阅读说明：本技术 基于双振子悬浮光力学系统的力场梯度测量装置及方法 (Force field gradient measuring device and method based on double-vibrator suspension optomechanics system ) 是由 李闯 董莹 胡慧珠 于 2021-09-15 设计创作，主要内容包括：本发明公开一种基于双振子悬浮光力学系统的力场梯度测量装置及方法。测量装置,依次包括激光器、光学腔、第一光镊、第二光镊、光场探测装置,其中光学腔中间分别设有第一纳米微粒和第二纳米微粒；激光器的光轴和光学腔的光轴重合,激光器从光学腔的左侧入射,在光学腔中激发形成稳定驻波场；第一光镊和第二光镊用于分别将相应的第一纳米微粒和第二纳米微粒悬浮在光学腔中,并调节它们沿光轴的位置；光场探测装置用于探测光学腔的腔透射光从而获取力差信息。本发明的梯度测量方法可探测力场的瞬时梯度,监控场的动态变化。本发明不仅适用于引力场,对于加速度场、电场等同样适用。本发明可促进悬浮光力学在场探测和多点传感领域的发展应用。(The invention discloses a force field gradient measuring device and method based on a double-vibrator suspension optomechanics system. The measuring device sequentially comprises a laser, an optical cavity, first optical tweezers, second optical tweezers and an optical field detection device, wherein the middle of the optical cavity is respectively provided with first nanoparticles and second nanoparticles; the optical axis of the laser is coincided with the optical axis of the optical cavity, the laser enters from the left side of the optical cavity and is excited in the optical cavity to form a stable standing wave field; the first optical tweezers and the second optical tweezers are used for respectively suspending the corresponding first nanoparticles and second nanoparticles in the optical cavity and adjusting the positions of the first nanoparticles and the second nanoparticles along the optical axis; the light field detection device is used for detecting cavity transmission light of the optical cavity so as to acquire force difference information. The gradient measuring method can detect the instantaneous gradient of the force field and monitor the dynamic change of the field. The invention is not only suitable for gravitational fields, but also suitable for acceleration fields, electric fields and the like. The invention can promote the development and application of suspension optomechanics in the field detection and multipoint sensing fields.)

1. A measuring device based on force field gradient of a double-vibrator suspension optomechanical system is characterized by sequentially comprising a laser (1), an optical cavity (2), a first optical tweezer (3), a second optical tweezer (4) and an optical field detection device (5), wherein a first nanoparticle (6) and a second nanoparticle (7) are respectively arranged in the middle of the optical cavity (2);

the optical axis of the laser (1) is coincident with the optical axis of the optical cavity (2), the laser (1) enters from the left side of the optical cavity (2) and is excited in the optical cavity (2) to form a stable standing wave field; the first optical tweezers (3) and the second optical tweezers (4) are used for respectively suspending corresponding first nanoparticles (6) and second nanoparticles (7) in the optical cavity (2) and adjusting the positions of the first nanoparticles and the second nanoparticles along the optical axis; the light field detection device (5) is used for detecting cavity transmission light of the optical cavity (2) so as to acquire force difference information.

2. The double-pendulum suspended photodynamic system force field gradient-based measurement device according to claim 1, wherein the light field detection device (5) is a homodyne detection device or a heterodyne detection device.

3. A method for measuring force field gradient based on a double-vibrator suspended optomechanical system by using the measuring device of claim 1, comprising the following steps:

s1, turning on the laser (1) to drive the optical cavity (2) to generate a standing wave field in the cavity;

s2 suspending the corresponding first nanoparticle (6) and second nanoparticle (7) in the optical cavity (2) using the first optical tweezers (3) and the second optical tweezers (4), respectively;

s3 the positions of the first nanometer particle (6) and the second nanometer particle (7) are adjusted through the first optical tweezers (3) and the second optical tweezers (4), and the position difference is recorded；

S4 measuring the cavity transmitted light through the light field detection device (5) to obtain the stress difference of the first nanometer particle (6) and the second nanometer particle (7)；

S5 according to force differenceAnd difference in positionThe force field gradient is calculated.

4. The measurement method according to claim 3, wherein the positions of the first nanoparticle (6) and the second nanoparticle (7) are adjusted by using the first optical tweezers (3) and the second optical tweezers (4) in step S3 such that the difference between the positions of the two nanoparticles along the optical axis direction satisfiesWhereinIs a standing wave field in the cavity, and n is an integer.

Technical Field

The invention relates to force field gradient measurement, in particular to a force field gradient measurement device and method based on a double-vibrator suspension optomechanics system.

Background

Since the aster ashiki optical tweezers technology of the seventies of the last century, optical tweezers have been widely used in the fields of biology, material science, quantum physics, and the like as a beneficial tool for manipulating nanoscale objects. The suspended optomechanical system formed by suspending the nanoscale particles by using the optical tweezers can overcome noise caused by mechanical support, and has ultrahigh detection sensitivity. The suspension optomechanical system also has super-strong control capability and can flexibly control the position and the state of the nanometer particles (mechanical vibrators). These advantages make suspended optomechanical systems one of the more popular research directions in the field of precision measurement and sensing in recent years.

The detection device based on the single-vibrator suspension optomechanical system is characterized in that a nanometer microsphere (mechanical vibrator) is suspended in vacuum by using optical tweezers, and the microsphere performs micro simple harmonic motion in an optical trap generated by the optical tweezers. The movement (displacement) of the microspheres can be changed under the action of the external force to be detected on the microspheres, the change can be reflected in scattered light of the small spheres, and external force detection is realized by measuring the scattered light. Because only one mechanical vibrator is provided, the detection device based on the single-vibrator suspension optomechanical system can only detect the stress information of a certain spatial position at a time, and cannot simultaneously obtain the stress information of a plurality of spatial positions, so that the gradient detection of a force field cannot be realized. Even if the mechanical vibrator position is changed to carry out measurement for many times, only the stress information of different space positions at different times can be obtained, and the instantaneous gradient of the force field cannot be detected.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a force field gradient detection device and method based on a double-vibrator suspension optomechanics system.

The purpose of the invention is realized by the following technical scheme:

a measuring device based on force field gradient of a double-vibrator suspension optomechanics system sequentially comprises a laser, an optical cavity, a first optical tweezer, a second optical tweezer and an optical field detection device, wherein a first nanoparticle and a second nanoparticle are respectively arranged in the middle of the optical cavity;

the optical axis of the laser is coincided with the optical axis of the optical cavity, the laser enters from the left side of the optical cavity and is excited in the optical cavity to form a stable standing wave field; the first optical tweezers and the second optical tweezers are used for respectively suspending the corresponding first nanoparticles and second nanoparticles in the optical cavity and adjusting the positions of the first nanoparticles and the second nanoparticles along the optical axis; the light field detection device is used for detecting cavity transmission light of the optical cavity so as to acquire force difference information.

The light field detection device is a homodyne detection device or a heterodyne detection device.

A measuring method based on force field gradient of a double-vibrator suspension optomechanical system by adopting the measuring device comprises the following steps:

s1: opening a laser driving optical cavity to generate a standing wave field in the cavity;

s2: suspending the respective first and second nanoparticles in the optical cavity using the first and second optical tweezers, respectively;

s3: the positions of the first nanometer particles and the second nanometer particles are adjusted through the first optical tweezers and the second optical tweezers, and the position difference is recorded；

S4: measuring cavity transmitted light through an optical field detection device to obtain the stress difference of two nano particles (mechanical vibrators)；

S5: according to the difference in forceAnd difference in positionThe force field gradient is calculated.

In step S3, the positions of the first nanoparticle and the second nanoparticle are adjusted by using the first optical tweezers and the second optical tweezers, so that the difference between the positions of the two nanoparticles along the optical axis direction satisfiesWhereinIs a standing wave field in the cavity, and n is an integer.

The invention has the following beneficial effects:

(1) the method is not only suitable for gravitational fields, but also suitable for acceleration fields, electric fields and the like, and can promote the development and application of suspension optomechanics in the field detection and multipoint sensing fields.

(2) The method and the device can eliminate partial homologous noise by detecting the gradient of the force field and improve the signal-to-noise ratio.

(3) The device has the detection sensitivity which is the same as that of the traditional single-vibrator suspension-based photodynamic system.

Drawings

FIG. 1 is a schematic view of an apparatus of the present invention;

in fig. 1, a laser 1, an optical cavity 2, a first optical tweezer 3, a second optical tweezer 4, an optical field detection device 5, a first nanoparticle 6, and a second nanoparticle 7.

FIG. 2 is a schematic diagram of gradient measurement in the method of the present invention.

FIG. 3 is a flow chart of the method of the present invention.

FIG. 4 shows the result of numerical simulation of an external force field F acting on the gradient measuring device;

whereinExternal force field in placeAndrespectively acting forces onAnd，in order to be able to determine the amplitude of the force,in order to be the frequency of the applied force,is the mechanical vibrator resonance frequency. In the figure, (a) is the power spectral density of the mechanical vibrator displacement difference Q, and (b) is the cavity transmission light(ii) power spectral density of (c) is the force differenceOf the power spectral density of (c).

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments, and the objects and effects of the present invention will become more apparent, it being understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

The invention relates to a force field gradient detection device based on a double-vibrator suspension photodynamic system, which is characterized in that two optical tweezers are used for respectively suspending two nano microspheres in an optical cavity to form the double-vibrator suspension photodynamic system. Wherein the optical cavity is driven by an external laser and the light field detection means is arranged to detect cavity transmitted light.

As shown in fig. 1, the device of the present invention includes, as one embodiment, a laser 1, an optical cavity 2, a first optical tweezer 3, a second optical tweezer 4, an optical field detection device 5, a first nanoparticle 6, and a second nanoparticle 7.

The optical axis of the laser 1 and the optical axis of the optical cavity 2 coincide and the optical cavity 2 is driven from the left for forming a standing wave field. The first optical tweezers 3 and the second optical tweezers 4 suspend first nanoparticles 6 and second nanoparticles 7, respectively, in the optical cavity 2. The coupling strength of the nanoparticles and the cavity field is changed by adjusting the position of the two nanoparticles along the optical axis. The light field detection means 5 detects the cavity transmitted light for acquiring a force difference signal.

The force field gradient detection principle of the invention is (see fig. 2): two optical tweezers respectively drive two nano particles (mechanical vibrators) at respective balance positionsAndperforming a slight harmonic motion with a positional difference of. The balance positions of the two mechanical oscillators can be controlled by the optical tweezers, and the position difference can reach the micron order based on the prior art. Acting force of one force field to be measured on two mechanical vibratorsAndwill change their simple harmonic motion displacementAndand two mechanical vibrators are coupled with the cavity field simultaneously, so that the force field informationAndwill be coupled into the cavity field through optical force interaction (optomechanical interaction), and the force field information can be obtained by measuring the cavity field. To achieve a difference in forceDirect coupling into the cavity field requires adjustment of the mechanical vibrator to cavity field coupling strength. The strength of the coupling of the mechanical vibrator to the cavity field is related to its position in the cavity (along the cavity axis), i.e.WhereinIs the wavelength of the cavity field and is,the serial number of the mechanical vibrator. When the position difference of the two mechanical vibrators is satisfied （Is an integer), the difference between the two mechanical oscillator forcesWill be subject to displacement differenceThe device is directly coupled into a cavity field, and the stress difference of the two mechanical vibrators can be directly obtained in cavity transmitted light through a light field detection device. In this way, force field gradient detection can be achieved。

As shown in fig. 3, the method for measuring the force field gradient based on the double-vibrator suspension optomechanics system specifically includes the following steps:

s1: the laser 1 is turned on to drive the optical cavity 2 to produce a wavelength in the cavity ofThe standing wave field of (a);

s2: suspending a first nanoparticle 6 and a second nanoparticle 7 in the optical cavity 2 using a first optical tweezer 3 and a second optical tweezer 4, respectively;

s3: the positions of the two nano particles are adjusted by the first optical tweezers 3 and the second optical tweezers 4 to ensure that the position difference along the cavity axis direction meets the requirement（Is an integer), recording position difference；

S4: measuring cavity transmitted light through the light field detection device 5 to obtain the stress difference；

S5: according to the difference in forceAnd difference in positionCalculating force field gradients。

The apparatus and method of the present invention are described below in a specific embodiment.

Considering an external force field varying with time between two distancesRespectively acting forces on the mechanical vibrator areAndwherein, in the step (A),in order to be able to determine the amplitude of the force,in order to be the frequency of the applied force,is the cavity field wavelength. The gradient probe parameters were as follows (all parameters were normalized with the mechanical vibrator frequency as standard unit): two identical nanoparticles (mechanical vibrator) having a mass m and a resonance frequencyAttenuation rate of(ii) a Cavity field and laser field detuning amount(ii) a Rate of cavity decay(ii) a Coupling strength of two mechanical vibrators and cavity field. Assuming the amplitude of the applied force of the external force fieldFrequency of applied force is taken separatelyThree cases.

The results of the force field gradient detection process are numerically simulated by using quantum principal equation as shown in FIG. 4, wherein (a) is the power spectral density of the mechanical vibrator displacement difference Q, and (b) is the cavity transmitted light(ii) power spectral density of (c) is the force differenceOf the power spectral density of (c). As can be seen from the figure, under the condition of external force fields with three different frequencies, the detection device can obtain a force difference signal from cavity transmitted light, which shows that the force field gradient measurement method can realize the force field gradient detection.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and although the invention has been described in detail with reference to the foregoing examples, it will be apparent to those skilled in the art that various changes in the form and details of the embodiments may be made and equivalents may be substituted for elements thereof. All modifications, equivalents and the like which come within the spirit and principle of the invention are intended to be included within the scope of the invention.