry device and measurement method |
-
2021
- 2021-09-02 CN CN202111028593.9A patent/CN113484921B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007278768A (en) * | 2006-04-04 | 2007-10-25 | Toshiba Corp | Microscope device |
| CN104737392A (en) * | 2012-07-05 | 2015-06-24 | 麦考瑞大学 | A laser and a method of controlling the generation of a light |
| CN103472495A (en) * | 2013-09-22 | 2013-12-25 | 中国科学院武汉物理与数学研究所 | Vertical gravity gradient measuring sensor based on atom interference effect |
| CN107063480A (en) * | 2017-04-05 | 2017-08-18 | 中国科学院上海光学精密机械研究所 | Based on four-wave mixing scan-type ultrashort laser pulse time domain contrast measuring instrument |
| CN107328355A (en) * | 2017-09-01 | 2017-11-07 | 中国科学院武汉物理与数学研究所 | Integrated optical system for cold atom interferometer |
| CN212991572U (en) * | 2020-06-24 | 2021-04-16 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Compact laser system for atomic interferometer |
| CN112816456A (en) * | 2020-12-29 | 2021-05-18 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Integrated Raman laser system for cold atom horizontal gravity gradiometer |
Non-Patent Citations (1)
| Title |
|---|
| "基于原子干涉仪的微观粒子弱等效原理检验";王谨 等;《物理学报》;20181231;第67卷(第16期);第160402-1至160402-12页 * |
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