阅读说明：本技术 一种宽频声光移频系统 (Broadband acousto-optic frequency shift system ) 是由 吴季 王城强 许智宏 李锟影 陈伟 张星 陈秋华 于 2020-06-10 设计创作，主要内容包括：本发明公开了一种宽频声光移频系统。本发明描述的宽频声光移频系统,包括声光移频器①,反射镜②,棱镜③。能量守恒定律指出,能量既不会凭空产生,也不会凭空消失,它只会从一种形式转化为另一种形式,或者从一个物体转移到其他物体。声光互作用过程也符合这一定律,产生衍射以后,光的能量将发生改变,导致光的移频。当入射光以布拉格角入射时,产生的1级衍射光以相同的方向返回到声光介质中时,返回的光入射角仍然与布拉格角相等,即满足布拉格匹配,此时返回的入射光也将发生衍射,并且衍射级与初始入射光同向。因此,我们只需要通过控制初次衍射光是否需要再进入声光介质,在常规一次穿过频移量的基础上,就能进一步实现更大频移量的获取。(The invention discloses a broadband acousto-optic frequency shift system. The invention describes a broadband acousto-optic frequency shift system which comprises an acousto-optic frequency shifter, a reflector and a prism. The law of conservation of energy states that energy is neither generated nor lost by void, it is only converted from one form to another, or it is transferred from one object to another. The acousto-optic interaction process also conforms to the law, and after diffraction is generated, the energy of light is changed, so that the frequency shift of the light is caused. When the incident light is incident at the Bragg angle and the generated 1 st order diffracted light returns to the acousto-optic medium in the same direction, the returned light incident angle is still equal to the Bragg angle, namely Bragg matching is satisfied, the returned incident light will be diffracted at the moment, and the diffraction order is in the same direction as the initial incident light. Therefore, the acquisition of a larger frequency shift amount can be further realized on the basis of the conventional one-time passing frequency shift amount only by controlling whether the primary diffracted light needs to enter the acousto-optic medium again.)

1. The invention discloses a broadband acousto-optic frequency shift system which is characterized by being capable of realizing large frequency shift amount by using a single acousto-optic frequency shifter.

2. The light deflecting mirror (c), the prism (c) according to claim 1 is designed as an adjustable structure.

3. The light deflecting mirror according to claim 1 may be a mirror, a prism, or the like that causes deflection of an optical path.

4. Prism according to claim 1, which may be a mirror, prism or the like, which may cause deflection of the optical path.

Technical Field

The invention relates to an acousto-optic system, in particular to a broadband acousto-optic frequency shift system.

Background

Acousto-optic interaction refers to the phenomenon that light waves are diffracted or scattered by an ultrasonic field when propagating in a medium. Since the acoustic wave is an elastic wave, the phenomenon that the acoustic wave propagates in the medium to generate elastic stress or strain is called as an elasto-optical effect, and the refractive index of the medium is changed due to the elastic deformation of the medium. When light waves propagate in a medium, a diffraction phenomenon occurs, and the intensity, frequency, direction and the like of diffracted light are changed along with the change of an ultrasonic field. By using the principle, an acousto-optic device is developed, but because the frequency shift and deflection angle generated by the acousto-optic device are very small, the acousto-optic device has no practical value for incoherent light, and therefore laser is not available and is not practically applied. The discovery of the laser thoroughly changes the situation, and because the laser beam has a series of characteristics of good monochromaticity, good directivity, high brightness, the energy of the whole laser beam can be completely focused in a light spot with the size of diffraction limit, and the like, the frequency, the phase, the amplitude or the intensity of the laser can be modulated through the acousto-optic device, the transmission and the conversion among electric, sound and optical information can be rapidly completed, the propagation direction of the laser beam can be randomly changed, and the automatic frequency selection, the light splitting, the scanning and the like of the laser beam can be realized. In light of these characteristics, acousto-optic devices have gained increasing attention.

The acousto-optic frequency shifter is one of numerous acousto-optic devices, mainly functions in shifting the laser working frequency on the original basic frequency, has the characteristics of high frequency shifting precision, good stability, convenience in use and the like, and is mainly applied to the fields of heterodyne detection, speed measurement, optical gyros and the like. Generally, the frequency shift amount of the acousto-optic frequency shifter cannot be made very large, and in some special applications, if a large frequency shift amount is to be obtained, the problem can be solved only by increasing the number of frequency shifters in the system. This not only complicates the system, but also increases the cost significantly. The invention aims to solve the problem and design a broadband acousto-optic frequency shift system which is low in cost and convenient to operate.

Disclosure of Invention

The invention discloses a broadband acousto-optic frequency shift system.

The invention describes a broadband acousto-optic frequency shift system which comprises an acousto-optic frequency shifter, a reflector and a prism.

The law of conservation of energy states that energy is neither generated nor lost by the void, it is only converted from one form to another, or it is transferred from one object to another, and the total amount of energy remains the same. The acousto-optic interaction process also follows this law, and we can thus derive the relationship between incident light and diffracted light frequency, i.e.:

ω_i±ω_s=ω_d

wherein ω is_iIs the frequency of the incident light, omega_sIs the frequency of sound waves in the medium, omega_dThe first order diffracted light frequency. It is known that when incident light is incident at the bragg angle and the generated 1 st order diffracted light returns to the acousto-optic medium in the same direction, the angle of incidence of the returned light is still equal to the bragg angle, i.e. bragg matching is satisfied, at which time the returned incident light will also be diffracted and the diffracted order passes through with the original incident light. The frequency relationship between the incident light and the final diffracted light is:

ω_i±2ω_s=ω^’ _d

ω^’ _dthe frequency of the resulting diffracted light. Therefore, the acquisition of a larger frequency shift amount can be further realized on the basis of the conventional one-time passing frequency shift amount only by controlling whether the primary diffracted light needs to enter the acousto-optic medium again. The invention has the advantages that: the acousto-optic frequency shift system has compact structure and convenient adjustment, and can obtain the adjustment of large frequency shift amount only by a single acousto-optic frequency shifter.

Drawings

FIG. 1 is a diagram showing the operation of a broadband acousto-optic frequency shift system;

FIG. 2 is another operational illustration of a wideband acousto-optic frequency shift system.

Detailed Description

The invention will be further described with reference to the following examples with reference to the accompanying drawings.

As shown in FIG. 1, the acousto-optic frequency shifter ①, the optical deflection mirror ② and the prism ③ form a complete broadband acoustic signalWhen the acousto-optic frequency shifter ① starts to work under the driving action, incident light is incident at a Bragg angle, and diffracted light is generated after passing through the device under the influence of acousto-optic interaction, at the moment, the optical deflector ② is adjusted to enable the diffracted light to deviate from the prism ③ to be directly output, in the figure 1, the positive first-order diffracted light is taken as an example, the incident light frequency is set to be omega_iThe working frequency of the acousto-optic frequency shifter is omega₁~ω₂In this operation state, the frequency shift of the light is ω₁~ω₂The resulting optical frequency is (ω)_i+ω₁）~（ω_i+ω₂）。

FIG. 2 is another operation diagram of the system, in which when the acousto-optic frequency shifter ① starts to operate under driving action, the incident light is incident at a Bragg angle, and the acousto-optic interaction affects the diffracted light generated by the device, at this time, the light deflecting mirror ② is adjusted not to affect the diffracted light to enter the prism ③, and the prism ③ is adjusted to return the diffracted light to the acousto-optic medium again, so that the light incident to the acousto-optic medium again is parallel to the diffracted light₁~2ω₂) The resulting optical frequency is (ω)_i+2ω₁）~（ω_i+2ω₂）。

Therefore, the whole system can realize the frequency shift amount of (ω)₁~ω₂）+（2ω₁~2ω₂). Theoretically, by using a similar structure, multiple diffraction can be performed, the frequency shift amount of the system is further increased, but the system is used in series with a plurality of frequency shifters, and larger loss is brought.