JPH0862133A - Microscopic infrared spectrophotometer - Google Patents

Abstract

PURPOSE: To realize measurement of infrared absorption spectrum in a micro region using a nonlinear phenomenon. CONSTITUTION: A variable wavelength infrared laser beam from a light source 1 is projected to a sample and the transmitted infrared beam 4 impinges on a crystal 5 of nonlinear material. A second or third harmonic 6 emitted therefrom is restricted by means of an aperture 8. Consequently, an IR spectrum can be measured for a micro region smaller by a factor of 2 or 3 as compared with a conventional region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro-infrared spectrophotometer, and more particularly to a micro-infrared spectrophotometer capable of measuring an infrared absorption spectrum in a minute area.

[0002]

2. Description of the Related Art FIG. 2 shows an outline of a conventional method for measuring an infrared absorption spectrum (hereinafter abbreviated as IR spectrum) of a minute region, using a transmission method as an example. The IR spectrum of the minute region converges the infrared beam 22 having a wavelength of 2.5 to 25 μm emitted from the white light source 21 to some extent, transmits the infrared beam 22 to the sample 23, and includes the information of the sample. The infrared beam having the information other than the observation target area is excluded from the outer beam 24 by the aperture 26, and the beam 27 of the observation target area is removed.
It is obtained by detecting only the light with the detector 28, converting it into an electric signal and sending it to the data processor 29, and converting it into an IR spectrum.

[0003]

The limit of the diameter of the infrared beam that can be narrowed by the aperture depends on the wavelength of the beam.
If the beam has a wavelength of 10 μm, it is difficult to narrow the beam to 10 μmφ or less. In order to obtain a useful IR spectrum, an infrared beam having a continuous wavelength in the wavelength region of at least 2.5 to 14 μm is required, and in this case, the beam diameter that can be narrowed by the aperture is limited to about 14 μmφ. Therefore, there is a problem that an IR spectrum in a region smaller than that cannot be obtained. An object of the present invention is to solve such conventional problems.

[0004]

SUMMARY OF THE INVENTION The present invention provides an infrared light source for irradiating a sample with coherent infrared light, a detector for detecting a transmitted infrared beam transmitted through the sample, and a detector for detecting the transmitted infrared beam. A nonlinear optical material crystal, which is disposed between the nonlinear optical material crystal and a second or third harmonic by making the transmitted infrared beam incident thereon, Or, an aperture for narrowing down a third-order high-long wave is provided. Here, as the infrared light source, a variable wavelength infrared laser can be used.

[0005]

According to the present invention, a coherent light source such as a wavelength-tunable infrared laser is provided, a crystal of a nonlinear optical material is set in front of an aperture, an infrared beam containing information on a sample is transmitted, and a wavelength obtained therefrom is obtained. By narrowing the second harmonic of 1/2 or the third harmonic of 1/3 with an aperture, the limit of the beam diameter that can be narrowed is improved to 1/2 to 1/3 of the conventional one,
The IR spectrum of this minute region can be measured.

[0006]

EXAMPLES Next, examples of the present invention will be described with reference to FIG. 1, taking the case of the transmission method as an example. The apparatus comprises a light source 1 for irradiating a coherent infrared beam 2 to a sample 3 and a sample 3
Crystal 5 made of nonlinear optical material arranged on the detector side of
And an aperture 8 and a detector 10 arranged on the detector side of the crystal 5 of this nonlinear optical material. The coherent infrared beam 2 emitted from the light source 1 passes through the sample 3 and contains information on the sample. When the infrared beam 4 containing the information of this sample passes through the crystal 5 of the nonlinear optical material, the second or third harmonic wave 6 is obtained. The wavelength of the second or third harmonic 6 is 1/2 or 1/3 of the infrared beams 2 and 4. The area other than the observation area of the second or third harmonic 6 is excluded by the aperture 8 and the beam 9 of the observation area is removed.
Only lead to the detector 10. The beam 9 in the observation target area is converted into an electric signal by the detector 10 and sent to the data processing device 11 to be converted into an IR spectrum.

In order to utilize the nonlinear phenomenon, coherent light must be incident on the crystal of the nonlinear optical material. Moreover, in order to obtain an IR spectrum, 2.5 to 14
It is necessary to irradiate the sample with an infrared beam having a wavelength range of μm. Therefore, in the present invention, a variable wavelength infrared laser or the like is used as the light source 1, and the wavelength region of 2.5 to 14 μm is continuously swept. Thereby, the wavelength of the second or third harmonic obtained when the light passes through the crystal 5 of the nonlinear optical material is 1.25 to 7 μm, or 0.83 to 4.6.
7 μm, the limit that can be narrowed down by the aperture 8 is improved from 14 μmφ of the past to 7 μmφ or 4.67 μmφ, and the sample region where the IR spectrum can be obtained is from 7 μmφ of the conventional 14 μmφ or 4.67 μm
mφ, and an IR spectrum in a narrower region can be obtained.

[0008]

As described above, according to the present invention, it is possible to measure the IR spectrum in a minute region of 1/2 to 1/3 of the conventional one.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a microscopic infrared spectrophotometer according to the present invention.

FIG. 2 is a configuration diagram of an example of a conventional microscopic infrared spectrophotometer.

[Explanation of symbols]

 Reference Signs List 1 light source 2 infrared beam 3 sample 4 infrared beam containing information of sample 5 crystal of nonlinear optical material 6 second or third harmonic 8 aperture 9 beam in observation target area 10 detector 11 data processing device 21 light source 22 red External beam 23 Sample 24 Infrared beam including information of the sample 26 Aperture 27 Beam in observation area 28 Detector 29 Data processing device

Claims (2)

[Claims] 1. An infrared light source for irradiating a sample with coherent infrared light, a detector for detecting a transmitted infrared beam transmitted through the sample, and a detector arranged between the sample and the detector, A crystal of a nonlinear optical material that makes the transmitted infrared beam incident into a second or third harmonic, and an aperture arranged on the detector side of the nonlinear optical material to narrow down the second or third harmonic. And a microscopic infrared spectrophotometer. 2. The microscopic infrared spectrophotometer according to claim 1, wherein the infrared light source is a tunable infrared laser.