WO2017140145A1

WO2017140145A1 - High-resolution temperature sensor on the basis of built-in liquid capsule and fixed wavelength

Info

Publication number: WO2017140145A1
Application number: PCT/CN2016/106682
Authority: WO
Inventors: 欧阳征标; 陈治良
Original assignee: 深圳大学
Priority date: 2016-02-15
Filing date: 2016-11-21
Publication date: 2017-08-24
Also published as: CN105606250A; CN105606250B

Abstract

A high-resolution temperature sensor based on a built-in liquid capsule and a fixed wavelength consists of a liquid capsule (2), a metal block (3), a vertical waveguide (4), a horizontal waveguide (5), two metallic films (1, 6) and horizontally spreading signal light (200), wherein the liquid capsule (2) and the vertical waveguide (4) are connected, the metal block (3) is arranged in the vertical waveguide (4) and can move, the vertical waveguide (4) and the horizontal waveguide (5) are connected, and the signal light (200) employs a fixed wavelength. The high-resolution temperature sensor has advantages of compact structure, small size and high resolution and can be integrated conveniently.

Description

High resolution temperature sensor based on built-in sac and fixed wavelength

Technical field

The invention relates to a high-resolution, nano-scale temperature sensor, in particular to a high-sensitivity temperature sensor based on built-in liquid capsule and single-wavelength laser detection.

Background technique

Temperature sensors are one of the most widely used sensors in the world. From the thermometers in our lives, thermometers to large instruments and temperature control devices on integrated circuits, temperature sensors are everywhere. Traditional temperature sensors, such as thermal resistors, platinum resistors, and bimetal switches, have their own advantages, but are no longer suitable for use in miniature and high precision products. Semiconductor temperature sensors have high sensitivity, high resolution, low power consumption, and high anti-interference ability, making them widely used in semiconductor integrated circuits.

Waveguides based on surface plasmons can break through the limits of diffraction limits and achieve nanoscale optical information processing and transmission. The surface plasmon is a surface electromagnetic wave propagating on the metal surface formed by the free electron coupling of the electromagnetic wave and the metal surface when the electromagnetic wave is incident on the interface between the metal and the medium.

At present, based on the properties of surface plasmons, devices based on surface plasmon structures, such as filters, circulators, logic gates, optical switches, etc., have been proposed. These devices are relatively simple in structure and are very convenient for optical path integration.

The sensitivity of the temperature sensor in the prior art is 70 pm / ° C or -0.65 nm / ° C, although the temperature sensor is small, but the sensitivity or resolution is not high.

Summary of the invention

The object of the present invention is to overcome the deficiencies of the existing temperature sensor resolution and to provide a high resolution temperature sensor that facilitates the integration of the MIM structure.

The object of the present invention is achieved by the following technical solutions.

The invention is based on a built-in sac and a fixed wavelength high resolution temperature sensor consisting of an internal sac, a metal block, a vertical waveguide, a horizontal waveguide, two metal films and a horizontally propagating signal light; The signal light is of a fixed wavelength; the liquid capsule is connected to the vertical waveguide, the metal block is disposed within the vertical waveguide, and is movable; the vertical waveguide is connected to the horizontal waveguide; and the signal light is at a fixed wavelength.

The substance in the sac is a substance having a high coefficient of thermal expansion;

The substance having a high expansion coefficient is alcohol or mercury.

The shape of the cross section of the sac is rectangular, circular, polygonal, elliptical or irregular.

The metal is gold or silver.

The metal is silver.

The horizontal waveguide and the vertical waveguide are waveguides of a MIM structure.

The medium within the horizontal waveguide is air.

The signal light is a single wavelength laser having a wavelength of 792 nm.

The movable silver block is fixed at a position of 116 nm.

The beneficial effects of the present invention compared to the prior art are:

1. It has compact structure, small size and is very easy to integrate.

2. The resolution is high, the average temperature resolution reaches 0.0083 °C on average, and the highest resolution is 0.005 °C.

DRAWINGS

1 is a two-dimensional structural diagram of a first embodiment of a high resolution temperature sensor of the present invention.

In the figure: metal film 1 built-in sac 2 metal block 3 vertical waveguide 4 horizontal waveguide 5 metal film 6 horizontally propagated signal light 200

2 is a schematic view of the three-dimensional structure shown in FIG. 1.

3 is a schematic view showing the two-dimensional structure of a second embodiment of the high resolution temperature sensor of the present invention.

4 is a schematic view of the three-dimensional structure shown in FIG.

Figure 5 is a transmission spectrum diagram of signal light of different wavelengths.

Figure 6 is an average of the intervals of transmittance for different wavelengths.

Fig. 7 is a graph showing the derivative of the transmittance corresponding to temperature.

detailed description

The present invention will be further described below in conjunction with the drawings and embodiments.

As shown in Figures 1 and 2 (the package medium above the structure is omitted in Figure 2), the present invention is based on a built-in sac and a fixed-wavelength high-resolution temperature sensor consisting of a metal film 1, a built-in sac 2, and a metal block. 3. A vertical waveguide 4, a horizontal waveguide 5, metal films 1, 6 (metal film not etched) and a horizontally propagating signal light 200 (the surface of the waveguide forms a surface plasmon); the signal light is fixed Wavelength; the sac 2 is connected to the vertical waveguide 4, and the sac 2 (temperature sensitive cavity) has a circular cavity with a radius of R, a cross-sectional area of 502655 nm ² and a thickness of 1 μm, and the substance in the sac 2 is a specific heat capacity. Lower, high thermal expansion coefficient, high expansion coefficient material is alcohol or mercury, preferably alcohol; metal is gold or silver, preferably silver, metal film thickness (hereinafter referred to as h ₁ ) using 100nm or more The value range is preferably 100 nm thick; the thickness of the liquid capsule 2 is larger than the thickness h _{1 of the} silver film; the metal block 3 is disposed in the vertical waveguide 4 and can be moved, and the length m of the moving metal block 3 is 80 nm-150 nm. Range, best at 125nm length, removable The distance s of the block 3 from the horizontal waveguide 5 is in the range of 0 nm to 200 nm, and is determined by the position of the metal block 3, which is gold or silver, preferably silver; the vertical waveguide 4 and the horizontal waveguide 5 are connected; The vertical waveguide 4 and the horizontal waveguide 5 are waveguides of the MIM structure, that is, the MIM waveguide is a metal-insulator-metal structure; the insulator is made of a non-conductive transparent material; the non-conductive transparent material is air, silicon dioxide, or silicon; The waveguide 4 and the horizontal waveguide 5 are connected; the width b of the vertical waveguide 4 is in the range of 30 nm to 60 nm, and the width is preferably 35 nm, and the length M of the vertical waveguide 4 is 200 nm or more, and the length is preferably 300 nm; the vertical waveguide 4 The distance a from the left edge to the left edge of the metal film 6 is in the range of 350 nm to 450 nm, preferably 400 nm. The vertical waveguide 4 is located at the upper end of the horizontal waveguide 5; the width d of the horizontal waveguide 5 is in the range of 30 nm to 100 nm, and the width is preferably 50 nm, and the medium in the horizontal waveguide 5 is air; the lower edge of the horizontal waveguide 5 is away from the metal film 6 The distance c of the edge uses a range of values greater than 150 nm.

The present invention changes the volume of the alcohol by a change in temperature, causing it to expand to push the movable metal block 3 to move toward the horizontal waveguide 5 to change the length of the air segment in the vertical waveguide 4, and the movable metal block 3 moves downward to make it horizontal. The distance of the waveguide 5 changes, and the transmittance of the signal light changes accordingly; since the movable metal block 3 moves downward, it is controlled by temperature. Therefore, the change of temperature affects the change of the transmittance of the signal light, and the change of the temperature information can be detected according to the change of the transmittance; the characteristic of the transmittance can correspond to the temperature one by one, that is, the temperature can be known from the characteristics of the transmittance Variety. When the temperature drops back to the initial temperature, under the action of the external atmospheric pressure, the metal block 3 will return to the initial pressure balance position, which is convenient for the next detection.

The alcohol volume expansion coefficient in the sac 2 of the present invention is α _ethanol = 1.1 × 10 ^-3 / ° C, and the density is ρ = 0.7789 g / cm ³ at room temperature (20 ° C). Linear expansion coefficient of silver is _{^{α Ag = 19.5 × 10 -6 /}} ℃. Compared to the coefficient of expansion of alcohol, the expansion of silver is negligible at the same temperature change. In the present invention, the influence of temperature changes on the volume of silver is no longer considered. According to the volume of the sac and the cross-sectional area of the movable metal block, the relationship between the position change of the metal block and the temperature can be calculated, thereby defining a proportional coefficient σ indicating the moving distance of the metal block corresponding to the change of the unit temperature.

This formula can also be used as a measure of the temperature sensitivity of the structure. According to this formula, it can be concluded that the cross-sectional area of the circular absorption cavity and the width of the movable metal block have a relatively large influence on the positional change of the metal block, and comprehensively consider S=502655 nm ² and b=35 nm. Then σ = 157 nm / ° C, the result is the relationship between the amount of movement of the metal block and temperature.

As shown in Figures 3 and 4 (the package medium above the structure is omitted in Figure 4), the present invention is based on a built-in sac and a fixed-wavelength high-resolution temperature sensor consisting of a metal film 1, a built-in sac 2, and a metal block. 3. A vertical waveguide 4, a horizontal waveguide 5, a metal film 6 (

metal film

1, 6 not etched) and a horizontally propagating signal light 200 (the surface of the waveguide forms a surface plasmon); said signal The light adopts a fixed wavelength; the sac 2 is connected to the vertical waveguide 4, and the sac 2 (temperature sensitive cavity) has a cross-sectional area of a hexagonal cavity, a side length of r, a cross-sectional area of 502655 nm ² , and a thickness of 1 μm, which is sensitive to temperature. The material in the cavity has a lower specific heat capacity and is a substance with a high coefficient of thermal expansion. The substance in the liquid capsule 2 (temperature sensitive cavity) is a substance having a lower specific heat capacity and a high thermal expansion coefficient, and the high expansion coefficient substance is alcohol or mercury. It is preferable to use alcohol; the metal is gold or silver, preferably silver, the thickness of the metal film h ₁ is in the range of 100 nm or more, and the thickness is preferably 100 nm; the thickness of the liquid capsule 2 is larger than the thickness of the silver film h ₁ ; The metal block 3 is disposed in the vertical waveguide 4; To move, the length of the moving metal block 3 is in the range of 80 nm to 150 nm, and the length is preferably 125 nm. The distance s of the movable metal block 3 from the horizontal waveguide 5 is in the range of 0 nm to 200 nm, and the position of the metal block 3 is It is determined that the metal block 3 is gold or silver, preferably silver; the vertical waveguide 4 is connected to the horizontal waveguide 5; the horizontal waveguide 5 and the vertical waveguide 4 are waveguides of the MIM structure, that is, the MIM waveguide is a metal-insulator-metal structure The insulator is made of a non-conductive transparent material; the non-conductive transparent material is air, silicon dioxide, or silicon; the vertical waveguide 4 is located at the upper end of the horizontal waveguide 5; the medium in the horizontal waveguide 5 is air; and the vertical waveguide 4 has a width b of 30 nm. The value range of -60 nm is optimal with a width of 35 nm, and the length M of the vertical waveguide 4 is 200 nm or more, and the length of 300 nm is optimal; the distance a from the left edge of the vertical waveguide 4 to the left edge of the metal film 6 is 350 nm to 450 nm. The range of values is best at 400 nm. The width d of the horizontal waveguide 5 is in the range of 30 nm to 100 nm, and the width is preferably 50 nm. The medium in the horizontal waveguide 5 is air; the distance from the lower edge of the horizontal waveguide 5 to the edge of the metal film 6 is greater than 150 nm. range.

The present invention changes the volume of the alcohol by a change in temperature, causing it to expand to push the movable metal block 3 to move toward the horizontal waveguide 5 to change the length of the air segment in the vertical waveguide 4; since the movable metal block 3 moves downward due to temperature Control, so the change of temperature affects the change of the transmittance of the signal light, and the change of the temperature information can be detected according to the change of the transmittance; the characteristic of the transmittance can correspond to the temperature one by one, that is, the temperature can be known from the characteristics of the transmittance Variety. When the temperature drops back to the initial temperature, under the action of the external atmospheric pressure, the metal block 3 will return to the initial pressure balance position, which is convenient for the next detection.

The movable metal block 3 is moved downward to change the distance to the horizontal waveguide 4, and the transmittance of the signal light changes accordingly. As shown in Fig. 5, the transmittance of light of each wavelength of the wavelength of 700 nm to 1000 nm when the value of s is different in the structure of the present invention. The initial position of the silver block is the position at the initial temperature (for example, 20 ° C), and its value is s=160 nm; scanning with simulation software can obtain the transmittance of each wavelength of the horizontal waveguide 5 when the temperature changes are constant, and then let the corresponding wavelength The transmittance values are sequentially different, and then they are averaged in absolute value. Thus, the change value of the transmittance in each unit wavelength interval in the unit temperature interval can be obtained, and the result is shown in Fig. 6. The curve in the figure represents the average value of the intervals of the transmittances of the respective wavelengths at the scanning interval of 0.025 °C. Using the simulation software scanning, the transmittance of each wavelength of the horizontal waveguide 5 can be obtained when the temperature changes are certain, and then the transmittance values of the corresponding wavelengths are sequentially different and then the absolute values are summed and averaged, so that each temperature interval is fixed. The average of the differences in wavelength transmittance. From the figure, when the wavelength is 792 nm, the transmittance interval has a maximum value of 0.067207.

The horizontally propagated signal light 200 is a single wavelength laser, and the horizontal waveguide signal light is At a single source of 792 nm, the change in temperature affects the change in the transmittance of the signal light, and the change in temperature information can be detected based on the change in transmittance. The average resolution of the temperature sensor designed by this detection method is set to 0.0083 ° C by setting the transmittance change of the detector to a single wavelength transmittance of 2%. After the temperature sensor increases the volume of the sac 2, the movable metal block 3 is more sensitive to temperature. After the volume of the sac 2 is doubled, the resolution of the temperature sensor is also doubled to 0.00415 °C. As shown in FIG. 7, in the case where the incident signal light is 792 nm, the transmittance at different temperatures is scanned, and the scanning temperature interval is 0.01 ° C, so that the moving interval of the moving metal block 3 is 1.57 nm. The scan results are shown in the black dotted curve in Figure 7. Then the curve is differentiated to find dt/dT, which is the derivative curve of transmittance versus temperature. The curve obtained is shown in the black undoped curve in Fig. 7. When the image is processed, the position of the corresponding temperature point corresponding to the movable metal block 3 is also marked on the horizontal axis in order to find the position where the transmittance changes the most. According to the black no-point curve, it is possible to obtain the maximum transmittance change rate at the position of s=116 nm. According to the scanning interval, the temperature resolution of the temperature sensor at this position can be calculated as 0.005 ° C, which is the resolution of the temperature sensor at a fixed temperature point.

In practical applications, the measurement of the vicinity of a fixed temperature point allows the movable metal block 3 to be fixed at 116 nm, so that a high sensitivity or high resolution measurement at a fixed temperature point can be achieved.

Although the present invention has been described in terms of specific examples, various modifications will be apparent to those skilled in the art.

Claims

A high-resolution temperature sensor based on a built-in sac and fixed wavelength, characterized by an internal sac, a metal block, a vertical waveguide, a horizontal waveguide, two metal films, and a horizontally propagating signal light Composed; the liquid capsule is connected to the vertical waveguide, the metal block is disposed in a vertical waveguide, and is movable; the vertical waveguide is connected to a horizontal waveguide; and the signal light is at a fixed wavelength.
The high-resolution temperature sensor based on built-in sac and fixed wavelength according to claim 1, wherein the substance in the sac is a substance having a high coefficient of thermal expansion.
The high-resolution temperature sensor based on built-in sac and fixed wavelength according to claim 2, wherein the substance having a high expansion coefficient is alcohol or mercury.
The high-resolution temperature sensor based on built-in sac and fixed wavelength according to claim 1, wherein the shape of the sac cross section is rectangular, circular, polygonal, elliptical or irregular.
The high resolution temperature sensor based on built-in sac and fixed wavelength according to claim 1, wherein the metal is gold or silver.
A high resolution temperature sensor based on an internal sac and a fixed wavelength according to claim 5, wherein said metal is silver.
The high resolution temperature sensor based on built-in sac and fixed wavelength according to claim 1, wherein said horizontal waveguide and said vertical waveguide are waveguides of MIM structure.
The high resolution temperature sensor based on built-in sac and fixed wavelength according to claim 1, wherein the medium in said horizontal waveguide is air.
High-resolution temperature based on built-in sac and fixed wavelength according to claim The sensor is characterized in that the signal light is a single-wavelength laser and has a wavelength of 792 nm.
The high-resolution temperature sensor based on built-in sac and fixed wavelength according to claim 1, wherein the movable metal block has a fixed position of 116 nm.