CN1696653A - Measuring Method of Kashmir Force in Rectangular Cavity - Google Patents

Abstract

A method for measuring Casimir force in rectangular cavity utilizes physical structure formed by scan - probe microscope, corp probe, specially made rectangular cavity and planar composite substrate and applies D - value of planar portion to rectangular cavity portion to realize indirect measurement of Casimir force in rectangular cavity.

Description

Measuring Method of Kashmir Force in Rectangular Cavity

technical field

The invention relates to a method for measuring force, in particular to a method for measuring Kashmir force in a rectangular cavity.

Background technique

With the development of micromachines, the characteristic size of the mechanism is getting smaller and smaller, resulting in a rapid reduction in the mass of the parts. Neglected quantum effects become important and sometimes have become the key to the normal operation of certain micromechanical systems. In the long-range quantum force, it is generally believed that the long-range quantum force acting within 20nm is Van der Waals force (Van der Waals), while the long-range quantum force outside 20nm is called Casimir force.

Since Casimir proposed the existence of Casimir force between two parallel planes through zero-point energy, and proposed the calculation formula of Casimir, people have been trying to measure the Casimir force, and compared and corrected it with the theoretical formula. Although the Casimir force can be regarded as a quantum force under macroscopic conditions, its value depends entirely on the size of the distance, and its value is very small under the condition of the smallest size that can be provided by previous measurement methods. For example, under ideal conditions, the Casimir force between two parallel planes with a distance of 1 μm and an area of 1 cm ² is only 10 ^-7 N, which is a big challenge for the previous test equipment. The atomic force microscope (AFM) has the highest precision among all the instruments used to measure the Casimir force. It can not only accurately measure the Casimir force between objects, but also eliminate the influence of electrostatic force. At the same time, the experimental conditions of vacuum environment can eliminate the influence of dust in the air. What's more commendable is that AFM can also make a detailed analysis of the surface topography of the plane. Accurate measurement, there is no literature report on the measurement of Casimir force in a rectangular cavity by using an atomic force microscope as a test method.

Contents of the invention

The purpose of the present invention is to use the existing AFM and slightly improve it to realize the effective measurement of the Casimir force in the rectangular cavity.

The invention provides a method for measuring the Kashmir force in a rectangular cavity, which is realized in the atomic force microscope (AFM) mode on a multifunctional scanning probe microscope, and the surface potential energy of the main microscope is tested similarly to its routine The modification method at the time is modified, and its probe is replaced with a planar probe. The size of the planar probe is between 6 and 10 μm. The substrate adopts a composite structure of a rectangular cavity and a plane, and the size is 20×10×2 μm～ Between 40×20×4μm, at the same time, the rectangular cavity on the substrate requires that the dimensions of the three sides are between 100 and 1000nm, the ratio of the length and height to the width is greater than 3, and the thickness of the plate between the cavities is less than 150nm , when the flat probe is facing the plane part of the substrate, two parallel plane structures are formed, and a measurement value 1 is obtained, and then the flat probe of the AFM is moved above the rectangular cavity structure on the substrate, and the measurement value 2 is obtained, and the measurement value 2 The value of the Casimir force in the rectangular cavity structure can be obtained by subtracting the measured value 1.

On the premise that there is no Casimir force related measurement in the rectangular cavity, the present invention provides a method for measuring the Casimir force in the rectangular cavity. At the same time, it is combined with two parallel plane structures, and indirectly realizes the rectangular cavity through the two parallel plane structures. Measurement of intraluminal Casimir forces.

Description of drawings

Figure 1 Schematic diagram of the planar probe provided by Nanoword

Figure 2 Schematic diagram of the substrate

Figure 3 Schematic diagram of a rectangular cavity on a substrate

Figure 4 is the effect diagram when measuring the composite structure of rectangular cavity and plane, in which the yellow plane represents the plane probe, and the blue part represents the substrate.

Detailed ways

The working process according to the present invention is described in detail in conjunction with the measurement effect Fig. 3 .

First of all, a certain modification was carried out on the atomic force microscope of DI Company in the United States, and the probe was replaced with a flat-head probe provided by Nanoworld Company of Germany, and the size was selected as 6 μm. The overall size of the pedestal is selected as 20×10×2μm, of which the planar part and the rectangular cavity part each occupy 10μm, the size of the rectangular cavity is 1000×100×600nm, and the thickness of the plate between the cavity and the cavity is 100nm. The selection of these dimensions, The limitation of the existing manufacturing technology is mainly considered. The pedestal is processed using an electron beam nanolithography system.

When the flat probe of the AFM is facing the plane part of the substrate, two parallel plane structures are formed. At this time, the calculation formulas of the zero-point energy and the Casimir force in the two parallel plane structures are still applicable, because the distance between the two planes is the same as that of the probe. The size of the needle is still very small compared to the calculation formula under ideal conditions. The measured result at this time should be the result of two parallel planes. However, when the flat probe of AFM moves above the rectangular cavity structure on the substrate, it cannot simply be calculated with the formula for calculating the zero-point energy in the rectangular cavity. It can be considered that a rectangular cavity is added on the basis of two parallel planes. structure, so the obtained measurement results can be considered as a composite structure composed of two parallel plane structures and a rectangular cavity structure, and the result of the Casimir force in the rectangular cavity structure can be obtained by subtracting the measured results of the two parallel planes from the measurement results.

Claims (1)

1, a kind of measuring method of Kashmir force in a rectangular cavity, it is characterized in that: the method is realized under the atomic force microscope (AFM) mode on the multi-function scanning probe microscope, to main microscope by similar its conventional test surface The modification method of potential energy is modified, and its probe is replaced with a planar probe. The size of the planar probe is between 6 and 10 μm. The substrate adopts a composite structure of a rectangular cavity and a plane, and the size is 20×10×2 μm. ~40×20×4μm, at the same time, the rectangular cavity on the substrate requires that the dimensions of the three sides are between 100-1000nm, the ratio of the length and height to the width is greater than 3, and the thickness of the plate between the cavities is less than 150nm, when the flat-tip probe is facing the plane part of the substrate, two parallel plane structures are formed, and a measurement value 1 is obtained, and then the flat-tip probe of the AFM is moved above the rectangular cavity structure on the substrate, and the measurement value 2 is obtained. The magnitude of the Casimir force in the rectangular cavity structure can be obtained by subtracting the measured value 1 from 2.

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