Measurement method and measurement device

Abstract

A measurement method comprises a first step in which, in a state where a measurement unit (M) having at least a portion of an optical waveguide (12) and a micro optical resonator (14) which is optically coupled to said portion and through which at least some light propagating through the optical waveguide passes is disposed within a vapor layer formed by a liquid contained in an object, a process for causing the light to enter the optical waveguide and detecting the optical resonance frequency of the light emitted from the optical waveguide is performed a plurality of times. The measurement method furthermore includes a second step in which a change in the vapor density of the vapor layer is identified on the basis of an optical resonance frequency obtained through each of the plurality of instances of the process performed in the first step. Thus, a change in the vapor density of the vapor layer formed by the liquid contained in the object can be measured by the optical resonator.

Description

Measurement method and measuring device

[0001] The present invention relates to a measurement method and a measuring device.

[0002] A microresonator capable of detecting an external stimulus from a shift in the optical resonance frequency is known. A method for identifying the mechanical properties of an object using this microoptical resonator is also known (Patent Document 1 and Non-Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2019-113328

[0004] M. Asano, G. Zhang, T. Tawara, H. Yamaguchi, and H. Okamoto, “Near-field cavity optomechanical coupling in a compound semiconductor nanowire”, COMMUNICATIONS PHYSICS, (2020) 3:230.

[0005] In the above method, since the local effective refractive index change of the optical near-field is used, it is necessary to bring the microoptical resonator close to the object to be identified at an interval of about the optical wavelength of the light input to the optical resonator, and this position control is difficult.

[0006] The inventors of the present application have found that a change in the vapor density of a vapor layer (a change according to the position of the vapor density or a temporal change in the vapor density) caused by evaporation from an object containing a liquid (including an object consisting only of a liquid) can be measured by an optical resonator, and have found that the characteristics of the above liquid can be identified from the measurement results. The method of using the measurement result of the change in the vapor density of the vapor layer is not limited to the identification of the characteristics of the above liquid.

[0007] An object of the present invention is to measure a change in the vapor density of a vapor layer formed by a liquid contained in an object using an optical resonator.

[0008] The measurement method according to the present invention comprises a first step of placing a measurement unit, which has at least a portion of an optical waveguide and a minute optical resonator through which at least a portion of the light that is optically coupled with the at least portion and propagates through the optical waveguide, in a vapor layer formed by a liquid contained in an object, and then injecting the light into the optical waveguide and performing a process multiple times to detect the optical resonance frequency of the light emitted from the optical waveguide; and a second step of identifying a change in the vapor density of the vapor layer based on the optical resonance frequencies obtained from each of the multiple processes performed in the first step.

[0009] The measuring device according to the present invention comprises: a measuring unit having at least a portion of an optical waveguide and a minute optical resonator through which at least a portion of the light that is optically coupled with the at least portion and propagates through the optical waveguide passes; a driving mechanism for moving the measuring unit and an object relative to each other; and a processing unit that controls the driving mechanism to position the measuring unit in a vapor layer formed by a liquid contained in the object, and performs a process multiple times in which light is incident on the optical waveguide and the optical resonance frequency of the light emitted from the optical waveguide is detected, wherein the processing unit identifies a change in the vapor density of the vapor layer based on the optical resonance frequency obtained by each of the multiple processes.

[0010] With the above configuration, the change in vapor density of the vapor layer formed by the liquid contained in the object can be measured using an optical resonator.

[0011] Figure 1 is a diagram showing the configuration of a measuring device according to an embodiment of the present invention. Figure 2 is a diagram illustrating a measurement method using the measuring device according to an embodiment of the present invention. Figure 3 is a graph showing the frequency characteristics of the detected light. Figure 4 is a graph showing the relationship between the distance from the inspection table to the measurement unit and the optical resonance frequency. Figure 5 is a graph superimposed on the frequency characteristics of the detected light at each position when the measurement unit is moved. Figure 6 is a diagram showing the configuration of the main part of a modified measuring device. Figure 7 is a graph showing the relationship between the distance from the inspection table to the measurement unit and the optical resonance frequency. Figure 8 is a diagram showing the configuration of a modified measuring device. Figure 9 is a graph showing the relationship between the frequency that vibrates a droplet and the amplitude of the optical resonance frequency at that frequency. Figure 10 is a graph showing the relationship between the natural vibration frequency that can be determined from the amplitude of the optical resonance frequency and the size of the droplet. Figure 11 is a diagram showing the configuration of a modified measuring device. Figure 12 is a diagram showing the configuration of the main part of a modified measuring device.

[0012] Hereinafter, embodiments of the present invention and their modifications will be described with reference to the drawings.

[0013] (Outline of Measurement Method) The measurement method according to this embodiment measures the change in vapor density (or humidity; the same applies to vapor density hereinafter) of the liquid vapor layer formed by the liquid contained in an object. The object may be the liquid itself. In this case, the object may be a liquid droplet. The vapor layer is produced by the evaporation of the liquid. The vapor layer has a vapor density distribution that is dense near the interface with the object (especially the liquid) (saturated water vapor layer) and thins out as it moves away from the object. The change in vapor density includes a change over time and a change depending on the position of the vapor layer.

[0014] (Configuration of the measuring device) An example of a measuring device that can be used in the above measurement method will be described as measuring device 10. As shown in Figure 1, measuring device 10 comprises a support member 11, a tapered fiber 12, a support member 13, an optical resonator 14, fixing members 15A to 15C (collectively referred to as fixing member 15), a light source 16, a photodetector 17, a drive mechanism 18, and a processing unit (e.g., a processing circuit) 19. At least a portion of the optical resonator 14 and the tapered fiber 12 plays a particularly important role in measuring changes in vapor density. Hereinafter, these will also be referred to as the measuring unit M. The "part" of the tapered fiber 12 includes the portion that is optically coupled with the optical resonator 14.

[0015] The support member 11 supports elements 12 to 15. The support member 11 comprises a plate-shaped main body 11A and two arms 11B and 11C that extend forward from the main body 11A at a distance from each other in the left-right direction. Tapered fibers 12 are stretched across the arms 11B and 11C.

[0016] The tapered fiber 12 extends in the left-right direction and is an optical fiber having a taper that gradually widens from a small-diameter section 12A in the middle (especially in the center) toward both ends. The small-diameter section 12A is the thinnest part of the tapered fiber 12. The tapered fiber 12 is fixed at two points on either side of the center to arms 11B and 11C by fixing materials 15B and 15C such as ultraviolet-curing resin.

[0017] The support member 13 is supported by the support member 11. The support member 13 is rod-shaped and extends in the front-rear direction, and is fixed to the main body 11A of the support member 11 by a fixing material 15A such as ultraviolet curing resin. An optical resonator 14 is connected to the front end of the support member 13. The two may be formed integrally. For example, a microsphere with a diameter of 200 μm is formed at the tip of a silica optical fiber. The microsphere becomes the optical resonator 14, and the optical fiber becomes the support member 13. The support member 13 may be composed of a material other than an optical fiber. The optical resonator 14 is a micro-optical resonator. The optical resonator 14 is positioned in contact with or close to the small-diameter portion 12A of the tapered fiber 12. As a result, the optical resonator 14 is optically coupled with the small-diameter portion 12A. The spherical optical resonator 14 has whispering gallery modes.

[0018] A light source 16 is connected to the left end of the tapered fiber 12. Light from the light source 16 is incident on one end of the tapered fiber 12. A photodetector 17 is connected to the right end of the tapered fiber 12. The photodetector 17 detects the light that reaches the other end of the tapered fiber 12 and is emitted from that end. The photodetector 17 converts the detected light (hereinafter also referred to as detected light) into an electrical signal and inputs it to the processing unit 19. The frequency characteristics of the intensity (e.g., voltage) of the converted electrical signal match the frequency characteristics of the intensity of the detected light (e.g., the transmittance of the detected light relative to the light incident from one end).

[0019] The drive mechanism 18 moves elements 11 to 15 in the vertical direction. For example, the drive mechanism 18 includes, for example, a stage that holds a support member 11 and a drive device that drives this stage in the vertical direction. The drive mechanism 18 moves elements 11 to 15 so that the measuring section M, including the optical resonator 14, moves within the vapor layer V1 (Figure 2). For example, if the thickness of the vapor layer V1 is on the order of millimeters to micrometers, the drive mechanism 18 may be configured to move elements 11 to 15 by stepping motor drive. If the vapor layer V1 is even thinner, the drive mechanism 18 may be configured to move elements 11 to 15 by piezo drive.

[0020] The processing unit 19 includes, for example, at least one of the following: one or more processors (e.g., a CPU (Central Processing Unit)), one or more ASICs (Application Specific Integrated Circuits), and one or more FPGAs (Field-programmable Gate arrays). The processing unit 19 may have memory for storing various programs and data. The processing unit 19 is configured to control elements 16 to 18 (details will be described later).

[0021] (Measurement Method 1 Using a Measuring Device) A measurement method using the measuring device 10 will be described with reference to Figure 2. As shown in Figure 2, in this measurement, the change in vapor density (hereinafter also referred to as the vapor density distribution) according to the position of a droplet D1 dropped onto an inspection table S provided by the measuring device 10 within the vapor layer V1 (in Figure 2, only a portion of the vapor layer V1 separated by a dashed line is shown) is measured.

[0022] First, the operator performing the measurement operates the measuring device 10 via a user interface (not shown) or the like to move the measuring unit M (at least a part of the optical resonator 14 and tapered fiber 12) to its initial position before the measurement. The processing unit 19 controls the drive mechanism 18 based on the above operation to move the measuring unit M to its initial position. The initial position is within the vapor layer V1. The drive mechanism 18 only needs to move the relative positional relationship between the droplet D1 and the measuring unit M; for example, it may be configured to move the inspection table S.

[0023] Subsequently, the operator inputs a command to start the measurement to the measuring device 10 via a user interface (not shown). The processing unit 19 controls the light source 16 in response to the input command.

[0024] The light source 16, under the control of the processing unit 19, emits, for example, a 1550 nm laser beam to one end (left end) of the tapered fiber 12. The emitted laser beam propagates through the tapered fiber 12. Part or all of the propagating laser beam enters the optical resonator 14 from the small diameter portion 12A as near-field light. The light that enters the optical resonator 14 circulates along the spherical surface by repeatedly undergoing total internal reflection on the spherical surface of the optical resonator 14 in whispering gallery mode. The light that circulates along the spherical surface (hereinafter also referred to as circulating light) returns to the small diameter portion 12A of the tapered fiber 12 and propagates through the tapered fiber 12 to the other end (right end) together with the light that propagates through the tapered fiber 12 without passing through the optical resonator 14. Here, the circulating light propagates through the vapor layer V1 around the optical resonator 14 as near-field light during total internal reflection. This causes a phase shift in the circulating light. The amount of phase shift changes according to the refractive index of the surrounding vapor layer V1. In the propagation of light as described above, various optical interferences occur due to the phase shift. When only a portion of the laser light is incident on the optical resonator 14 from the small diameter portion 12A as near-field light, the optical interference includes interference between light that has passed through the optical resonator 14 and light that has not. In the optical interference, optical resonance occurs at a predetermined frequency. Therefore, as shown in Figure 3, the transmittance of a portion of the detected light that reaches the other end of the tapered fiber 12 and is detected by the photodetector 17 is lower than the intensity of the remaining light. The transmittance in Figure 3 is the ratio of the intensity of light at that frequency to the laser light incident on the tapered fiber 12. Transmittance can also be called the intensity of light. The frequency of the portion of light with low intensity, i.e., the optical resonance frequency, changes according to the degree of phase change, i.e., the refractive index of the vapor layer V1. The refractive index changes according to the vapor density. Therefore, by capturing the optical resonance frequency, the vapor density distribution corresponding to the position of the vapor layer V1 can be measured.

[0025] The processing unit 19 analyzes the frequency characteristics of the electrical signal representing the detected light from the photodetector 17 and performs a process to identify the optical resonance frequency.

[0026] Furthermore, the processing unit 19 repeatedly performs the following processes: controlling the movement mechanism 18 to move the measuring unit M upward away from the droplet D1, and analyzing the electrical signal from the photodetector 17, which represents the light emitted from the light source 16 and detected by the photodetector 17 after the movement.

[0027] Through the above processing, the processing unit 19 can obtain multiple optical resonance frequencies corresponding to the position of the measurement unit M, that is, the position of the vapor layer V1.

[0028] Here, assuming droplet D1 is pure water, Figure 4 shows the relationship between each position of the measurement unit M and the optical resonance frequency (experimental value) at that position. In the graph of Figure 4, the distance on the horizontal axis is the distance of the measurement unit M from the inspection table S, and is converted to a relative distance with the distance from the inspection table S to the initial position set to 1.0. The optical resonance frequency on the vertical axis of the graph of Figure 4 is converted to a relative value with the optical resonance frequency when the measurement unit M is in the initial position set to 1.0. As shown in Figure 4, it can be seen that the optical resonance frequency shifts to the lower side as the distance from the measurement unit M increases. Figure 5 is a superimposed graph of the frequency characteristics of the intensity (transmittance) of the detected light at each position of the measurement unit M. In Figure 5, the frequency on the horizontal axis is shown as the difference from the optical resonance frequency = 0 when the measurement unit M is in the initial position. As shown by the arrows in Figure 5, the optical resonance frequency decreases as the measurement unit M moves away from droplet D1. The dotted line in Figure 4 is a theoretical curve obtained by normalizing the vapor density distribution of the vapor layer V1, derived from the diffusion equation, to an appropriate value, and this curve shows good agreement with the experimental value. From the above, it can be seen that the vapor density of the vapor layer is correlated with the optical resonance frequency.

[0029] Based on the above, a table or function showing the relationship between optical resonance frequency and vapor density is derived in advance through experiments or other means and stored in the processing unit 19. The processing unit 19 uses the table or function to derive the vapor density at the optical resonance frequency obtained in the above process. The processing unit 19 derives the vapor density at each position of the measurement unit M, i.e., the vapor density distribution. This identifies the vapor density distribution of the vapor layer V1. With this identification, the measurement device 10 has measured the vapor density distribution using the light incident on the tapered fiber 12 as the measurement light. The processing unit 19 may output the vapor density distribution to an external device (e.g., a display device). The vapor density distribution changes depending on the physical properties of the droplet D1 (e.g., temperature, composition). In other words, the vapor density distribution indicates the physical properties of the droplet D1. Based on the vapor density distribution, the processing unit 19 may identify the physical properties of the droplet D1 through a predetermined process and output the identification result. If the physical properties of droplet D1 correspond one-to-one with the vapor density distribution, the processing unit 19 may directly derive the physical properties of droplet D1 as a type of vapor density distribution based on the optical resonance frequency.

[0030] The frequency of the laser light incident on the tapered fiber 12 is set to the attenuated portion centered around the optical resonance frequency, for example, if Figure 3 shows the frequency characteristics of the detected light when the measurement unit M is placed in its initial position.

[0031] As described above, according to this embodiment, by utilizing the correlation between the optical resonance frequency and the change in vapor density according to the position (vapor density distribution), the measurement unit M can measure the change in vapor density (vapor density distribution) of the vapor layer V1 generated by evaporation from a liquid (here, a liquid droplet D1, but not limited to a liquid droplet).

[0032] Furthermore, since the measurement unit M (especially the optical resonator 14) only needs to be positioned within the vapor layer V1, positional control on the order of the wavelength of light, as required for identifying the physical properties of an object using conventional near-field light, becomes unnecessary. This is because the vapor layer V1 generally has a size (length in a given direction) larger than the wavelength of light. For example, the characteristic scale of the vapor layer of a water droplet in the atmosphere can be seen from the diffusion equation as being the diameter of the water droplet and the degree of identification. That is, for a water droplet on the order of millimeters, the measurement unit M can be placed at a distance of more than 1000 times the wavelength of light from the water droplet (liquid droplet D1). This makes it possible to identify physical properties at an interval where the effect of capillary force, which was a problem in conventional liquid property identification, can be sufficiently ignored.

[0033] Furthermore, since the energy density of the vapor layer V1 is significantly lower than that of the droplet D1 itself, its light absorption is also significantly smaller than that of the droplet D1. Therefore, physical property identification can be achieved while reducing the degradation of the optical resonator 14's characteristics. Moreover, by not degrading the optical properties of the optical resonator 14, extreme measurements capable of detecting even slight changes in physical properties can be realized.

[0034] (Measurement Method 2) Since there is a correlation between the vapor density of the vapor layer V1 and the optical resonance frequency, the time change in vapor density at a certain position in the vapor layer V1 can also be measured by monitoring the time change in the optical resonance frequency. In such a case, the processing unit 19 fixes the position of the measurement unit M (especially the optical resonator 14) and performs analysis of the emission of the laser light from the light source 16 and the electrical signal from the photodetector 17 that represents the light detected by the photodetector 17 at different timings. The time change in vapor density may indicate a change in the physical properties of the droplet D1 (for example, a change in temperature, a change in composition, etc.). Therefore, the processing unit 19 may identify the change in the physical properties of the droplet D1 based on the time change in vapor density by performing a predetermined process and output the identification result. If there is a one-to-one correspondence between the change in the physical properties of the droplet D1 and the time change in vapor density, the processing unit 19 may directly derive the change in the physical properties of the droplet D1 as a type of time change in vapor density based on the optical resonance frequency.

[0035] In this example, by utilizing the correlation between the optical resonance frequency and the time evolution of vapor density, it is possible to measure the time evolution of the vapor density of the vapor layer V1 produced by evaporation from a liquid (here, a liquid droplet D1, but not limited to a liquid droplet) using the measurement unit M (especially the optical resonator 14). The effect on identifying physical properties is the same as the effect of measurement method 1 described above.

[0036] (Modified Measurement Device and Measurement Method 3) As shown in Figure 6, at least the tapered fiber 12, optical resonator 14, and inspection stand S of the measurement device 10 may be introduced into the constant temperature and high humidity chamber 30. Figure 7 shows the relationship between the optical resonance frequency and the distance of the measurement unit M from the inspection stand S when the humidity in the constant temperature and high humidity chamber 30 is changed to 10 to 90% and the above measurement method 1 is performed (the explanation of the vertical and horizontal axes is the same as in Figure 4). As shown in Figure 7, the degree of change of the optical resonance frequency with respect to the change in distance differs depending on the humidity. In particular, the degree of change is greater at lower humidity. In this way, the measurement sensitivity of the change in vapor density can be adjusted by controlling the atmosphere (especially) of the space in which the vapor layer V1 exists (the space around the vapor layer V1). Note that the atmosphere may be controlled by a device other than the constant temperature and high humidity chamber (for example, an air conditioning system).

[0037] Assuming droplet D1 is a perfect sphere, its initial diameter is R, the relative humidity of the surrounding space is H, and the saturation density is n. ｓａｔ Therefore, the vapor density n(r) at a distance r from the center of the droplet is expressed by the following formula (1). As explained above, by assuming that the refractive index around the optical resonator 14 is proportional to the vapor density, the curve shown in Figure 7 is obtained.

[0038] (Modified Measurement Device and Measurement Method 4) As shown in Figure 8, instead of the inspection table S, an inspection table S1 may be provided which includes a piezoelectric element or the like and vibrates the droplet D1. The processing unit 19 drives the inspection table S1 to vibrate the droplet D1. The vibration generates a surface tension wave in the droplet D1.

[0039] Figure 9 shows the results (vibration spectra) of measuring the time evolution of vapor density for each frequency by measurement method 2 after sweeping the frequency of the AC voltage applied to the piezoelectric element (frequency of the surface tension wave of droplet D1). Droplet D1 is pure water. The amplitude on the vertical axis of Figure 9 is the normalized value of the difference between the maximum and minimum values ​​of the time evolution of the optical resonance frequency (which can also be called the time evolution of vapor density at a certain position) at the frequency of the surface tension wave. As can be seen from Figure 9, three spectra are observed, which are the first, second, and third natural vibration frequencies from low frequency to high frequency. Furthermore, Figure 10 shows the change in the first natural vibration frequency (experimental value) when the diameter of droplet D1 is changed. As shown in Figure 10, the first natural vibration frequency increases as the diameter decreases, and the experimental values ​​are distributed around the theoretical value of the natural vibration frequency for a perfectly spherical droplet (dotted line in the figure), which indicates that the natural vibration frequency can be detected from the time evolution of the optical resonance frequency. Furthermore, the natural vibration frequency can be described as a type of change in the vapor density of the vapor bed V1, or more specifically, a change over time.

[0040] Based on the above, the processing unit 19 can identify (measure) the natural vibration frequency of droplet D1 as a time change in vapor density, using a predetermined table or function derived in advance through experiments or other means, based on the measured change in optical resonance frequency. Alternatively, the processing unit 19 may identify the physical properties of droplet D1 based on its natural vibration frequency.

[0041] (Modification of the measuring device and measurement method 5) As shown in Figure 11, the measurement target can be changed from the natural vibration frequency of the droplet D1 to the natural vibration frequency of the cultured cell sample SP1. The cultured cell sample SP1 is a sample that is preferably cultured at a gas-liquid interface, for example, a dispersed culture system of epithelial cells or a slice tissue culture system of various organs, and contains liquid. A vapor layer V2 is generated by the liquid in this cultured cell sample SP1, and the measuring unit M is positioned within this vapor layer V2.

[0042] The natural vibration frequency of the cultured cell sample SP1 can be measured in the same manner as in measurement method 4 described above. The processing unit 19 may identify the physical properties of the cultured cell sample SP1 based on the natural vibration frequency.

[0043] When using adherent cells in the cultured cell sample SP1, it is desirable to use a hydrogel or a porous membrane as the medium SP2 for supplying nutrients in water or the culture solution. Furthermore, by changing the number of cells in the cell population, it is possible to capture the change in the natural frequency depending on the scale or binding state of the population. Also, due to the characteristic of this method that measurement can be performed non-contact with respect to the object, continuous measurement is possible without damaging the cultured cells, and it can also be applied to visualize the growth process such as cell growth and formation of cell-cell binding.

[0044] Instead of the above-mentioned cultured cell sample SP1 and medium SP2, a soft material may be used as the measurement target. Examples of soft materials include hydrogels containing water as a solvent or organogels containing an organic solvent as a solvent, which are arranged in a three-dimensional polymer network. By holding these soft materials in the air, a vapor layer is three-dimensionally formed due to the evaporation of the solvent, and by bringing an optical resonator close to the sample at an appropriate distance, the natural vibration frequency corresponding to the physical properties of the soft material can be measured. For example, by changing the composition of the polymer network forming the soft material, it is possible to detect the change in the natural frequency depending on the elastic modulus or the solvent content rate. In addition, by using a stimulus-responsive material in which the compatibility between the polymer three-dimensional network and the solvent changes in response to a stimulus, the time change of the physical property value in response to the stimulus can be measured non-contact.

[0045] (Modified example of the measuring device) As shown in FIG. 12, the measuring device 10 may be held by the tip of the nozzle of a dispenser 40 that holds the droplet D1 at the nozzle tip. As shown in FIG. 12, an object containing a liquid such as the droplet D1 that generates the vapor layer V3 may be above or below the measuring unit M.

[0046] Generate an appropriate amount of droplets from the nozzle. By configuring the dispenser and the optical resonator as shown in FIG. 8c, the time change of the diffusion field using the optical resonator is measured.

[0047] (Others) The tapered fiber 12 may be changed to other optical waveguides. Also, the optical resonator 14 may be changed to other types of micro optical resonators. The processing unit 19 may identify the mechanical properties or viscoelasticity of an object from the natural vibration frequency and the shape of the object (assumed to be known) such as the droplet D1. Further, the above vibration may be applied to the object to amplify the change in the vapor density of the vapor layer V1. The processing unit 19 detects the time change of the optical resonance frequency due to the surface tension wave generated at the gas-liquid interface for a liquid contained in a container whose shape is known and part of which is in contact with the atmosphere, or for a droplet whose shape is known, and may enable the identification of the surface tension from the natural vibration frequency of the surface tension wave and the shape of the object. The processing unit 19 may identify the volume change accompanying the evaporation of the liquid of the object from the measured time change of the vapor density, and estimate the evaporation rate from the identification result. Furthermore, the processing unit 19 may identify unknown thermal properties by solving the diffusion equation using the evaporation rate and the surrounding environmental parameters.

[0048] (Scope of the Invention) The present invention is not limited to the above-described embodiments and modifications. For example, the present invention includes various modifications to the above-described embodiments and modifications that can be understood by those skilled in the art within the scope of the technical idea of the present invention. Each configuration described in the above embodiments and modifications can be appropriately combined within a non-contradictory range. Also, any one of the above configurations can be deleted.

[0049] (Supplementary Note) Configurations taking the above embodiments and modifications as examples are illustrated below. For each supplementary note, only any partial configuration of the above embodiments and modifications can be applied. Also, some of the supplementary notes may be combined with each other.

[0050] (Note 1) A measurement method comprising: a first step of placing a measuring unit having at least a portion of an optical waveguide and a minute optical resonator through which at least a portion of the light that is optically coupled with the at least portion and propagates through the optical waveguide passes, in a vapor layer formed by a liquid contained in an object, in which light is incident on the optical waveguide and the optical resonance frequency of the light emitted from the optical waveguide is detected multiple times; and a second step of identifying a change in the vapor density of the vapor layer based on the optical resonance frequencies obtained by each of the multiple processes performed in the first step.

[0051] (Note 2) The measurement method according to Note 1, wherein in the first step, the relative position of the measuring unit with respect to the object is changed in each of the multiple processes, and in the second step, the distribution of the vapor density of the vapor layer is identified as the change in vapor density.

[0052] (Note 3) The measurement method according to Note 2, further comprising a third step of identifying the physical properties of the object based on the distribution of the vapor density of the vapor layer.

[0053] (Note 4) The measurement method described in Note 1, wherein in the first step, the position of the measuring unit is fixed, and the multiple processes are performed sequentially at different timings, and in the second step, the change in steam density is identified as the change in steam density over time at the fixed position of the steam layer.

[0054] (Appendix 5) The measurement method according to Appendix 4, further comprising a fourth step of identifying the time change of the physical properties of the object based on the time change of the vapor layer.

[0055] (Appendix 6) The measurement method according to any one of Appendix 1 to 5, further comprising a fifth step of vibrating the object, wherein the second step specifies the natural vibration frequency of the object as a change in vapor density.

[0056] (Appendix 7) The measurement method according to any one of Appendix 1 to 6, further comprising a sixth step of controlling the atmosphere surrounding the steam layer.

[0057] (Note 8) A measuring device comprising: a measuring unit having at least a portion of an optical waveguide and a minute optical resonator through which at least a portion of the light that is optically coupled with the at least portion and propagates through the optical waveguide passes; a driving mechanism for moving the measuring unit and an object relative to each other; and a processing unit that controls the driving mechanism to position the measuring unit in a vapor layer formed by a liquid contained in the object, and performs a process multiple times in which the light is incident on the optical waveguide and the optical resonance frequency of the light emitted from the optical waveguide is detected, wherein the processing unit identifies a change in the vapor density of the vapor layer based on the optical resonance frequency obtained by each of the multiple processes.

[0058] 10... Measuring device, 11... Support member, 11A... Main body, 11B... Arm, 11C... Arm, 12... Tapered fiber, 12A... Small diameter section, 13... Support member, 14... Optical resonator, 15... Fixing material, 15A-15C... Fixing material, 16... Light source, 17... Photodetector, 18... Drive mechanism, 18... Movement mechanism, 19... Processing unit, 30... Constant temperature and high humidity chamber, 40... Dispenser, D1... Droplet, M... Measuring unit, S... Inspection table, S1... Inspection table, SP1... Cultured cell sample, SP2... Culture medium, V1-V3... Vapor layer.

Claims

1. A measurement method comprising:

1. Placing a measuring unit having at least a portion of an optical waveguide and a minute optical resonator through which at least a portion of the light that is optically coupled to the at least portion and propagates through the optical waveguide passes, within a vapor layer formed by a liquid contained in an object, in which light is incident on the optical waveguide and the optical resonance frequency of the light emitted from the optical waveguide is detected multiple times; and 2. Identifying a change in the vapor density of the vapor layer based on the optical resonance frequencies obtained from each of the multiple processes performed in the first step.

2. The measurement method according to claim 1, wherein in the first step, the relative position of the measuring unit with respect to the object is changed in each of the multiple processes, and in the second step, the distribution of the vapor density of the vapor layer is identified as the change in vapor density.

3. The measurement method according to claim 2, further comprising a third step of identifying the physical properties of the object based on the distribution of the vapor density of the vapor layer.

4. The measurement method according to claim 1, wherein in the first step, the position of the measuring unit is fixed, and the multiple processes are performed sequentially at different timings, and in the second step, the change in steam density is identified as the change in steam density over time at the fixed position of the steam layer.

5. The measurement method according to claim 4, further comprising a fourth step of identifying the time change of the physical properties of the object based on the time change of the vapor layer.

6. The measurement method according to claim 1, further comprising a fifth step of vibrating the object, wherein the second step specifies the natural vibration frequency of the object as a change in vapor density.

7. The measurement method according to claim 1, further comprising a sixth step of controlling the atmosphere surrounding the vapor layer.

8. A measuring device comprising: a measuring unit having at least a portion of an optical waveguide and a minute optical resonator through which at least a portion of the light that is optically coupled with the at least portion and propagates through the optical waveguide passes; a driving mechanism for moving the measuring unit and an object relative to each other; and a processing unit that controls the driving mechanism to position the measuring unit in a vapor layer formed by a liquid contained in the object, and performs a process multiple times in which the light is incident on the optical waveguide and the optical resonance frequency of the light emitted from the optical waveguide is detected, wherein the processing unit identifies a change in the vapor density of the vapor layer based on the optical resonance frequency obtained by each of the multiple processes.

Images