TWI400436B - Method and device for measuring a polarizing direction of an electromagnetic wave - Google Patents

Description

Electromagnetic wave polarization direction detecting method and detecting device

The invention relates to a method and a detection device for detecting a polarization direction of an electromagnetic wave, in particular to a method and a detection device for detecting a polarization direction of an electromagnetic wave based on a carbon nanotube.

The polarization direction is an important property of electromagnetic waves. Conventionally, the method of detecting the polarization direction of visible light is generally to place a polarizing plate on a propagation path of a beam of light, rotate the polarizing plate and observe a change in the projection brightness of the optical signal passing through the polarizing plate. When the brightness is maximum, the polarization direction of the optical signal is parallel to the polarization direction of the polarizing plate. When the brightness is minimum, the polarization direction of the optical signal is perpendicular to the polarization direction of the polarizing plate. The conventional detection of visible light intensity is generally judged by directly observing the brightness of the visible light signal. However, for the polarization direction of infrared, ultraviolet or other wavelength electromagnetic signals that the human eye cannot perceive, it is not possible to directly detect the brightness change of the optical signal projection. Generally, when the detected optical signal is infrared light, ultraviolet light or electromagnetic waves of other wavelengths, a photoelectric sensor is disposed on the optical path after polarization of the polarizing plate, thereby converting the optical signal into an electrical signal, and detecting the rotation During the process of the polarizing plate, the intensity of the electric signal changes, thereby obtaining a change in the intensity of the light. However, this method requires a large number of optical and electronic devices, which is complicated. In addition, the prior polarizing plates generally have good polarization properties only for electromagnetic waves of a certain wavelength band (such as microwave, infrared light, visible light, ultraviolet light, etc.), and cannot have uniform polarization absorption characteristics for electromagnetic waves of various wavelengths. Therefore, when the wavelength of the electromagnetic wave signal to be measured changes, it is necessary to use different polarizing plates to detect it.

Since the early 1990s, nanomaterials represented by carbon nanotubes have attracted great attention due to their unique structure and properties. In recent years, with the deepening of research on carbon nanotubes and nanomaterials, its broad application prospects have been continuously revealed. For example, the carbon nanotubes have uniform absorption characteristics for electromagnetic waves of various wavelengths, and when electromagnetic waves of different wavelengths are irradiated to a carbon nanotube structure, the resistance of the carbon nanotube structure changes accordingly, and the variation law can be utilized. For the detection of the intensity of electromagnetic waves, see "Bolometric infrared photoresponse of suspended single-walled carbon nanotube films", Science, Mikhail E. Itkis et al, vol 312, P412 (2006). The paper discloses an electromagnetic wave detecting device for a disordered carbon nanotube film, the structure comprising a disordered carbon nanotube film sensor and two electrodes electrically connected to the disordered carbon nanotube film sensor. When the electromagnetic waves of different intensities illuminate the disordered carbon nanotube film sensor, the resistance of the disordered carbon nanotube film is different, so the electromagnetic wave can be measured by measuring the resistance of the disordered carbon nanotube film sensor. strength. However, the electromagnetic wave detecting device cannot detect the polarization direction of the electromagnetic wave.

In view of the above, it is necessary to provide a method and a detection device for detecting the polarization direction of electromagnetic waves. The detection method of the polarization direction of the electromagnetic wave is simple, and the polarization direction of the electromagnetic wave can be detected without using complicated optical and electronic devices.

A method for detecting polarization direction of electromagnetic waves, comprising the steps of: placing a carbon nanotube structure in a vacuum environment, the carbon nanotube structure comprising a plurality of carbon nanotubes arranged in the same direction; providing an electromagnetic wave emission Source, emitting a polarized electromagnetic wave and causing it to be incident substantially perpendicularly to the surface of the carbon nanotube structure, the carbon nanotube structure absorbing the electromagnetic wave and emitting light; rotating in a plane substantially perpendicular to an incident direction of the electromagnetic wave The carbon nanotube structure determines the polarization direction of the electromagnetic wave according to a change in visible light emitted by the carbon nanotube structure.

An electromagnetic wave polarization direction detecting device includes: a vacuum chamber having an incident window and an observation window; wherein the electromagnetic wave polarization direction detecting device further comprises a carbon nanotube structure, the carbon nanotube structure Included in the plurality of carbon nanotubes arranged in the same direction, the carbon nanotube structure is disposed in the vacuum chamber, the incident window is opposite to the carbon nanotube structure and spaced apart, and the electromagnetic wave to be tested is incident through the incident window To the surface of the carbon nanotube structure.

Compared with the prior art, the electromagnetic wave polarization direction detecting method changes the angle between the extending direction of the length of the carbon nanotube and the polarization direction of the electromagnetic wave in the carbon nanotube structure only by rotating the carbon nanotube structure, and During the change process, the polarization direction of the incident electromagnetic wave can be judged by detecting the change of the visible light of the carbon nanotube structure, and the method is simple; in the electromagnetic wave polarization direction detecting device, since the carbon nanotube structure is composed only of a plurality of nanometers The carbon tube is composed of a simple structure, which is advantageous for reducing the manufacturing cost of the electromagnetic wave polarization direction detecting device and the cost of applying the device for detecting.

Hereinafter, a method of detecting an electromagnetic wave polarization direction according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1 and FIG. 2 together, an embodiment of the present invention provides an electromagnetic wave bias. The detection method of the vibration direction mainly includes the following steps: Step 1: providing an electromagnetic wave polarization direction detecting device 10, the electromagnetic wave polarization direction detecting device 10 includes a vacuum chamber 12 and a nano carbon disposed in the vacuum chamber 12 Tube structure 14.

The carbon nanotube structure 14 includes a plurality of carbon nanotubes arranged in the same direction. The so-called arrangement in the same direction means that at least most of the carbon nanotubes are arranged in the same direction and have a certain regularity, such as being substantially along a fixed direction. Orientation. The carbon nanotubes include one or more of a single-walled carbon nanotube, a double-walled carbon nanotube, or a multi-walled carbon nanotube. The single-walled carbon nanotube has a diameter of 0.5 nm to 50 nm. The double-walled carbon nanotube has a diameter of 1.0 nm to 50 nm. The multi-walled carbon nanotube has a diameter of 1.5 nm to 50 nm.

The carbon nanotube structure 14 is a self-supporting structure. The so-called self-supporting structure means that the carbon nanotube structure can maintain its own specific shape without being supported by a support. The self-supporting structure includes a plurality of carbon nanotubes that are attracted to each other by a van der Waals force, so that the carbon nanotube structure has a specific shape. Specifically, the carbon nanotube structure includes at least one carbon nanotube film, at least one nano carbon line structure, or a combination thereof.

The carbon nanotube film comprises a carbon nanotube film, a ribbon carbon nanotube film or a long carbon nanotube film.

The carbon nanotube film is directly obtained by drawing an array of carbon nanotubes, preferably directly by drawing a super-sequential carbon nanotube array. The carbon nanotubes in the carbon nanotube film are selected in the same direction end to end. Orientation arrangement, please refer to FIG. 3 and FIG. 4 . Specifically, each carbon nanotube film comprises a plurality of continuous and aligned carbon nanotube segments 143, and the plurality of carbon nanotube segments 143 are passed through Van der Waals. The force is connected end to end, and each of the carbon nanotube segments 143 includes a plurality of substantially parallel carbon nanotubes 145 which are tightly coupled by van der Waals forces. The carbon nanotube segment 143 has any width, thickness, uniformity, and shape. The carbon nanotube film has a thickness of 0.5 nm to 100 μm. For the structure of the carbon nanotube film and the preparation method thereof, refer to Taiwan Patent Application No. 200833862, which was published on August 16, 2008 by Fan Shoushan et al.

The ribbon-shaped carbon nanotube film is obtained by pouring an elongated carbon nanotube array perpendicular to the length of the carbon nanotube array on a substrate surface. The ribbon-shaped carbon nanotube film comprises a plurality of carbon nanotubes arranged in a preferred orientation. The plurality of carbon nanotubes are arranged substantially parallel to each other in parallel, and are closely coupled by a van der Waals force, the plurality of carbon nanotubes having substantially equal lengths and having a length in the order of millimeters. The width of the ribbon-shaped carbon nanotube membrane is equal to the length of the carbon nanotube, so that at least one carbon nanotube in the ribbon-shaped carbon nanotube array extends from one end of the ribbon-shaped carbon nanotube membrane to another One end, thus spanning the entire strip of carbon nanotube membrane. The width of the ribbon-shaped carbon nanotube film is limited by the length of the carbon nanotube. Preferably, the carbon nanotube has a length of from 1 mm to 10 mm. The structure of the ribbon-shaped carbon nanotube film and the preparation method thereof are described in Taiwan Patent Application No. 97,212,118, filed on Jun. 13, 2008.

The long carbon nanotube film is obtained by a kite flying method, and the long carbon nanotube film comprises a plurality of ultra-long carbon nanotubes parallel to the surface of the carbon nanotube film. And the plurality of carbon nanotubes are arranged substantially parallel to each other. The plurality of carbon nanotubes may have a length greater than 10 cm. The distance between two adjacent ultra-long carbon nanotubes in the carbon nanotube film is less than 5 micrometers, and the adjacent two super-long carbon nanotubes are closely connected by van der Waals force. The structure of the long carbon nanotube film and the preparation method thereof are described in Taiwan Patent Application No. 97107078, filed on Feb. 29, 2008.

It can be understood that the above-mentioned carbon nanotube film, ribbon carbon nanotube film or long carbon nanotube film are all self-supporting structures, which can be self-supported without substrate support. When the carbon nanotube film, the ribbon carbon nanotube film or the long carbon nanotube film are plural, they can be coplanar and have no gap laying or/and lamination to prepare nanometers of different areas and thicknesses. Carbon tube structure. In a nanocarbon tube structure composed of a plurality of mutually stacked carbon nanotube membranes, the arrangement of the carbon nanotubes in the adjacent two carbon nanotube membranes is the same.

The nanocarbon line-like structure includes at least one nanocarbon line. When the nanocarbon line-like structure comprises a plurality of nanocarbon pipelines, the plurality of nanocarbon pipelines may be parallel to each other to form a bundle structure or twisted to each other to form a stranded structure. The nanocarbon line can be a non-twisted nano carbon line or a twisted nano carbon line. The nanocarbon line-like structure may be single or multiple. Referring to FIG. 5, when it is a single root, the single carbon carbon pipeline-like structure can be bent into a film-like structure in a plane, and the carbon-carbon pipeline structure is other than the bent portion. The portions may be considered side by side and arranged in parallel with each other; referring to FIG. 6, when there are a plurality of roots, the plurality of nanocarbon line-like structures may be coplanar and arranged in parallel or stacked in one direction and arranged in parallel in one direction.

The non-twisted nanocarbon pipeline includes a plurality of non-twisted nanometers along the nanometer Carbon nanotubes arranged in the longitudinal direction of the carbon line. Specifically, the non-twisted nanocarbon pipeline includes a plurality of carbon nanotube segments, and the plurality of carbon nanotube segments are connected end to end by Van der Waals force, and each of the carbon nanotube segments includes a plurality of parallel and pass through each other Devalli is closely integrated with the carbon nanotubes. The carbon nanotube segments have any length, thickness, uniformity, and shape. The non-twisted nano carbon pipeline has an unlimited length and a diameter of 0.5 nm to 100 μm. The non-twisted nano carbon pipeline is obtained by treating a carbon nanotube film by an organic solvent. Specifically, the organic solvent is used to impregnate the entire surface of the carbon nanotube film, and under the action of the surface tension generated by the volatilization of the volatile organic solvent, the plurality of nanocarbons parallel to each other in the carbon nanotube film is parallel The tube is tightly coupled by van der Waals force, thereby shrinking the carbon nanotube film into a non-twisted nano carbon line. The organic solvent is a volatile organic solvent such as ethanol, methanol, acetone, dichloroethane or chloroform, and ethanol is used in this embodiment. The non-twisted nanocarbon line treated by the organic solvent has a smaller specific surface area and a lower viscosity than the carbon nanotube film which is not treated with the organic solvent.

The twisted nanocarbon pipeline includes a plurality of carbon nanotubes axially helically arranged around the twisted nanocarbon pipeline and extending along one end of the line to the other end. Specifically, the twisted nanocarbon pipeline includes a plurality of carbon nanotube segments, and the plurality of carbon nanotube segments are connected end to end by Van der Waals force, and each of the carbon nanotube segments includes a plurality of parallel and pass through each other Devalli is closely integrated with the carbon nanotubes. The carbon nanotube segments have any length, thickness, uniformity, and shape. The twisted nano carbon line is not limited in length and has a diameter of 0.5 nm to 100 μm. The twisted nanocarbon pipeline is configured to twist the ends of the carbon nanotube film in opposite directions by a mechanical force obtain. Further, the twisted nanocarbon line can be treated with a volatile organic solvent. Under the action of the surface tension generated by the volatilization of the volatile organic solvent, the adjacent carbon nanotubes in the twisted nanocarbon pipeline after treatment are tightly bonded by van der Waals force, so that the specific surface area of the twisted nanocarbon pipeline Decrease, increase in density and strength.

The nanocarbon line-like structure and its preparation method can be found in Taiwan Patent No. I303239, published on November 21, 2008 by Fan Shoushan et al., and Taiwan Patent Application No. 200724486, published on July 1, 2007. .

The nanocarbon line-like structure has a large strength, thereby improving the service life and stability of the electromagnetic wave polarization direction detecting device 10.

If the carbon nanotube structure is a combination of a carbon nanotube film or a nanocarbon line-like structure, the carbon nanotubes and the nanocarbon line-like structures in the carbon nanotube film are arranged in the same direction.

It can be understood that the above-mentioned carbon nanotube structures each include a plurality of carbon nanotubes, nanocarbon line-like structures or a combination thereof which are arranged substantially in parallel in the same direction.

Since the absorption of electromagnetic waves by the carbon nanotubes is close to an absolute black body, the carbon nanotubes have a uniform absorption characteristic for electromagnetic waves of various wavelengths, that is, the carbon nanotube structure 14 can absorb different wavelength ranges of infrared rays, visible rays, ultraviolet rays, and the like. Electromagnetic waves. Further, the carbon nanotubes rise in temperature after absorbing the energy of the electromagnetic waves. Using the theory of black body radiation, when the energy of the electromagnetic wave is high, such as laser radiation to the carbon nanotubes, the temperature of the carbon nanotubes can rise to a higher temperature and radiate visible light that can be observed by the human eye. . In this embodiment, the carbon nanotube structure 14 emits visible light when the temperature ranges from 800K to 2400K. And because of the difference in temperature, the wavelength of visible light emitted by the carbon nanotube structure 14 is also different, so that the color that appears is also changed accordingly. According to the color temperature effect, when the temperature of the carbon nanotube structure 14 rises from 800K to about 2400K, the color of visible light changes from dark red to red, from red to orange, from orange to yellow, and then Yellow turns white. It can be seen that as the temperature of the carbon nanotube structure 14 increases, the color of the visible light gradually changes from a warm color to a cool color, that is, the spectral radiation intensity gradually increases. Therefore, by observing the color of visible light emitted by the carbon nanotube structure 14, the temperature range of the carbon nanotube structure 14 can be derived. Referring to FIG. 7, the relationship between the incident power of the electromagnetic wave and the radiation density of the visible light radiated by the carbon nanotube structure 14 is shown. The ordinate in the figure is the optical radiation density of the visible light radiated by the carbon nanotube structure 14. The abscissa is the incident power of the electromagnetic wave. It can be seen that the relationship between the two is linear, wherein the optical radiation density can be expressed by σT ⁴ , where σ is the Stephen Boltzmann constant and T is the carbon nanotube structure 14 The temperature. According to the linear relationship, the stronger the absorption of the incident electromagnetic wave by the carbon nanotube structure 14 is, the higher the temperature is, the stronger the visible light is radiated. In addition, in this embodiment, since the carbon nanotube has a small heat capacity and a large heat dissipation area, the response speed to light is also fast, and the response speed is between 5 milliseconds and 200 milliseconds.

In addition, the thickness of the carbon nanotube structure 14 is not limited. When the thickness thereof is thin, it absorbs the incident electromagnetic wave and then rapidly heats up, and the response speed is fast, when the thickness of the carbon nanotube structure 14 is thick. When it is stronger However, compared with the thinner carbon nanotube structure, the heat exchange rate with the surrounding gas medium is slower, thereby affecting the response speed of the carbon nanotube structure 14. Preferably, the carbon nanotube structure 14 has a thickness of about 0.5 nm to 1 mm. In this embodiment, the carbon nanotube structure 14 is a single-layer carbon nanotube film.

The shape of the vacuum chamber 12 is not limited, and has an incident window 122 and a viewing window 124. The entrance window 122 is opposite and spaced from the carbon nanotube structure 14 to ensure that the electromagnetic waves can all pass through the entrance window 122 and be incident on the surface of the carbon nanotube structure 14, and the observation window 124 can The surface of the carbon nanotube structure 14 opposite the entrance window 122 is observed by the human eye.

The material of the incident window 122 is selected from a material that can transmit electromagnetic waves, and the material is also selected according to the wavelength of the incident electromagnetic wave. If the electromagnetic wave is visible light or ultraviolet light, the material may be quartz, and if the electromagnetic wave is infrared, the The material can be selected from gallium arsenide.

The material of the observation window 124 is a material that can transmit visible light, such as quartz.

In addition, the electromagnetic wave polarization direction detecting device 10 may further include a carrying device 16 disposed in the vacuum chamber 12 for carrying the carbon nanotube structure 14 while the carrying device 16 is also Rotating in a plane causes the carbon nanotube structure 14 to rotate accordingly. The shape of the carrying device 16 is not limited. Specifically, the carrying device 16 may be a flat or curved structure and has a surface. At this time, the carbon nanotube structure 14 is directly disposed and attached to the surface of the carrier device 16. Since the carbon nanotube structure 14 is entirely supported by the carrier device 16, the carbon nanotube structure 14 can withstand high-intensity electromagnetic wave input. another The carrier device 16 can also be a frame structure, a rod structure or an irregular shape structure. At this time, since the carbon nanotube structure 14 is a self-supporting structure, the carbon nanotube structure 14 is partially in contact with the carrier device 16, and the remaining portion is suspended. This arrangement can make the carbon nanotube structure 14 not absorb heat better by the influence of the carrying device 14, and the temperature changes more quickly, so when it emits light, the color or intensity of visible light emitted according to its own temperature. The speed of change is also getting faster.

The material of the carrying device 16 is not limited and may be a hard material such as diamond, glass or quartz. In addition, the carrying device 16 can also be a flexible material such as plastic or resin. Preferably, the material of the carrier device 16 should have better thermal insulation properties, thereby preventing the heat generated by the carbon nanotube structure 14 from being excessively absorbed by the carrier device 16, thereby affecting the temperature change of the carbon nanotube structure 14. .

Step 2: An electromagnetic wave source 20 is provided to emit a polarized electromagnetic wave 22 and incident on the surface of the carbon nanotube structure 14, and the carbon nanotube structure 14 emits light by absorbing the electromagnetic wave 22.

The electromagnetic wave emitting source 20 and the electromagnetic wave polarization direction detecting device 10 together constitute an electromagnetic wave polarization direction detecting system 30 which is disposed opposite to and spaced apart from the electromagnetic wave polarization direction detecting device 10 so as to be generated from the electromagnetic wave emitting source 20. The electromagnetic wave 22 can be transmitted to the surface of the carbon nanotube structure 14 through the incident window 122 of the electromagnetic wave polarization direction detecting device 10. Preferably, the electromagnetic wave 22 is directed substantially perpendicularly to the carbon nanotube structure 14 inside the electromagnetic wave polarization direction detecting device 10. When the electromagnetic wave emitting source 20 is spaced apart from the electromagnetic wave polarization direction detecting device 10, the electromagnetic wave 22 emitted from the electromagnetic wave emitting source 20 can be further passed. An optical fiber is transmitted to the surface of the carbon nanotube structure 14 of the electromagnetic wave polarization direction detecting device 10.

The frequency range of the electromagnetic wave 22 emitted by the electromagnetic wave source 20 includes radio waves, infrared rays, visible rays, ultraviolet rays, microwaves, X-rays, gamma rays, and the like. Preferably, the electromagnetic wave source 20 is an optical signal source, and the emitted electromagnetic wave 22 can be an optical signal, and the wavelength of the optical signal includes various light waves from ultraviolet to far infrared wavelength. The electromagnetic wave has an intensity ranging from 50 mW/mm 2 to 5000 mW/mm 2 . It can be understood that the intensity of the electromagnetic wave 22 is not too weak, and when the intensity is less than 50 mW/mm 2 , the carbon nanotube structure 14 cannot be heated to emit light, so that the carbon nanotube structure 14 reaches the temperature of the light emission. The electromagnetic wave polarization direction detecting device 10 may further include a focusing device 18 disposed opposite to the incident window 122 of the electromagnetic wave polarization direction detecting device 10, and the electromagnetic wave 22 may be focused and then irradiated to the nanocarbon. The surface of the tube structure 14.

In addition, the more the carbon nanotube structure 14 absorbs the electromagnetic wave 22, the higher the temperature, the color of the visible light will be correspondingly colder. Conversely, the color of visible light emitted by the carbon nanotube structure 14 can determine the nano carbon at this time. The temperature of the tube structure 14 is such that the absorption of the electromagnetic wave 22 by the carbon nanotube structure 14 at this time can be further advanced.

Further, in order to quantitatively measure the intensity of visible light emitted by the carbon nanotube structure 14, the electromagnetic wave polarization direction detecting device 10 may further include a spectrophotometer 19 disposed near the observation window 124 through the splitting light. The photometer 19 can quantitatively measure the intensity of visible light emitted by the carbon nanotube structure 14, and can determine the intensity of the absorbed electromagnetic wave 22 according to the intensity of the visible light emitted by the carbon nanotube structure 14.

Step 3: Rotating the carbon nanotube structure 14 to change the angle between the length direction of the carbon nanotubes in the carbon nanotube structure 14 and the polarization direction of the electromagnetic wave 22, and according to the angle change, the nai The carbon nanotube structure 14 emits a change in visible light to determine the polarization direction of the electromagnetic wave 22.

In this step, the carbon nanotube structure 14 is rotated in a plane substantially perpendicular to the incident direction of the electromagnetic wave, that is, the axis of the rotation is substantially perpendicular to the surface of the carbon nanotube structure 14, in order to realize the rotation of the carbon nanotube structure 14. The carbon nanotube structure 14 disposed on the carrier device 16 can be rotated correspondingly by rotating the carrier device 16. When the carbon nanotube structure 14 is rotated until the length direction of the carbon nanotube extends parallel to the polarization direction of the electromagnetic wave 22, the carbon nanotube structure 14 absorbs the electromagnetic wave 22 most strongly, and the temperature of the carbon nanotube structure 14 The highest, the carbon nanotube structure 14 emits the highest visible light radiation intensity, correspondingly the color of the visible light is the coldest; when the carbon nanotube structure 14 is rotated until the length of the carbon nanotube extends in a direction perpendicular to the polarization direction, the nano The carbon nanotube structure 14 has the weakest absorption of the electromagnetic wave 22, and the temperature of the carbon nanotube structure 14 is the lowest, and the radiation intensity of the visible light is the lowest, and accordingly the color of the visible light is the warmest color, since the nanometer at this time The temperature of the carbon tube structure 14 is different from the above-mentioned temperature at the position where the length direction of the carbon nanotube is parallel to the polarization direction of the electromagnetic wave 22, so the color thereof is also the same as the above-mentioned direction in the extension of the length of the carbon nanotube and the electromagnetic wave 22 The positions where the polarization directions are parallel are different when the light is irradiated. Therefore, by rotating the carbon nanotube structure 14, the polarization direction of the electromagnetic wave 22 can be judged by the color change of visible light. Specifically, in the process of changing the length direction of the carbon nanotubes in the carbon nanotube structure 14 and the polarization direction of the electromagnetic wave 22 from 0 ° C to 90 ° C, the carbon nanotubes The temperature of the structure changes from high to low, and the intensity of visible light changes from high to low, and the color gradually changes from cool to warm. That is, when the nano-carbon tube structure 14 emits visible light with the strongest radiation intensity and the color is the coldest color, the arrangement direction of the carbon nanotubes in the carbon nanotube structure 14 is the polarization direction of the electromagnetic wave 22.

Referring to FIG. 8 together, in the embodiment, a spectrophotometer 19 is used to quantitatively measure the carbon nanoparticle in the carbon nanotube structure 14 when the angle between the arrangement direction of the carbon nanotubes and the polarization direction of the electromagnetic wave 22 is changed. The tube structure 14 emits a relationship between the spectral radiation density of visible light and the angle between the arrangement direction of the carbon nanotubes and the polarization direction of the electromagnetic wave 22, wherein the optical radiation density can be expressed by σT ⁴ , where σ is the Stephen-Boltzmann constant , T is the temperature of the carbon nanotube structure 14. In the electromagnetic wave polarization direction detecting device 10, the carbon nanotube structure 14 is a single-layer carbon nanotube film, and the electromagnetic wave 22 is a focused infrared ray, and the carbon nanotube film absorbs the focused Infrared light. It can be seen from Fig. 8 that when the arrangement direction of the carbon nanotubes is parallel to the polarization direction of the electromagnetic wave, the spectral density of visible light emitted by the carbon nanotube film is the largest, that is, the intensity of the visible light is the highest, when the carbon nanotubes are used. When the alignment direction is perpendicular to the polarization direction of the electromagnetic wave, the spectral density of visible light emitted by the carbon nanotube film is the smallest, that is, the intensity of the visible light is the weakest. It can be seen that when the arrangement direction of the carbon nanotubes is parallel to the polarization direction of the electromagnetic wave, the carbon nanotube structure 14 absorbs the electromagnetic waves most strongly and has the highest temperature.

The electromagnetic wave detecting method provided in this embodiment has the following advantages: the method for detecting the polarization direction of the electromagnetic wave only needs to make the angle between the extending direction of the length of the carbon nanotube in the carbon nanotube structure and the polarization direction of the electromagnetic wave occur. Change, and in the process of change, by directly observing the color change of visible light emitted by the carbon nanotube structure, or by measuring the change of the intensity of the visible light by a measuring device, the polarization direction of the incident electromagnetic wave can be determined, and the method is simple and intuitive; The carbon nanotube structure is composed of only a plurality of carbon nanotubes, and has a simple structure, which is advantageous for reducing the manufacturing cost of the electromagnetic wave polarization direction detecting device and the cost of applying the device for detecting; since the carbon nanotube structure is a self The support structure has high strength and long service life; since the carbon nanotube structure in the electromagnetic wave polarization direction detecting device has uniform absorption characteristics for electromagnetic waves of respective wavelengths, the electromagnetic wave polarization direction detecting device can be used for detecting The polarization direction of electromagnetic waves of various wavelengths.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧Electromagnetic wave polarization direction detecting device

12‧‧‧ Vacuum chamber

122‧‧‧Injection window

124‧‧‧ observation window

14‧‧‧Nano Carbon Tube Structure

143‧‧‧Nano carbon nanotube fragments

145‧‧・Nano carbon tube

16‧‧‧ Carrying device

18‧‧‧ Focusing device

19‧‧‧Spectrophotometer

20‧‧‧Electromagnetic wave source

22‧‧‧Electromagnetic waves

30‧‧‧Electromagnetic polarization direction detection system

1 is a schematic structural view of an electromagnetic wave polarization direction detecting system according to an embodiment of the present invention.

2 is a flow chart of a method for detecting polarization direction of electromagnetic waves according to an embodiment of the present invention.

FIG. 3 is a partially enlarged schematic structural view of a carbon nanotube film for detecting a polarization direction of an electromagnetic wave in an electromagnetic wave polarization direction detecting device according to an embodiment of the present invention.

4 is used in the electromagnetic wave polarization direction detecting device provided by the embodiment of the present invention. Scanning electron micrograph of a carbon nanotube film for detecting the polarization direction of electromagnetic waves.

FIG. 5 is a schematic diagram showing the orderly bending of a nanocarbon line-like structure for detecting the polarization direction of electromagnetic waves in a plane in the electromagnetic wave polarization direction detecting device according to the embodiment of the present invention.

FIG. 6 is a schematic diagram showing a plurality of nanocarbon line-like structures for detecting polarization directions of electromagnetic waves arranged in parallel in a plane in an electromagnetic wave polarization direction detecting device according to an embodiment of the present invention.

FIG. 7 is a graph showing the relationship between the spectral radiation density of visible light emitted by the carbon nanotube structure and the incident electromagnetic wave power provided by the embodiment of the present invention.

FIG. 8 is a graph showing the relationship between the spectral radiation density of visible light emitted by the carbon nanotube structure provided by the embodiment of the present invention and the angle between the polarization direction of the electromagnetic wave and the length direction of the carbon nanotube.

10‧‧‧Electromagnetic wave polarization direction detecting device

12‧‧‧ Vacuum chamber

122‧‧‧Injection window

124‧‧‧ observation window

14‧‧‧Nano Carbon Tube Structure

16‧‧‧ Carrying device

18‧‧‧ Focusing device

19‧‧‧Spectrophotometer

20‧‧‧Electromagnetic wave source

22‧‧‧Electromagnetic waves

30‧‧‧Electromagnetic polarization direction detection system

Claims (16)

A method for detecting polarization direction of an electromagnetic wave, comprising the steps of: placing a carbon nanotube structure in a vacuum environment, the carbon nanotube structure comprising a plurality of carbon nanotubes arranged in the same direction; providing an electromagnetic wave emitting source, Transmitting a polarized electromagnetic wave and causing it to be substantially perpendicularly incident on the surface of the carbon nanotube structure, the carbon nanotube structure absorbing the electromagnetic wave and emitting light; rotating the nanometer in a plane substantially perpendicular to an incident direction of the electromagnetic wave a carbon tube structure, determining a polarization direction of the electromagnetic wave according to a change in intensity or color change of visible light of the carbon nanotube structure; and determining a polarization direction of the electromagnetic wave according to a change in intensity of visible light emitted by the carbon nanotube structure The method comprises: quantitatively measuring the intensity change of the visible light emitted by the carbon nanotube structure by using a measuring device, and extending the length of the carbon nanotube in the carbon nanotube structure when the intensity of the visible light is maximum; The polarization direction of the electromagnetic wave, when the intensity of the visible light emitted by the carbon nanotube structure is the smallest, the nano tube in the carbon nanotube structure The length extending direction of the tube is perpendicular to the polarization direction of the electromagnetic wave; and the step of determining the polarization direction of the electromagnetic wave according to the color change of the visible light emitted by the carbon nanotube structure comprises: when the carbon nanotube structure emits the color of visible light to be the coolest color The length of the carbon nanotube in the carbon nanotube structure extends in the direction of polarization of the electromagnetic wave. When the color of the carbon nanotube structure emits the color of the visible light, the length of the carbon nanotube in the carbon nanotube structure The extending direction is perpendicular to the polarization direction of the electromagnetic wave. The method for detecting polarization direction of electromagnetic waves according to claim 1, wherein the electromagnetic wave has an intensity ranging from 50 mW/mm 2 to 5000. Milliwatts per square millimeter. The electromagnetic wave polarization direction detecting method according to claim 1, wherein the electromagnetic wave is converged in advance before the electromagnetic wave is incident on the surface of the carbon nanotube structure. An electromagnetic wave polarization direction detecting device comprises: a vacuum chamber having an incident window and an observation window; and the improvement is that the electromagnetic wave polarization direction detecting device further comprises a carbon nanotube structure, the carbon nanotube The structure comprises a plurality of carbon nanotubes arranged in the same direction, the carbon nanotube structure is disposed in the vacuum chamber, the incident window is opposite to and spaced apart from the carbon nanotube structure, and the electromagnetic wave to be tested passes through the incident window Injected onto the surface of the carbon nanotube structure. The electromagnetic wave polarization direction detecting device according to claim 4, wherein the carbon nanotube structure comprises at least one carbon nanotube film, at least one nano carbon line structure, or a combination thereof. The electromagnetic wave polarization direction detecting device according to claim 5, wherein the carbon nanotube film comprises a plurality of carbon nanotubes substantially parallel to each other and substantially parallel to a surface of the carbon nanotube film. The electromagnetic wave polarization direction detecting device according to claim 5, wherein the carbon nanotube film comprises a plurality of carbon nanotubes which are connected end to end by van der Waals force and arranged in a preferred orientation in the same direction. The electromagnetic wave polarization direction detecting device according to claim 5, wherein the carbon nanotube structure comprises a plurality of carbon nanotube films, and the plurality of carbon nanotube films are coplanar and have no gaps to be laid or laminated. layout. The electromagnetic wave polarization direction detecting device according to claim 5, wherein the carbon nanotube structure comprises a nano carbon line-like structure, and the one nano carbon line structure is sequentially bent in a plane. Membrane knot Structure. The electromagnetic wave polarization direction detecting device according to claim 5, wherein the carbon nanotube structure comprises a plurality of nano carbon line-like structures, and the plurality of nano carbon line-like structures are substantially parallel and coplanar . The electromagnetic wave polarization direction detecting device according to claim 5, wherein the nanocarbon line-like structure comprises at least one non-twisted nano carbon line, at least one twisted nano carbon line, or a combination thereof. The electromagnetic wave polarization direction detecting device according to claim 11, wherein the non-twisted nanocarbon pipeline includes a plurality of carbon nanotubes arranged in parallel along a length direction of the non-twisted nanocarbon pipeline, The twisted nanocarbon pipeline includes a plurality of carbon nanotubes arranged spirally along the length of the twisted nanocarbon line. The electromagnetic wave polarization direction detecting device according to claim 4, wherein the carbon nanotube structure is at least partially suspended. The electromagnetic wave polarization direction detecting device according to claim 4, wherein the electromagnetic wave polarization direction detecting device further comprises a carrying device, wherein the carbon nanotube structure is carried by the carrying device, and the carrying device is Rotate in a plane perpendicular to the direction of the incident electromagnetic wave. The electromagnetic wave polarization direction detecting device according to claim 4, wherein the electromagnetic wave polarization direction detecting device further comprises a focusing device, the focusing device is opposite to the carbon nanotube structure and spaced apart for use in The incident electromagnetic wave is concentrated. The electromagnetic wave polarization direction detecting device according to claim 4, wherein the electromagnetic wave polarization direction detecting device further comprises a spectrophotometer, the spectrophotometer is disposed opposite to the observation window and is used for measuring the nai The carbon nanotube structure emits the intensity of visible light.