JP2008209160A - Hollow fiber bundle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive hollow fiber bundle that can be applied movably in a large range and can improve the light quantity received. <P>SOLUTION: This hollow fiber bundle comprises a hollow fiber 2 for irradiation for propagating broad band light, including infrared light or dispersed infrared light and irradiating a measuring object 14 with them, and a hollow fiber 3 for detection for receiving and propagating transmitted light, reflected light, or scattered light from the measuring object 14. The hollow fiber 2 for irradiation and the hollow fiber 3 for detection are bundled on one end side and are separated from each other on the other end side to form a hollow fiber bundle 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hollow fiber bundle, and more particularly to a hollow fiber bundle suitable for a spectroscopic analysis apparatus that propagates light in an infrared wavelength band and performs spectroscopic analysis of chemical substances, living cells, gases, and the like.

Conventionally, infrared absorption spectra are measured and analyzed for analysis of chemical substances such as proteins, fatty acids, alcohols, sugars, and pigments, understanding the state of the molecules that make up living cells, monitoring chemical reactions, and analyzing gas concentrations. Infrared spectroscopy is widely used.
In an infrared spectroscopic analyzer that realizes this, a specific sample is irradiated with light dispersed by a Fourier transform infrared (FTIR) spectrometer or a monochromator, and the light transmitted through the sample, or the light reflected or scattered from the sample Is received by a detector such as MCT (Mercury Cadmium Tellurium), the infrared absorption spectrum is measured, and quantitative analysis is performed from the absorption characteristics. Alternatively, a configuration is also possible in which the sample is irradiated with broadband light, and the absorption spectrum is measured by performing spectroscopy on the detector side.

As an optical component for infrared spectroscopic analysis, multiple light sources are used to guide the light from the light source and irradiate the sample, and to receive the light transmitted through the sample or the light reflected or scattered from the sample and guide it to the detector. There is known a Y-shaped optical fiber bundle in which an optical fiber of a type is bundled at one end and separated into two at the other end (see Patent Document 1).
In the conventional infrared spectroscopic analyzer using this optical fiber bundle, as shown in FIG. 4A, there are seven irradiation optical fibers 43 on the light source 41 and spectroscope 42 side, and detection on the detector 47 side. Twelve optical fibers 46, a total of 19 chalcogenide optical fibers, are used. These optical fibers 43 and 46 are bundled together on the sample 45 side, and are reflected twice at the tip of the bundled portion. 44 is used as an optical fiber probe to which 44 is attached. The optical fiber bundling portion on the sample 45 side is a state in which the irradiation optical fiber 43 and the detection optical fiber 46 are mixed, as shown in FIG. It is fixed and its end surface is polished flat.
The split infrared light is incident on the ZnSe prism 44 by the irradiation optical fiber 43, and the prism 44 is pressed against the sample 45 to transmit the light propagating through the sample 45 while being absorbed as evanescent light to the detection optical fiber 46. Then, an infrared absorption spectrum is measured by the detector 47. Since an optical fiber is used, the movable range of the measurement part is widened, and it can be used for various measurement sites.

Conventionally, as shown in FIG. 5, a spectroscopic analyzer using a hollow fiber 53 as a probe for irradiating a sample 54 has been proposed (see Patent Document 2). FIG. 5A is a measurement example for measuring the transmitted light. The light from the light source 51 is dispersed by the spectroscope 52, and the sampled light is irradiated to the sample 54 by the hollow fiber 53 as a probe. The transmitted transmitted light is spectrally analyzed by the detector 55.
FIG. 5B is a measurement example for measuring reflected light and scattered light. Light reflected or scattered from the sample 54 and propagated through the hollow fiber 53 in the reverse direction is detected by a semi-transparent mirror 56 and a reflecting mirror 57. To conduct spectroscopic analysis.
The tip opening of the hollow fiber 53 is brought into contact with or close to the sample 54, and the sample 54 is irradiated with the dispersed infrared light emitted from the opening of the hollow fiber 53. Since the probe is formed by the hollow fiber 53, there is no generation of auto-fluorescence of the fiber during the optical waveguide unlike the solid-state infrared transmission optical fiber, and the analysis accuracy can be improved.
US Patent No. 5170056 JP 2004-294150 A

In the Y-shaped optical fiber bundle in which a plurality of solid optical fibers 43 and 46 shown in FIG. 4 are bundled at one end and separated at the other end, the amount of received light is improved by bundling a large number of optical fibers. However, in applications where blood glucose levels are measured non-invasively, it is necessary to further improve analysis accuracy.
Since a solid optical fiber is used, the plurality of optical fibers 43 and 46 bound on the sample 45 side are bonded and fixed, and the end surfaces are uniformly polished. Therefore, although the distance between the probe tip and the sample can be arbitrarily adjusted, the amount of detection light received with respect to the amount of light irradiated on the sample cannot be adjusted independently. Although the prism 44 is attached to the tip to devise a large amount of received light, the irradiation optical fiber 43 and the detection optical fiber 46 are not arranged so as to maximize the amount of received light. Also, it cannot be adjusted to maximize the amount of received light.
In addition, chalcogenide glass that enables infrared light transmission is used for the optical fiber, but this is a toxic material and not a material suitable for bioanalysis for medical purposes. ZnSe of the prism 44 that must be attached to the tip is also a toxic material, and calcium fluoride, which is also a general infrared optical material, is deliquescent and is not suitable for insertion into, contact with, or access to a wet sample. . In addition, a solid optical fiber may generate autofluorescence, which is an obstacle to high-precision analysis.

  In the spectroscopic analysis apparatus shown in FIG. 5, in the measurement of the transmitted light in FIG. 5A, the detected light amount greatly depends on the thickness of the sample and the absorption characteristics of the container (stage), and is limited by the detection target substance. Further, in the measurement of reflected light and scattered light in FIG. 5B, the weak reflected light or scattered light from the sample 54 is propagated in the same hollow fiber 53 in the opposite direction to the incident light, and half The incident light is separated by the transmission mirror 56. As a result, the amount of light actually received by the detector is quite weak. Further, since the measurement system is fixed in both the measurement example based on the transmitted light in FIG. 5A and the measurement example based on the reflected light and the scattered light in FIG. 5B, there is a limitation in measuring a wide range of parts. . Further, the spectroscopic analysis of FIG. 5 aims at analyzing a sample placed in a liquid. In such an environment, foreign matter enters the hollow fiber 53 whose both ends are open from the outside. Even if it is possible to prevent damage to the hollow fiber itself due to foreign substance intrusion by using a hollow fiber having high water repellency, the detection sensitivity is greatly deteriorated due to contamination of the inner wall of the hollow fiber.

  An object of the present invention is to provide an inexpensive hollow fiber bundle that can solve the above-described problems and can be applied in a wide range and can improve the amount of received light.

In order to solve the above problems, the present invention is configured as follows.
According to a first aspect of the present invention, there is provided an irradiation hollow fiber that propagates broadband light including infrared light or dispersed infrared light to irradiate the object to be measured, and transmitted light, reflected light of the object to be measured, A hollow fiber bundle in which a hollow fiber for detection that receives and propagates scattered light is bundled.

  According to a second aspect of the present invention, there is provided an irradiation hollow fiber for propagating a broadband light including infrared light or a dispersed infrared light to irradiate the object to be measured, and transmitted light, reflected light or A hollow hollow fiber for detecting and propagating scattered light, the hollow hollow fiber for irradiation and the hollow hollow fiber for detection being bundled at one end side and separated at the other end side It is a fiber bundle.

  According to a third aspect of the present invention, in the hollow fiber bundle of the first aspect or the second aspect, the end face of the irradiation hollow fiber and the end face of the detection hollow fiber on the measured object side are shifted in position. It is characterized by being arranged.

  According to a fourth aspect of the present invention, in the hollow fiber bundle of the first aspect or the second aspect, the irradiation hollow fiber and the detection hollow fiber on the measured object side are relatively positioned at end surfaces. It is characterized by being bundled so that movement adjustment is possible.

  According to a fifth aspect of the present invention, in the hollow fiber bundle according to any one of the first to fourth aspects, the irradiation hollow fiber is disposed at a central portion, and the detection hollow fiber is around the irradiation hollow fiber. It is arrange | positioned at the part and is bundled.

  According to a sixth aspect of the present invention, in the hollow fiber bundle according to any one of the first to fourth aspects, the detection hollow fiber is disposed at a central portion, and the irradiation hollow fiber is around the detection hollow fiber. It is arrange | positioned at the part and is bundled.

  According to a seventh aspect of the present invention, in the hollow fiber bundle of any one of the first to fourth aspects, the irradiation hollow fiber is in one approximately half of the binding cross section, and the detection hollow fiber is in the other half. It arrange | positions at the substantially half piece, It is characterized by the above-mentioned.

  According to an eighth aspect of the present invention, in the hollow fiber bundle according to any one of the first to seventh aspects, the infrared rays propagated by the distal end surfaces on the measured object side of the irradiation hollow fiber and the detection hollow fiber. It is sealed with a sealing member that is transparent to light.

  According to a ninth aspect of the present invention, in the hollow fiber bundle according to any one of the first to seventh aspects, the inside of the irradiation hollow fiber and the detection hollow fiber is maintained at a positive pressure. To do.

  According to a tenth aspect of the present invention, in the hollow fiber bundle according to any one of the first to ninth aspects, the irradiation hollow fiber and the detection hollow fiber are arranged on an inner peripheral surface of a tubular member constituting the waveguide. A hollow fiber in which a dielectric thin film transparent to the transmitted infrared light is formed.

According to the present invention, since a plurality of hollow fibers are bundled and bundled, the amount of received light can be increased, and it can be applied to a wide range of measurement locations. In addition, compared to conventional solid-state optical fibers, hollow fibers can generally be easily manufactured with large core diameters, so that sufficient light reception can be ensured even with a smaller number of bundles, and end face polishing is performed. Therefore, an effective structure can be realized at a low price.
Further, the end surfaces of the irradiation hollow fiber and the detection hollow fiber on the side of the object to be measured are arranged so that the positions of the end surfaces are shifted, or the end surfaces are bound so that the position of the end surfaces can be relatively moved and adjusted. Therefore, the light receiving sensitivity of the detection light from the object to be measured can be improved.

  Embodiments of a hollow fiber bundle according to the present invention will be described below with reference to the drawings. Fig.1 (a) is a schematic block diagram of the spectrometer which uses the hollow fiber bundle of one Embodiment of this invention, FIG.1 (b) is AA expanded sectional drawing of Fig.1 (a). .

The hollow fiber bundle 1 of this embodiment has one irradiation hollow fiber 2 and six detection hollow fibers 3. One end side (sample 14 side) of the irradiation hollow fiber 2 and the detection hollow fiber 3 is inserted into a cylindrical ferrule 7 and bound together. The ferrule 7 is provided as an optical fiber probe close to or in contact with the sample 14. Further, the irradiation hollow fiber 2 and the detection hollow fiber 3 bundled together by the ferrule 7 are divided into the irradiation hollow fiber 2 and the detection hollow fiber 3 from the connector 6 part. The irradiation hollow fiber 2 is housed in a protective tube 4, the other end of the irradiation hollow fiber 2 is optically connected to the spectrometer 12, and the detection hollow fiber 3 is housed in a protective tube 5 for detection. The other end of the hollow fiber 3 for use is optically connected to the detector 15.

A dielectric that has a hollow core and is capable of transmitting light in the infrared wavelength region with low loss, and has a dielectric thin film that is transparent to the transmitted infrared light on the inner wall of the tubular member that constitutes the waveguide. A body-internal hollow fiber is known (see, for example, Japanese Patent No. 3566232). As the dielectric thin film, a transparent dielectric material such as a cyclic olefin polymer or a silver halide material is used. The tubular member is made of a metal pipe such as phosphor bronze or stainless steel, or a non-metal pipe such as quartz glass or fluororesin, and a metal thin film such as silver, gold, molybdenum or nickel is formed on the inner wall of the non-metal pipe or metal pipe. Provided.
In the present embodiment, a quartz glass capillary having a polyimide protective film formed on the outer peripheral portion is used as the irradiation hollow fiber 2 and the detection hollow fiber 3, and a silver thin film and a cyclic olefin polymer thin film are formed on the inner peripheral surface thereof. A dielectric-filled metal hollow fiber was used. This dielectric-incorporated metal hollow fiber has an inner diameter of 700 μm and an outer diameter of 850 μm.

  Infrared light emitted from the light source 11 and dispersed by the spectroscope 12 is guided to the irradiation hollow fiber 2 and irradiated onto the sample 14 on the stage 13. Light transmitted, reflected or scattered by the sample 14 is received by the detection hollow fiber 3. The light propagated through the detection hollow fiber 3 is received by the detector 15 and the infrared absorption spectrum of the sample 14 is measured.

  As shown in the cross section of the optical fiber in FIG. 1B, the irradiation hollow fiber 2 is formed as a bundled portion (ferrule 7 portion) in which the irradiation hollow fiber 2 and the detection hollow fiber 3 are united. At the center, the detection hollow fiber 3 is arranged at the periphery. In this embodiment, as shown in FIG. 1B, one irradiation hollow fiber 2 and six detection hollow fibers 3 on the outer periphery thereof are used. The three detection hollow fibers may use a larger number of hollow fibers so as to surround these irradiation hollow fibers. In the present embodiment, as described above, both the irradiation hollow fiber 2 and the detection hollow fiber 3 have an inner diameter of 700 μm and an outer diameter of 850 μm. However, hollow fibers having different diameters may be used.

  In this embodiment, a dielectric-incorporated metal hollow fiber with a cyclic olefin polymer is used. However, the transmittance of a hollow silver fiber without a dielectric is at most several percent. Therefore, when a metal hollow fiber not including a dielectric is used as the irradiation hollow fiber 2 and the detection hollow fiber 3, the amount of light irradiated on the sample 14 is very weak and propagates through the detection hollow fiber 3. The amount of light received by the detector 15 becomes a noise level, and it is difficult to perform accurate spectroscopic analysis. In contrast, by using a metal hollow fiber with a transparent dielectric material in the infrared region, the transmission line has a transmittance of about 70% in a transmission line of about 1 m in length, and sufficient sensitivity necessary for infrared spectroscopic analysis. Is obtained.

The arrangement of the irradiation hollow fiber 2 and the detection hollow fiber 3 in the ferrule 7 is not limited to the arrangement of FIG. 1B, but as shown in FIG. The irradiation hollow fiber 2 may be arranged around the detection hollow fiber 3. In this arrangement, if the hollow fibers connected to the light source 11 side and the detector 15 side in FIG. 1 (a) are connected in reverse, the analysis can be easily performed using the hollow fiber bundle 1 having the same structure as FIG. The device can be configured.

  Further, as shown in FIG. 2 (b), the irradiation hollow fiber 2 is arranged in a substantially half half of the cross section in the ferrule 8 and the detection hollow fiber 3 is arranged in another substantially half half in the elliptical ferrule 8. You may let them. In FIG. 2B, three irradiation hollow fibers 2 and three detection hollow fibers 3 are used. However, for example, a structure in which each one is used and arranged in parallel and bundled may be used. Good.

  The number and arrangement of the hollow fibers are selected depending on the size and shape of the sample 14 to be measured, the absorption rate by the material, the amount of reflection / scattering, and the like. For example, when the sample is very small, the configuration shown in FIG. 1B is advantageous, and when the sample has a certain size, the configuration shown in FIG. . When the sample is elliptical, the configuration shown in FIG. 2B can increase the amount of received light.

  In the embodiment of FIG. 1, the irradiation hollow fiber and the detection hollow fiber have a Y-shaped structure in which one end is bound and the other end is separated into two. A bundle of hollow fiber bundles may be used. In this case, the irradiation light and the detection light propagate in opposite directions in the hollow fiber, and the same hollow fiber serves as both the irradiation hollow fiber and the detection hollow fiber. In the case of such a configuration, the irradiation light and the detection light may be separated by using a semi-transparent mirror or the like as shown in FIG. Even if it is not a hollow fiber bundle structure in which one end is separated in this way, since it is a structure in which a plurality of hollow fibers are bundled, the light receiving area is wide and a large amount of detection light can be received. It can analyze with higher sensitivity than the conventional technology.

  When measuring the transmitted light that has passed through the sample, for example, the detection hollow fiber 3 facing the sample 14 in FIG. 1 is routed behind the stage 13 on which the sample 14 is placed and arranged to receive light. Also good. In this case, the hollow fiber bundle may be bundled at an intermediate portion thereof or at an end portion side on the light source and detector side.

FIG. 3 shows another embodiment of the hollow fiber bundle of the present invention.
As shown in FIG. 3 (a), the hollow fiber bundle of this embodiment includes an end surface of the irradiation hollow fiber 2 and an end surface of the detection hollow fiber 3 in the portion on the sample 14 side (ferrule 31) that is bound. The positions of are not on the same plane, and the positions of the end faces are shifted in the fiber longitudinal direction. Specifically, the end face of the irradiation hollow fiber 2 is disposed deeper in the ferrule 31 than the end face of the detection hollow fiber 3. Further, as shown in FIG. 3B, which is a BB cross-sectional view of FIG. 3A, one irradiation hollow fiber 2 is provided at the center of the ferrule 31, and the outer peripheral portion of the irradiation hollow fiber 2. The six detection hollow fibers 3 are provided in each. In addition, a window transparent to infrared light transmitted by the hollow fibers 2 and 3 is used as a sealing member that seals the inside of the hollow fibers 2 and 3 so that foreign matter does not enter the hollow ends of the ferrule 31. 32 is fitted.

  In general, the hollow fiber has a smaller divergence angle of the outgoing light as compared to a solid optical fiber having a solid core. Therefore, if the end face of the irradiation hollow fiber 2 and the end face of the detection hollow fiber 3 are on the same plane, the detection light from the sample 14 is detected by the detection hollow fiber 3 with respect to the light irradiated from the irradiation hollow fiber 2. However, the ratio of returning to the irradiation hollow fiber 2 that has emitted the irradiation light increases. Therefore, as shown in FIG. 3, the detection hollow fiber 3 can receive the detection light more efficiently by adopting a structure in which the end face position of the irradiation hollow fiber 2 and the end face position of the detection hollow fiber 3 are not in the same plane. And a highly sensitive infrared spectroscopic analyzer can be constructed. Unlike a solid optical fiber, a hollow fiber does not require polishing of its end face, and a light receiving surface can be secured only by cutting, so that it is easy to realize such a structure.

Since the positions of the end faces of the hollow fibers 2 and 3 are optimum depending on the sample shape or the like, the irradiation hollow fiber 2 is maintained while the irradiation hollow fiber 2 and the detection hollow fiber 3 are kept in a bundled state. It is preferable to adopt a structure in which the position of the end face of the detection hollow fiber 3 can be moved relatively.
Specifically, in FIG. 3A, the distance a between the tip of the ferrule 31 serving as the probe of the hollow fiber bundle and the sample 14, the end surface position of the irradiation hollow fiber 2, and the end surface position of the detection hollow fiber 3 The distance b can be independently adjusted so as to maximize the amount of light received by the detector.
Note that the end face positions of the plurality of irradiation hollow fibers may be shifted, or the end face positions of the plurality of detection hollow fibers may be shifted. Also, for example, a ferrule into which the irradiation hollow fiber and the detection hollow fiber are inserted can be moved in the axial direction with a double tube structure that divides the irradiation hollow fiber and the detection hollow fiber into each other. It may be configured. Furthermore, the end face of the hollow fiber may be moved using a mechanism such as a feed screw.

  In general, in the case of a hollow fiber, the divergence angle of the emitted light is smaller than that of the solid optical fiber, and the end face position of the irradiation hollow fiber 2 is arranged behind the end face position of the detection hollow fiber 3 as shown in FIG. It is possible to increase the amount of received light. However, when the shape of the sample 14 is concave, the sensitivity may increase when the end face position of the irradiation hollow fiber 2 is protruded from the end face position of the detection hollow fiber 3. It is effective to adjust the position of the end face of each of the hollow fibers 2 and 3 while monitoring the amount. In this way, by adopting a configuration in which the position of the end face can be moved and adjusted, the spectroscopic analyzer using the conventional solid optical fiber bundle shown in FIG. Highly sensitive spectroscopic analysis has become possible.

  That is, as the hollow fibers 2 and 3, the same olefin polymer-embedded silver hollow fiber having an inner diameter of 700 μm and an outer diameter of 850 μm, which is the same as that of the embodiment of FIG. 1, is used, and the irradiation hollow fiber 2 shown in FIG. By adjusting the position of the end face of the six detection hollow fibers 3, 19 solid chalcogenide lights in total, including the seven irradiation optical fibers and the 12 detection optical fibers shown in FIG. Compared with an optical fiber bundle using a fiber, about twice the amount of light received by the detector could be obtained.

  Further, the hollow fiber bundle is adapted to infrared light propagating through the hollow fibers 2 and 3 so that a specific foreign substance does not enter the hollow fibers 2 and 3 even if one end is inserted or approached to the sample 14. On the other hand, a transparent window 32 was attached to the tip of the ferrule 31. As the window material, an inorganic material such as silicon, germanium, zinc selenide, selenium sulfide, or calcium fluoride that is transparent in the infrared region is used, but a resin having an infrared absorption that does not match the intrinsic absorption peak of the sample 14 A functional material can also be used. In this case, the cap shape may be molded and attached so as to cover not only the flat window 32 but also the entire tip of the hollow fiber bundle. Alternatively, rather than using a sealing member such as a window or a cap, by supplying a gas to the inside of the hollow fibers 2 and 3 to make a positive pressure, foreign matter intrusions into the hollow fibers 2 and 3 from the outside. It is also possible to prevent.

  In the above embodiment, the infrared light split by the spectroscope 12 is used as the light that propagates through the irradiation hollow fiber 2 and irradiates the sample 14. However, the sample 14 is irradiated with broadband light including infrared light. In addition, a configuration in which the infrared absorption spectrum characteristic is measured by performing spectroscopy on the detector 15 side is also possible.

(A) is a schematic block diagram of the spectrometer which used the hollow fiber bundle of one Embodiment of this invention, (b) is AA expanded sectional drawing of (a). It is a cross-sectional view which shows the cross-sectional structure in the binding part of the hollow fiber bundle of other embodiment of this invention. It is a longitudinal cross-sectional view in the sample side of the hollow fiber bundle of other embodiment of this invention, (b) is BB sectional drawing of (a). (A) is a schematic block diagram of the spectrometer which used the conventional solid optical fiber bundle, (b) is CC expanded sectional drawing of (a). It is a schematic block diagram of the spectrometer which used the conventional hollow fiber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hollow fiber bundle 2 Irradiation hollow fiber 3 Detection hollow fiber 4, 5 Protective tube 6 Connector 7 Ferrule 8 Ferrule 11 Light source 12 Spectrometer 14 Sample (measurement object)
15 Detector 31 Ferrule 32 Window (sealing member)

Claims (10)

  An irradiation hollow fiber that propagates broadband light including infrared light or spectral infrared light to irradiate the object to be measured, and detection that propagates by receiving transmitted light, reflected light, or scattered light of the object to be measured. A hollow fiber bundle characterized in that the hollow fiber is bundled.   An irradiation hollow fiber that propagates broadband light including infrared light or spectral infrared light to irradiate the object to be measured, and detection that propagates by receiving transmitted light, reflected light, or scattered light of the object to be measured. A hollow fiber bundle, wherein the irradiation hollow fiber and the detection hollow fiber are bundled at one end and separated at the other end.   3. The hollow fiber bundle according to claim 1, wherein an end face of the irradiation hollow fiber and an end face of the detection hollow fiber on the object to be measured side are arranged to be shifted in position.   The hollow fiber bundle according to claim 1 or 2, wherein the irradiation hollow fiber and the detection hollow fiber on the object to be measured are bound so that the position of the end face can be relatively adjusted.   The said irradiation hollow fiber is arrange | positioned in the center part, and the said detection hollow fiber is arrange | positioned and bound in the peripheral part of the said irradiation hollow fiber, The one in any one of Claims 1-4 characterized by the above-mentioned. Hollow fiber bundle.   The said detection hollow fiber is arrange | positioned in the center part, The said hollow fiber for irradiation is arrange | positioned in the peripheral part of the said detection hollow fiber, and is bundled. Hollow fiber bundle.   The hollow according to any one of claims 1 to 4, wherein the irradiation hollow fiber is disposed in one approximately half of the binding cross section, and the detection hollow fiber is disposed in the other approximately half. Fiber bundle.   8. The irradiation hollow fiber and the detection hollow fiber are sealed by a sealing member that is transparent to infrared light propagating on the measured object side end surfaces. The hollow fiber bundle according to any one of the above.   The hollow fiber bundle according to any one of claims 1 to 7, wherein the inside of the hollow fiber for irradiation and the hollow fiber for detection are held at a positive pressure.   The irradiation hollow fiber and the detection hollow fiber are hollow fibers in which a dielectric thin film transparent to infrared light to be transmitted is formed on an inner peripheral surface of a tubular member constituting a waveguide. The hollow fiber bundle according to any one of claims 1 to 9.

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