JP2013231707A - Circular dichroism measuring method and circular dichroism measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the circular dichroism of a sample more accurately and easily.SOLUTION: After a matrix element S02 of a Mueller matrix is measured by a circular dichroism measuring device 1A in Fig. 1(A), a matrix element S20 of the Mueller matrix is measured by a circular dichroism measuring device 1B in Fig. 1(B), and circular dichroism is calculated based thereupon. Consequently, artifact components included in a conventional measurement result of circular dichroism are removed and the circular dichroism can be measured more accurately. Further, more accurate circular dichroism was measured before in a solution state in which a sample does not have any optical activity other than circular dichroism, but the artifact components are suitably removed by this measuring method even for the circular dichroism of a sample in a state other than a solution state, for example, a solid-phase, a gel, a liquid-crystal, or a filmy state, so the method is applicable to measurement of circular dichroism of the sample not in the solution state.

Description

  The present invention relates to a circular dichroism measuring method and a circular dichroism measuring apparatus.

  Circular dichroism (CD) is a phenomenon caused by optical activity (chirality) of a molecule, and is defined as a difference in absorbance with respect to left and right circularly polarized light. Since this circular dichroism spectral information reflects the higher order structure of the molecule, it is often applied particularly to analysis of higher order structures of physiologically active substances. For this circular dichroism, a method is generally used in which a sample is irradiated with left and right circularly polarized light, and the difference in absorbance is obtained from the difference in intensity of transmitted light.

  Circular dichroism is measured only when the sample has an optical activity other than circular dichroism, i.e., has no dichroism or birefringence with respect to linearly polarized light, and the sample has optical activity other than circular dichroism. If so, this characteristic is known to be an artifact in circular dichroism measurement due to coupling with circular dichroism. Due to the influence of this artifact, the modulation method has not been suitable for the measurement of circular dichroism of samples having macroscopic anisotropy such as solids, films, and liquid crystals (for example, non-patented). Reference 1). For this reason, various studies for removing artifacts have been performed. For example, Patent Document 1 shows a process in which a sample is rotated by 45 °, an analyzer is removed, measurement is performed, and the sample is turned upside down, and then the average of these two signals is taken. .

Patent No. 4010760

Kamito, Spectroscopic Research, Vol.34, No.4, p.215 (1985) Y. Shindo, Optical Engineering, Vol.34, No.12, 3369 (1995) Ho.P.Jensen, J.A.Schellman, T.Troxell, Applied Spectroscopy, Vol.32, No.2, 192 (1978)

  However, according to the measurement apparatus described in Patent Document 1, since the optical system is complicated and the measurement method is complicated, it cannot be said that circular dichroism can be measured quickly and easily.

  The present invention has been made in view of the above, and an object of the present invention is to provide a circular dichroism measuring method and a circular dichroism measuring apparatus capable of measuring the circular dichroism of a sample more accurately and simply. And

  As a result of diligent research, the inventors measured the matrix elements S02 and S20 in the Mueller matrix in which the polarization characteristics such as the birefringence of the sample were quantified, and calculated circular dichroism based on the results. It has been found that more accurate and simple circular dichroism can be measured.

That is, in the circular dichroism measurement method according to the present invention, when the Mueller matrix related to the sample to be measured is represented by the following formula (A), the S02 measurement step for measuring the matrix element S02 and the following formula (A S20 measurement step for measuring the matrix element S20 in (2), and a calculation step for calculating circular dichroism from the matrix element S02 obtained in the S02 measurement step and the matrix element S20 obtained in the S20 measurement step, It is characterized by providing.

  And in said circular dichroism measuring method, said S02 measurement step injects the 1st light source which radiate | emits the light of a specific wavelength, the light radiate | emitted from the said 1st light source, and is a straight line of a 1st direction. A first polarizing plate capable of extracting first linearly polarized light that is polarized light and second linearly polarized light that is linearly polarized light in a second direction orthogonal to the first direction; and the first polarized light When the first linearly polarized light or the second linearly polarized light extracted from the plate is incident and the wavelength of the light from the first light source is λ, it has a vibration surface different from the vibration surface of the incident light and is orthogonal to each other. A first wave plate that emits with a phase difference of ¼λ between the two polarization components, and a first wave that is transmitted from the first wave plate and transmitted by the sample is converted into an electrical signal and detected. A first measuring device comprising: a light detecting means; A first step of taking out the first linearly polarized light by the polarizing plate and measuring the intensity of light transmitted through the sample; and measuring the intensity of the light taken out of the second linearly polarized light by the first polarizing plate and passing through the sample And the S20 measurement step includes: a second light source that emits light having the same wavelength as the first light source; and a transmission that is emitted from the second light source and transmitted by the sample. Light is incident, and out of the transmitted light, the phase difference between two polarization components having a vibration plane different from the vibration plane of the first linear polarization or the second linear polarization and orthogonal to each other is output as 1 / 4λ. And a second polarizing plate capable of taking out the linearly polarized light in the first direction and the linearly polarized light in the second direction by entering the light emitted from the second wavelength plate And the electric signal emitted from the second polarizing plate. A second step of measuring the light transmitted through the sample by taking out the first linearly polarized light by the second polarizing plate in a second measuring device comprising: A fourth step of taking out the second linearly polarized light by the second polarizing plate and measuring the light transmitted through the sample.

In addition, the circular dichroism measuring apparatus according to the present invention includes an S02 measuring unit that measures the matrix element S02 when the Mueller matrix related to the sample to be measured is represented by the following formula (B), and the following formula (B S20 measuring means for measuring the matrix element S20 in (2), a calculating means for calculating circular dichroism from the matrix element S02 obtained by the S02 measuring means and the matrix element S20 obtained by the S20 measuring means, It is characterized by having.

  In the circular dichroism measuring device, the first measuring device functioning as the S02 means receives a first light source that emits light of a specific wavelength, and light emitted from the first light source, A first polarizing plate capable of extracting first linearly polarized light that is linearly polarized light in a first direction and second linearly polarized light that is linearly polarized light in a second direction orthogonal to the first direction; When the first linearly polarized light or the second linearly polarized light extracted from the first polarizing plate is incident and the wavelength of the light from the first light source is λ, the vibration is different from the vibration surface of the incident light. A first wave plate that emits a phase difference between two orthogonally polarized light components having a plane of ¼λ, and the transmitted light that is emitted from the first wave plate and transmitted by the sample is converted into an electrical signal. And first light detection means for detecting, and measuring the S20 The second measuring device functioning as a means receives a second light source that emits light having the same wavelength as the first light source, and transmitted light that is emitted from the second light source and transmitted by the sample, and transmits the transmitted light. A second wave plate that emits a phase difference between two polarization components orthogonal to each other and having a vibration plane different from that of the first linear polarization or the second linear polarization of light; A second polarizing plate capable of taking out light emitted from the second wave plate and taking out linearly polarized light in the first direction and linearly polarized light in the second direction; and the second polarizing plate And a second light detecting means for detecting by converting into an electric signal emitted from.

  According to the research by the inventors, after obtaining the matrix element S02 and the matrix element S20 of the Mueller matrix, and calculating the circular dichroism based on the matrix element S02 and the matrix element S20, the conventional circular dichroism measurement result is obtained. Was found to remove the included artifact components. Therefore, based on the above circular dichroism measurement method and circular dichroism measurement device, the matrix element S02 is measured using the first measurement device, the matrix element S20 is measured using the second measurement device, and By adopting a configuration in which circular dichroism is calculated using these results, more accurate circular dichroism can be measured. In addition, conventionally, in order to measure more accurate circular dichroism, measurement has been performed in a solution state that is a state having no optical activity other than circular dichroism. In other states than the solution state, for example, the circular dichroism of the solid sample, gel, liquid crystal, and film sample, the artifact component is properly removed, so the circular dichroism of the sample that is not in the solution state. It can be applied to sex measurement.

  Here, the first measurement apparatus includes a turntable on which the first polarizing plate, the first wave plate, and the sample are placed, and the first measurement device before the rotation is rotated when the turntable is rotated. The first polarizing plate, the first wave plate, and the sample are placed at a position that overlaps an optical path of light from a light source, and the second measurement device rotates the turntable in the first measurement device. It can be set as the aspect characterized by comprising.

  In the above circular dichroism measuring device, more accurate circular dichroism measurement from which artifact components are removed can be performed. In the case of a circular dichroism device, the arrangement of the optical component and the sample is changed by rotating the turntable, so that measurement can be performed more easily. In addition, compared to the case where the arrangement is changed manually, the position and orientation of each part and sample can be accurately arranged along the optical axis, so circular dichroism can be measured more accurately. be able to.

  The first measuring device includes a turntable on which the first light source and the photodetector are placed, and a partition is provided between the first light source and the photodetector in the turntable. The optical path of the light from the first light source and the optical path of the light incident on the first light detection means are provided at positions that overlap each other when the turntable is rotated, and the second measuring device is The embodiment can be configured by rotating the turntable in the first measuring device.

  In the above circular dichroism measuring device, more accurate circular dichroism measurement from which artifact components are removed can be performed. In the case of a circular dichroism device, the arrangement of the optical component and the sample is changed by rotating the turntable, so that measurement can be performed more easily. In addition, compared to the case where the arrangement is changed manually, the position and orientation of each part and sample can be accurately arranged along the optical axis, so circular dichroism can be measured more accurately. be able to. In addition, since a series of measurements can be performed without moving the sample, it is also possible to measure a sample that is mechanically unstable, such as fragile or easily collapsed.

  Further, in place of the first wave plate or the second wave plate, when the wavelength of light from the first light source is λ, two vibration surfaces different from the vibration surface of the incident light are orthogonal to each other. It is also possible to use an optical phase modulation unit that periodically modulates the phase difference between the polarization components and emits the light after the phase difference modulation. When the phase modulation means is used, the measurement of the matrix element S02 or the matrix element S20 can be performed without changing the direction of the polarizing plate, etc., so that the measurement can be performed more easily.

  Further, the first light source or the second light source may be configured to include a spectroscopic unit that splits and emits light having a specific wavelength from light having a plurality of wavelengths. When configured to include a spectroscopic means, the wavelength of light from the light source can be easily switched, so that circular dichroism measurement under various conditions can be performed more easily.

  As another aspect of the circular dichroism measuring method according to the present invention, the S02 measuring step includes a first light source that emits light of a specific wavelength, and light emitted from the first light source, A first polarizing plate capable of extracting first linearly polarized light that is linearly polarized light in a first direction and second linearly polarized light that is linearly polarized light in a second direction orthogonal to the first direction; When the first linearly polarized light or the second linearly polarized light extracted from the first polarizing plate is incident and the wavelength of the light from the first light source is λ, the vibration is different from the vibration surface of the incident light. A first wave plate that emits a phase difference between two orthogonally polarized light components having a plane of ¼λ, and the transmitted light that is emitted from the first wave plate and transmitted by the sample is converted into an electrical signal. And a first light detecting means for detecting the first measuring device. The first step of taking out the first linearly polarized light by the first polarizing plate and measuring the intensity of the light passing through the sample, and taking out the second linearly polarized light by the first polarizing plate and passing through the sample A second step of measuring intensity, wherein the S20 measuring step emits linearly polarized light in the first direction and linearly polarized light in the second direction, which has the same wavelength as the first light source. A possible third light source, and a transmitted light that is emitted from the third light source and transmitted by the sample is incident, and of the transmitted light, the vibration surface of the first linearly polarized light or the second linearly polarized light is A third wavelength plate that emits a phase difference between two polarization components that have different vibration planes and are orthogonal to each other, and the light emitted from the third wavelength plate is incident, and the first direction And linearly polarized light in the second direction are extracted. In a third measuring apparatus, comprising: a third polarizing plate capable of being converted into an electric signal emitted from the third polarizing plate; A third step of measuring linearly polarized light in the first direction from the third polarizing plate, measuring light transmitted through the sample, and from the third light source, A fourth step of emitting linearly polarized light in a second direction, extracting linearly polarized light in the first direction from the third polarizing plate, and measuring light transmitted through the sample; and the third light source A fifth step of measuring linearly polarized light in the first direction from the third polarizing plate, taking out the linearly polarized light in the second direction from the third polarizing plate, and measuring light transmitted through the sample; The third polarized light is emitted from the three light sources in the second direction. A sixth step of taking out linearly polarized light in the second direction from the plate and measuring light transmitted through the sample.

  Further, instead of the first measuring device, a fourth light source having the same wavelength as the first light source and capable of emitting linearly polarized light in the first direction and linearly polarized light in the second direction, When linearly polarized light from four light sources is incident and the wavelength of light from the fourth light source is λ, the phase difference between two polarization components that have a vibration plane different from that of the incident light and are orthogonal to each other is obtained. A fourth wavelength plate that emits as ¼λ, and linearly polarized light in the first direction and linearly polarized light in the second direction are extracted from the transmitted light that is emitted from the fourth wavelength plate and transmitted by the sample. And a fourth measuring device including a fourth polarizing plate capable of detecting the light output from the fourth polarizing plate by converting the light emitted from the fourth polarizing plate into an electrical signal, and the S02 measuring step includes: The linearly polarized light in the first direction is emitted from the fourth light source, and the fourth light source An eleventh step of taking out linearly polarized light in the first direction from the polarizing plate and measuring light transmitted through the sample; and emitting linearly polarized light in the second direction from the fourth light source; Taking out the linearly polarized light in the first direction from the fourth polarizing plate and measuring the light transmitted through the sample; and emitting the linearly polarized light in the first direction from the fourth light source. Taking out the linearly polarized light in the second direction from the fourth polarizing plate and measuring the light transmitted through the sample; and emitting the linearly polarized light in the second direction from the fourth light source. And a fourteenth step of taking out linearly polarized light in the second direction from the fourth polarizing plate and measuring light transmitted through the sample.

  Further, as another aspect of the circular dichroism measuring device according to the present invention, the first measuring device constituting the S02 measuring means emits light of a specific wavelength. The first light source, the light emitted from the first light source, the first linearly polarized light that is linearly polarized light in the first direction, and the straight line in the second direction orthogonal to the first direction. A first polarizing plate capable of taking out the second linearly polarized light, which is polarized light, and the first linearly polarized light or the second linearly polarized light taken out from the first polarizing plate is incident on the first polarizing plate. A first wavelength plate that emits a phase difference between two polarization components orthogonal to each other and having a vibration plane different from the vibration plane of incident light, where λ is the wavelength of the light of the first light; The transmitted light emitted from the wave plate and transmitted by the sample is converted into an electrical signal and detected. A third measuring device comprising the first light detecting means that emits light and having the same wavelength as that of the first light source, wherein the S20 measuring means comprises the linearly polarized light in the first direction and the second direction. A third light source capable of emitting linearly polarized light, and transmitted light which is emitted from the third light source and transmitted by the sample, and the first linearly polarized light or the second linearly polarized light among the transmitted light is incident. A third wavelength plate that emits a phase difference between two polarization components having a vibration plane different from the vibration plane of ¼λ, and light emitted from the third wavelength plate is incident; A third polarizing plate capable of extracting linearly polarized light in the first direction and linearly polarized light in the second direction; and third light detected by converting into an electric signal emitted from the third polarizing plate And a detection means.

  Further, instead of the first measuring device, a fourth light source having the same wavelength as the first light source and capable of emitting linearly polarized light in the first direction and linearly polarized light in the second direction, When linearly polarized light from four light sources is incident and the wavelength of light from the fourth light source is λ, the phase difference between two polarization components that have a vibration plane different from that of the incident light and are orthogonal to each other is obtained. A fourth wavelength plate that emits as ¼λ, and linearly polarized light in the first direction and linearly polarized light in the second direction are extracted from the transmitted light that is emitted from the fourth wavelength plate and transmitted by the sample. It is also possible to adopt an aspect including a fourth measuring device including a fourth polarizing plate capable of being converted and a fourth light detecting unit that converts the light emitted from the fourth polarizing plate into an electric signal and detects the electric signal. .

  According to the research by the inventors, when obtaining the matrix element S02 and the matrix element S20 of the Mueller matrix, the circular dichroism is calculated as described above by using linearly polarized light. Thus, the artifact component is removed more effectively and the measurement can be performed more accurately. The linearly polarized light is used for calculating both the matrix elements S02 and S20, so that the artifact component can be more effectively removed, and more accurate circular dichroism can be measured.

  ADVANTAGE OF THE INVENTION According to this invention, the circular dichroism measuring method and the circular dichroism measuring apparatus which can measure the circular dichroism of a sample more correctly and simply are provided.

It is a figure explaining the structure of the circular dichroism measuring device which concerns on 1st Embodiment. It is a figure explaining the 1st composition of the circular dichroism measuring device concerning a 2nd embodiment. It is a figure explaining the 2nd structure of the circular dichroism measuring device concerning a 2nd embodiment. It is a figure explaining the 1st structure of the circular dichroism measuring device which concerns on 3rd Embodiment. It is a figure explaining the 2nd structure of the circular dichroism measuring device concerning a 3rd embodiment. It is a figure explaining the structure of the circular dichroism measuring device which concerns on 4th Embodiment. It is a figure explaining the structure of the circular dichroism measuring device which concerns on 5th Embodiment. It is a figure explaining the structure of the circular dichroism measuring device which concerns on 6th Embodiment. It is a figure explaining the structure of the circular dichroism measuring device which concerns on 7th Embodiment. It is a figure explaining the structure of the circular dichroism measuring device which concerns on 8th Embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.
(First embodiment)

  1A and 1B are schematic configuration diagrams illustrating the configuration of a circular dichroism measuring apparatus according to the first embodiment of the present invention. The circular dichroism measuring apparatus 1A (first measuring apparatus / S02 measuring means) shown in FIG. 1A includes a light source 10, a monochromatic filter 20, a polarizing plate 30, a 1 / 4λ wavelength plate 40, and a photodetector 50 as light sources. 10 is arranged in this order along the optical axis from 10, and the sample 100 is arranged on the optical path between the quarter-wave plate 40 and the photodetector 50.

  The light source 10 emits light for irradiating the sample. The light emitted from the light source 10 is non-polarized light. For example, a deuterium lamp that emits light having a wavelength of 280 nm is used as the light source 10.

  The light emitted from the light source 10 passes through the monochromatic filter 20 and enters the polarizing plate 30. The monochromatic filter 20 is provided to remove wavelength components, noise components, and the like that are not necessary for circular dichroism measurement. In the circular dichroism measuring apparatus 1A of the present embodiment, a monochromatic filter 20 that allows light having a wavelength of 280 nm to pass therethrough is used. The polarizing plate 30 extracts linearly polarized light from the light emitted from the light source 10. For example, a Grand Taylor prism is used as the polarizing plate 30.

  Here, in the circular dichroism measuring apparatus 1A, the optical axis of light from the light source 10 is defined as a Z axis, and two axes perpendicular to the Z axis and orthogonal to each other are defined as an X axis and a Y axis, respectively. Here, it is assumed that the polarizing plate 30 extracts linearly polarized light in the direction of 0 ° with respect to the X axis.

  The quarter-wave plate 40 is arranged in a state rotated by 45 ° around the Z axis with respect to the X axis. When the linearly polarized light that has passed through the polarizing plate 30 passes through the quarter-wave plate 40, the polarization component having the vibration plane orthogonal to the vibration plane of the linearly polarized light has the same vibration plane as that of the linear polarization. The phase difference is set to 1 / 4λ (π / 2) with respect to the polarization component. As a result, the light that has passed through the ¼λ wavelength plate 40 is converted into right circularly polarized light or left circularly polarized light and is emitted.

  The photodetector 50 has a function of converting the transmitted light emitted from the ¼λ wavelength plate 40 and transmitted through the sample 100 into an electrical signal. In the measurement of circular dichroism, the electric signal detected by the photodetector 50 is used to determine the difference between the signal with right circular polarization and the signal with left circular polarization, and the calculation result is obtained, for example, as a circular dichroism image. As a result, the measurement result can be obtained.

  In addition, the circular dichroism measuring device 1B (second measuring device / S20 measuring means) shown in FIG. 1B includes a light source 10, a monochromatic filter 20, a 1 / 4λ wavelength plate 40, a polarizing plate 30, and a photodetector 50. Are arranged in this order along the optical axis from the light source 10, and the sample 100 is arranged on the optical path between the monochromatic filter 20 and the ¼λ wavelength plate 40. That is, as compared with the circular dichroism measuring apparatus 1A shown in FIG. 1A, the arrangement order of the polarizing plate 30 and the 1 / 4λ wavelength plate 40 along the optical axis is reversed, and the sample 100 Is different from that of the quarter-wave plate 40.

  In this circular dichroism measuring apparatus 1 </ b> B, the light emitted from the light source 10 passes through the monochromatic filter 20 and is then irradiated onto the sample 100. Of these, the light transmitted through the sample passes through the ¼λ wavelength plate 40 and is converted into circularly polarized light, and then the light that has passed through the polarizing plate 30 is converted into an electrical signal by the photodetector 50.

  In the circular dichroism measurement according to the present embodiment, the circular dichroism is measured more accurately and easily by measuring the circular dichroism using the circular dichroism measuring devices 1A and 1B. It becomes possible to do. This will be described below.

First, artifacts that occur in circular dichroism measurement will be described. According to the above-mentioned Patent Document 1, the Mueller matrix of a sample having optical activity is represented by the following formula (1).

In the above formula (1), CD is circular dichroism, CB is circular polarization birefringence, LD is linear polarization dichroism, LB is linear polarization birefringence, and θ is the rotation angle of the sample with respect to the X axis. Yes. In addition, when “′” is added to the word indicating each characteristic in the mathematical formula (1), it describes the case where the sample is inclined by 45 °. Hereinafter, the above mathematical formula (1) is omitted as represented by the mathematical formula (2). Note that the coefficient e- ^Ae of the matrix described in Equation (1) is omitted because it is a coefficient that does not affect the following examination.

When left circularly polarized light or right circularly polarized light is irradiated to the sample described in Equation (2), the Stokes vector of the transmitted light that has passed through the sample is the Mueller matrix S (θ) and the circularly polarized Stokes vector. It can be obtained by product. The result is expressed as Equation (3) for left circularly polarized light and Equation (4) for right circularly polarized light.

Here, since the light intensity is expressed by the first term of the Stokes vector, the transmitted light intensity with respect to the left circularly polarized light is known as S00-S02 based on the equation (3), and the transmitted light intensity with respect to the right circularly polarized light is expressed by the equation Based on (4), it is known as S00 + S02. Since the circular dichroism is a difference between the transmitted light intensity of the left circularly polarized light and the transmitted light intensity of the right circularly polarized light, the circular dichroism is obtained as shown by the equation (5).

  In the formula (5), the difference between the transmitted light intensity of the left circularly polarized light and the transmitted light intensity of the right circularly polarized light is not only the CD (circular dichroism) component but also the LD (linearly polarized dichroic). And components derived from LB (linearly polarized birefringence). When the product of LD and LB is small enough to be ignored as compared with CD, information on pure circular dichroism that does not include a linearly polarized light component can be obtained. However, when the product of LD and LB is a size that cannot be ignored compared to CD, it cannot be said that pure circular dichroism has been measured and is affected by artifacts. There is.

By the way, although the above formula (1) is shown as a Mueller matrix of a sample having optical activity in Patent Document 1, in Non-Patent Document 2, the description of the Mueller matrix is shown in Formula (6). The numerical formula (1) in Patent Document 1 is partially different from the reference numerals and symbols.

  For example, the matrix element S02 is “CD + 1/2 (LB′LD−LBLD ′)” in Patent Document 1, but is “CD + 1/2 (LB′LD + LBLD ′)” in Non-Patent Document 2. . Thus, if the basic Mueller matrix is not accurate, further discussion will be difficult. For this reason, the inventor newly obtained a Mueller matrix based on the Mueller matrix derivation method described in Non-Patent Documents 2 and 3.

According to Non-Patent Document 3, the general formula of the Mueller matrix is expressed by the following formulas (7) and (8).

When the above mathematical formula is expanded, mathematical formulas (9) and (10) are obtained.

Further, when the above formulas (9) and (10) are expanded to the second order term according to Non-Patent Document 2, the following formula (11) is obtained.

Of the parameters included in Equation (11), CD and CB are about 10 ⁻³ to 10 ⁻⁵ smaller than LD and LB, so that the square terms of CD and CB can be ignored. As a result of simplifying Equation (11), Equation (12) is obtained.

Here, when the rotation angle of the sample is θ, the Mueller matrix considering the rotation of the sample can be expressed by the following formula (13).

R in the equation (13) is a matrix for rotation, and is represented by the following equation (14). R-1 is an inverse matrix of R and is represented by Equation (15).

As a result, the matrix element S02 of the Mueller matrix is expressed by Equation (16), and S20 is expressed by Equation (17).

Here, when the polarizing plate 30 is arranged so that the polarization axis is in the X-axis direction using the circular dichroism measuring apparatus 1A according to the present embodiment, the Stokes vector of the transmitted light from the sample is expressed by the following equation: It is derived by the calculation of (18).

In this case, the intensity of the light detected by the photodetector 50 of the circular dichroism measuring apparatus 1A is the first term of Expression (18), that is, Expression (19).

Next, when the polarizing plate 30 is arranged so that the polarization axis is in the Y-axis direction, the Stokes vector of the transmitted light from the sample is derived by the calculation of the following formula (20).

In this case, the intensity of the light detected by the photodetector 50 of the circular dichroism measuring apparatus 1A is the first term of Expression (20), that is, Expression (21).

Here, when the equation (19) is subtracted from the equation (21), only the matrix element S02 is obtained as shown by the equation (22), and thus the above calculation result, S02, is obtained.

  That is, by using the circular dichroism measuring apparatus 1A, the quarter-wave plate 40 that forms the linearly polarized light having the first vibration plane that has passed through the polarizing plate 30 with an angle of 45 ° with respect to the first vibration plane. The first measurement result obtained by irradiating the sample with circularly polarized light obtained by being incident on the sample and the arrangement of the polarizing plate 30 by 90 ° with respect to the ¼λ wavelength plate 40 And a second measurement result obtained by irradiating the sample with circularly polarized light having a second vibration surface perpendicular to the first vibration surface, and a matrix of a Mueller matrix. Element S02 can be determined.

Next, assuming the case where measurement is performed using the circular dichroism measuring device 1B in which the arrangement of the polarizing plate 30, the 1 / 4λ wavelength plate 40, and the sample 100 is changed, the same as the circular dichroic device 1A is assumed. Perform the calculation. First, when the polarizing plate 30 is arranged so that the polarization axis is in the X-axis direction, the Stokes vector of the transmitted light from the sample is derived by the calculation of the following formula (23).

In this case, the intensity of the light detected by the photodetector 50 of the circular dichroism measuring apparatus 1B is the first term of Expression (23), that is, Expression (24).

Next, when the polarizing plate 30 is arranged so that the polarization axis is in the Y-axis direction, the Stokes vector of the transmitted light from the sample is derived by calculation of the following formula (25).

In this case, the intensity of the light detected by the photodetector 50 of the circular dichroism measuring device 1A is the first term of Expression (25), that is, Expression (26).

Here, when the formula (26) is subtracted from the formula (25), only the matrix element S20 is obtained as shown by the formula (27), and thus the above calculation result, S20, is obtained.

  That is, the light emitted from the light source 10 and transmitted through the sample 100 is made incident on the 1 / 4λ wavelength plate 40 using the circular dichroism measuring apparatus 1B, and the light emitted from the 1 / 4λ wavelength plate 40 is emitted. Is obtained by allowing the light having the first vibration surface to pass through and detecting the light by the photodetector 50. A third measurement result and a fourth obtained by detecting light having a second vibration surface orthogonal to the first vibration surface by the photodetector 50 by rotating the arrangement of the polarizing plate 30 by 90 °. The matrix element S20 of the Mueller matrix can be obtained based on the measurement result.

By the way, as shown in the mathematical expressions (16) and (17), the matrix elements S02 and S20 are obtained by adding S02 and S20 because the terms derived from the linearly polarized light, that is, the signs of the artifact components are reversed. By combining them, the artifact component can be canceled as shown in Equation (28), and as a result, a pure circular dichroism measurement result can be obtained.

  As described above, according to the circular dichroism measuring apparatus and the circular dichroism measuring method according to the present embodiment, after obtaining the matrix element S02 and the matrix element S20 of the Mueller matrix, respectively, The chromaticity is calculated. For this reason, since the artifact component contained in the conventional circular dichroism measurement result is removed, more accurate circular dichroism measurement can be performed. In addition, conventionally, in order to measure more accurate circular dichroism, measurement has been performed in a solution state that is a state having no optical activity other than circular dichroism. In other states than the solution state, for example, the circular dichroism of the solid sample, gel, liquid crystal, and film sample, the artifact component is properly removed, so the circular dichroism of the sample that is not in the solution state. It can be applied to sex measurement.

  Although the case where the polarizing plate 30 is rotated by 90 ° has been described above, the same effect can be obtained even when the wave plate 40 is rotated by 90 °.

(Second Embodiment)
Next, the configuration of the circular dichroism measuring apparatus according to the second embodiment of the present invention will be described. 2 and 3 are schematic configuration diagrams illustrating the configuration of the circular dichroism measuring apparatus according to the second embodiment of the present invention. The circular dichroism measuring device according to the second embodiment is different from the circular dichroism measuring device according to the first embodiment in that the polarizing plate 30, the quarter-wave plate 40, and the sample 100 are on the turntable 60. These are arranged so that they can be rotated by the rotation of the turntable 60.

  A circular dichroism measuring device 2A shown in FIG. 2 has a configuration corresponding to the circular dichroism measuring device 1A shown in FIG. 1A, and includes a light source 10, a monochromatic filter 20, a polarizing plate 30, and a 1 / 4λ wavelength. The plate 40 and the photodetector 50 are arranged in this order along the optical axis from the light source 10, and the sample 100 is arranged on the optical path between the ¼λ wavelength plate 40 and the photodetector 50. As in the first embodiment, if the optical axis of light from the light source 10 is the Z axis, and two axes perpendicular to the Z axis and perpendicular to each other are the X axis and the Y axis, respectively, the polarizing plate 30, The quarter-wave plate 40 and the sample 100 are disposed on the turntable 60, and the turntable 60 can rotate around the X axis. Further, the polarizing plate 30 and the quarter-wave plate 40 are rotatable around the optical axis, and can be rotated around the X axis similarly to the turntable 60.

  The circular dichroism measuring device 2B shown in FIG. 3 has a configuration corresponding to the circular dichroism measuring device 1B of FIG. 1B, and rotates the turntable 60 of the circular dichroism measuring device 2A by 180 °. It is a thing. In this configuration, the light source 10, the monochromatic filter 20, the 1 / 4λ wavelength plate 40, the polarizing plate 30, and the photodetector 50 are arranged in this order along the optical axis from the light source 10, and the monochromatic filter 20 and the 1 / 4λ wavelength plate are arranged. A sample 100 is arranged on the optical path between the two.

  A method for performing measurement using the circular dichroism measuring devices 2A and 2B will be described. First, in the circular dichroism measuring apparatus 2A shown in FIG. 2, the 1 / 4λ wavelength plate 40 is disposed in a state rotated by 45 ° around the Z axis with respect to the X axis, and the polarization axis of the polarizing plate 30 is set in the X axis direction. And In this state, the light intensity corresponding to 1/2 (S00-S02) shown in Equation (19) is acquired. Next, by rotating the polarizing plate 30, the polarization axis is set to the Y-axis direction, and the intensity of light corresponding to 1/2 (S00 + S02) shown in Equation (21) is acquired. From these results, the matrix element S02 of the sample Mueller matrix can be obtained.

  Next, the turntable 60 is rotated 180 ° to obtain the arrangement of the circular dichroism measuring device 2B shown in FIG. Further, the 1 / 4λ wavelength plate 40 is also rotated by 90 ° around the optical axis, so that the arrangement of the 1 / 4λ wavelength plate 40 is made the same as that of the circular dichroism measuring apparatus 1B of FIG. The quarter-wave plate 40 is disposed in a state rotated by 45 ° around the Z axis with respect to the X axis, and the polarization axis of the polarizing plate 30 is set to the X axis direction. In this state, the intensity of light corresponding to 1/2 (S00 + S20) shown in Expression (24) is acquired. Next, by rotating the polarizing plate 30, the polarization axis is set to the Y-axis direction, and the light intensity corresponding to 1/2 (S00-S20) shown in Equation (26) is acquired. From these results, the matrix element S20 of the Mueller matrix of the sample can be obtained.

  Finally, by adding the matrix elements S02 and S20 of the Mueller matrix obtained as a result of the above calculation, an accurate circular dichroism signal can be obtained as shown in Expression (28).

  As described above, according to the circular dichroism measuring apparatus according to the second embodiment, as in the first embodiment, more accurate circular dichroism measurement from which artifact components are removed can be performed. Further, in comparison with the first embodiment, in the case of the circular dichroism device according to the second embodiment, the arrangement of the optical components and the sample is changed by rotating the turntable 60, so that the measurement can be performed more easily. it can. In addition, compared to the case where the arrangement is changed manually, the position and orientation of each part and sample can be accurately arranged along the optical axis, so circular dichroism can be measured more accurately. be able to.

(Third embodiment)
Next, the configuration of the circular dichroism measuring apparatus according to the third embodiment of the present invention will be described. 4 and 5 are schematic configuration diagrams illustrating the configuration of the circular dichroism measuring apparatus according to the third embodiment of the present invention. The circular dichroism measuring device according to the third embodiment is different from the circular dichroism measuring device according to the second embodiment in that the light source 10, the monochromatic filter 20, This is the photodetector 50, which can be rotated by the rotation of the turntable 60. Further, since the light source 10 which is the most upstream of the optical system and the photodetector 50 which is the most downstream are arranged on the turntable 60, the light traveling direction is changed by the mirrors 81 to 84.

  A circular dichroism measuring device 3A shown in FIG. 4 has a configuration corresponding to the circular dichroism measuring device 1A shown in FIG. In the circular dichroism measuring device 3A, the light source 10, the monochromatic filter 20, the polarizing plate 30, the ¼λ wavelength plate 40, and the photodetector 50 are arranged in this order along the optical axis from the light source 10, and 1 / A sample 100 is disposed on the optical path between the 4λ wavelength plate 40 and the photodetector 50. In addition, mirrors 81 to 84 are disposed on the optical path.

  When the axis on which the polarizing plate 30, the 1 / 4λ wavelength plate 40 and the sample 100 are placed is the Z axis, and two axes perpendicular to the Z axis and orthogonal to each other are the X axis and the Y axis, respectively, the light source 10. The monochromatic filter 20 and the photodetector 50 are arranged on a turntable 60, and the turntable 60 can rotate around the X axis. On the turntable 60, the light source 10 and the monochromatic filter 20 side and the photodetector 50 side are separated by a partition wall 70. The polarizing plate 30 and the ¼λ wavelength plate 40 are rotatable around the optical axis, and can be rotated around the X axis similarly to the turntable 60.

  A circular dichroism measuring device 2B shown in FIG. 5 has a configuration corresponding to the circular dichroism measuring device 1B of FIG. 1B, and rotates the turntable 60 of the circular dichroism measuring device 3A by 180 °. It is a thing. In this configuration, the light source 10, the monochromatic filter 20, the 1 / 4λ wavelength plate 40, the polarizing plate 30, and the photodetector 50 are arranged in this order along the optical axis from the light source 10, and the monochromatic filter 20 and the 1 / 4λ wavelength plate are arranged. A sample 100 is arranged on the optical path between the two.

  A method for performing measurement using the circular dichroism measuring devices 3A and 3B will be described. First, in the circular dichroism measuring apparatus 3A shown in FIG. 4, the 1 / 4λ wavelength plate 40 is disposed in a state rotated by 45 ° around the Z axis with respect to the X axis, and the polarization axis of the polarizing plate 30 is set in the X axis direction. And When light is emitted from the light source 10 with this configuration, the light from the light source 10 travels in the negative direction of the Z axis through the monochromatic filter 20, and then its path is changed to the negative direction of the Y axis due to reflection by the mirror 81. In addition, it is changed in the Z-axis direction by reflection at the mirror 82. Thereafter, the light that has passed through the polarizing plate 30, the ¼λ wavelength plate 40, and the sample 100 travels in the Y-axis direction through the mirror 83, further travels in the −Z-axis direction by the mirror 84, and enters the photodetector 50. . In this state, the light intensity corresponding to 1/2 (S00-S02) shown in Equation (19) can be acquired. Next, by rotating the polarizing plate 30, the polarization axis is set to the Y-axis direction, and the intensity of light corresponding to 1/2 (S00 + S02) shown in Equation (21) is acquired. From these results, the matrix element S02 of the sample Mueller matrix can be obtained.

  Next, the turntable 60 is rotated 180 ° to obtain the arrangement of the circular dichroism measuring device 3B shown in FIG. Further, the 1 / 4λ wavelength plate 40 is also rotated by 90 ° around the optical axis, so that the arrangement of the 1 / 4λ wavelength plate 40 is made the same as that of the circular dichroism measuring apparatus 1B of FIG. The quarter-wave plate 40 is disposed in a state rotated by 45 ° around the Z axis with respect to the X axis, and the polarization axis of the polarizing plate 30 is set to the X axis direction. In this state, the light emitted from the light source 10 travels in the Z-axis direction through the monochromatic filter 20, and then its path is changed in the Y-axis direction by reflection at the mirror 84. The direction is changed in the negative direction. Thereafter, the light that has passed through the sample 100, the quarter-wave plate 40, and the polarizing plate 30 travels in the negative Y-axis direction through the mirror 82, further travels in the Z-axis direction by the mirror 81, and enters the photodetector 50. . In this state, the intensity of light corresponding to 1/2 (S00 + S20) shown in Expression (24) is acquired. Next, by rotating the polarizing plate 30, the polarization axis is set to the Y-axis direction, and the light intensity corresponding to 1/2 (S00-S20) shown in Equation (26) is acquired. From these results, the matrix element S20 of the Mueller matrix of the sample can be obtained.

  Finally, by adding the matrix elements S02 and S20 of the Mueller matrix obtained as a result of the above calculation, an accurate circular dichroism signal can be obtained as shown in Expression (28).

  As described above, according to the circular dichroism measuring apparatus according to the third embodiment, as in the first embodiment, more accurate circular dichroism measurement from which artifact components are removed can be performed. Further, in comparison with the first embodiment, in the case of the circular dichroism device according to the third embodiment, the arrangement of the optical components and the sample is changed by rotating the turntable 60, so that the measurement can be performed more easily. it can. In addition, compared to the case where the arrangement is changed manually, the position and orientation of each part and sample can be accurately arranged along the optical axis, so circular dichroism can be measured more accurately. be able to. In addition, since the measurement can be performed without moving the sample 100, it is possible to perform measurement on a sample that is mechanically unstable, such as fragile or easy to fall.

(Fourth embodiment)
Next, the configuration of the circular dichroism measuring apparatus according to the fourth embodiment of the present invention will be described. FIG. 6 is a schematic configuration diagram illustrating the configuration of a circular dichroism measuring apparatus according to the fourth embodiment of the present invention. The circular dichroism measuring apparatus according to the fourth embodiment is different from the circular dichroism measuring apparatus according to the third embodiment in that a spectroscope 21 is used instead of the monochromatic filter 20, and 1 / 4λ. The circular polarization modulator 11 is used instead of the wave plate 40. In the circular dichroism measuring apparatus according to this embodiment, a lock-in amplifier 91 and a recorder 92 that receive optical signals from the circular polarization modulator 45 and the photodetector 50 are connected.

  The circular dichroism measuring device 4 shown in FIG. 6 has a configuration corresponding to the circular dichroism measuring device 1A shown in FIG. In the circular dichroism measuring device 4, the light source 10, the spectroscope 21, the polarizing plate 30, the circular polarization modulator 45, and the photodetector 50 are arranged in this order along the optical axis from the light source 10, and circular polarization modulation is performed. A sample 100 is disposed on the optical path between the detector 45 and the photodetector 50. In addition, mirrors 81 to 84 are disposed on the optical path. The spectroscope 21 receives light from the light source 10 and outputs only light having a specific wavelength. The circularly polarized light modulator 45 has a function of inputting light from the light source 10 and periodically converting it into right circularly polarized light or left circularly polarized light. The circular polarization modulator 45 modulates the linearly polarized light included in the light incident from the light source 10 so that the phase difference between the two polarization components orthogonal to each other changes periodically. The light is alternately converted into left circularly polarized light and emitted. As a specific element of the circular polarization modulator 45, for example, a photoelastic modulator (PEM) can be used. In addition, a modulation signal indicating a modulation period in the circular polarization modulator 45 is transmitted to the lock-in amplifier 91. At the same time, the light signal received by the photodetector 50 is also transmitted to the lock-in amplifier 91. A recorder 92 is connected to the lock-in amplifier 91. The recorder 92 has a function of storing information acquired by the lock-in amplifier 91 and can be realized by using, for example, an AD converter and a computer.

  Further, in the circular dichroism measuring device 4, an axis on which the polarizing plate 30, the circular polarization modulator 45 and the sample 100 are placed is a Z axis, and two axes perpendicular to the Z axis and perpendicular to each other are Assuming that the X axis and the Y axis are respectively set, the light source 10, the spectroscope 21, and the photodetector 50 are disposed on the turntable 60, and the turntable 60 can rotate around the X axis. On the turntable 60, the light source 10 and the monochromatic filter 20 side and the photodetector 50 side are separated by a partition wall 70. The polarizing plate 30 and the ¼λ wavelength plate 40 are rotatable around the optical axis, and can be rotated around the X axis similarly to the turntable 60. 6 shows a configuration corresponding to the circular dichroism measuring device 3B in FIG. 5, but the configuration of the circular dichroism measuring device 3A in FIG. 4 is obtained by rotating the turntable 60. You can also.

  A method for performing measurement using the circular dichroism measuring device 4A will be described. First, the turntable 60 is rotated 180 ° to have a configuration corresponding to the circular dichroism measuring apparatus 3A, the circular polarization modulator 45 is operated, and right circularly polarized light and left circularly polarized light are emitted alternately and periodically. With this configuration, in the photodetector 50, the light intensity corresponding to 1/2 (S00-S02) shown in Equation (19) and 1/2 (S00 + S02) shown in Equation (21) are obtained. The light intensity is obtained alternately. These results are obtained by combining with the modulation signal from the circular polarization modulator 45 in the lock-in amplifier 91 to determine which light intensity corresponds to which value, that is, 1/2 (S00-S02). Or ½ (S00 + S02). The recorder 92 distinguishes and stores the light intensity corresponding to 1/2 (S00-S02) and the light intensity corresponding to 1/2 (S00 + S02). From these results, the matrix element S02 of the Mueller matrix of the sample can be obtained.

  Next, the turntable 60 is rotated by 180 ° to obtain a configuration corresponding to the circular dichroism measuring device 3B shown in FIG. Then, the light corresponding to 1/2 (S00 + S20) shown in Equation (24) is obtained by operating the circular polarization modulator 45 to emit the right circularly polarized light and the left circularly polarized light alternately alternately. And the intensity of light corresponding to 1/2 (S00-S20) shown in Equation (26) are obtained alternately. These results are obtained by combining with the modulation signal from the circular polarization modulator 45 in the lock-in amplifier 91, which light intensity corresponds to which value, that is, whether 1/2 (S00 + S20). / 2 (S00-S20). In the recorder 92, the intensity of light corresponding to 1/2 (S00 + S20) and the intensity of light corresponding to 1/2 (S00-S20) are stored separately. From these results, the matrix element S02 of the Mueller matrix of the sample can be obtained.

  Finally, by adding the matrix elements S02 and S20 of the Mueller matrix obtained as a result of the above calculation, an accurate circular dichroism signal can be obtained as shown in Expression (28).

  As described above, according to the circular dichroism measurement device according to the fourth embodiment, as in the first embodiment, more accurate circular dichroism measurement from which artifact components are removed can be performed. Further, in comparison with the first embodiment, in the case of the circular dichroism device according to the fourth embodiment, the arrangement of the optical components and the sample is changed by rotating the turntable 60, so that the measurement can be performed more easily. it can. In addition, compared to the case where the arrangement is changed manually, the position and orientation of each part and sample can be accurately arranged along the optical axis, so circular dichroism can be measured more accurately. be able to. In addition, since the measurement can be performed without moving the sample 100, it is possible to perform measurement on a sample that is mechanically unstable, such as fragile or easy to fall. Furthermore, in the circular dichroism measuring device according to the fourth embodiment, signals of circular dichroism of various wavelengths can be obtained by simply changing the settings of the spectroscope and the circular polarization modulator without exchanging the monochromatic filter or the wave plate. Therefore, it is possible to easily obtain a circular dichroism spectrum.

(Fifth embodiment)
Next, the configuration of a circular dichroism measuring apparatus according to the fifth embodiment of the present invention will be described. In the following embodiments, the first to fourth embodiments are improved, and the configuration can measure the circular dichroism of the sample more accurately.

  FIG. 7 is a diagram showing a configuration of a circular dichroism measuring apparatus according to the fifth embodiment. In the circular dichroism measuring device 5 (third measuring device / S20 measuring means) shown in FIG. 7, the linearly polarized light source 15, the monochromatic filter 20, the 1 / 4λ wavelength plate 40, the polarizing plate 30, and the photodetector 50 are used as the light source 10. The sample 100 is arranged in this order along the optical axis from the first to the fourth, and the sample 100 is arranged on the optical path between the monochromatic filter 20 and the quarter-wave plate 40. Compared with the circular dichroism measuring apparatus according to the first embodiment, the most different point is that a linearly polarized light source 15 is used instead of the light source 10. Further, the arrangement of the sample 100, the quarter λ wavelength plate 40, and the polarizing plate 30 is also different from the circular dichroism measuring apparatus of the first embodiment.

  Hereinafter, a method for measuring the matrix element S20 shown in S02 and the mathematical expression (17) shown in the mathematical expression (16) using the circular dichroism measuring device 5 will be described. Here, for simplification of the following mathematical expressions, the Mueller matrices of the light source and the optical element are abbreviated as the following mathematical expressions (29) to (34).

  Here, when obtaining the matrix element S20 according to the equations (23) to (26) using the configuration according to the first embodiment shown in FIG. 1, the sample is irradiated with non-polarized light. The above formula does not hold unless the light is completely non-polarized light. That is, various matrix elements other than S20 are mixed.

  Since a light source actually used for measurement needs to transmit various optical elements such as a lens and a spectroscope, a slight polarization component is generated under the influence of these optical elements and optical arrangement. Therefore, in reality, it is extremely difficult to guarantee complete non-polarization. For this reason, in actual measurement, there has been a problem that a new artifact is generated due to a slight polarization component in the non-polarized light source.

  Therefore, the circular dichroism measuring apparatus 5 shown in FIG. 7 solves the above problem by using the linearly polarized light source 15 when measuring the matrix element S20. Specifically, in the circular dichroism measuring device 5 shown in FIG. 7, the linearly polarized light from the linearly polarized light source 15 is irradiated to the sample 100 through the monochromatic filter 20. The light transmitted through the sample 100 passes through the ¼λ wavelength plate 40 and the polarizing plate 30 and is converted into an electric signal by the photodetector 50. When the optical axis of light is defined as the Z-axis, the horizontal axis perpendicular to the Z-axis is defined as the Y-axis, and the vertical axis perpendicular to the Z-axis is defined as the X-axis. Installed at 45 ° to the X axis.

When the polarization axes of the linearly polarized light source 15 and the polarizing plate 30 are set so as to be in the X-axis direction, the Stokes matrix of the transmitted light from the sample can be obtained by matrix calculation represented by Expression (35).

In this case, the light intensity K00 detected by the photodetector 50 is the first term of Expression (35), that is, Expression (36).

Next, when the polarization axis of the linearly polarized light source 15 is rotated by 90 ° and set in the Y-axis direction, and the polarization axis of the polarizing plate 30 is maintained in the X-axis direction, the Stokes matrix of the transmitted light from the sample is expressed by the formula ( 37).

In this case, the light intensity K10 detected by the photodetector 50 is the first term of Expression (37), that is, Expression (38).

Next, when the polarization axis of the linearly polarized light source 15 is rotated by 90 ° and set in the X-axis direction, and the polarization axis of the polarizing plate 30 is also rotated by 90 ° and set in the Y-axis direction, the Stokes matrix of the transmitted light from the sample is , Is obtained by matrix calculation represented by Equation (39).

In this case, the light intensity K01 detected by the photodetector 50 is the first term of Equation (39), that is, Equation (40).

Next, when the polarization axis of the linearly polarized light source 15 is rotated by 90 ° and set in the Y-axis direction, and the polarization axis of the polarizing plate 30 is left in the Y-axis direction, the Stokes matrix of the transmitted light from the sample is expressed by the formula (40 ) To obtain the matrix calculation.

In this case, the light intensity K11 detected by the photodetector 50 is the first term of Equation (41), that is, Equation (42).

Using the four light intensities thus obtained, K00, K10, K01, and K11, the matrix element S20 can be obtained by performing the calculation shown in Equation (43).

  By adding the matrix element S20 obtained in this way and S02 obtained by the equation (22) according to the equation (28), artifact components other than the CD are canceled, and only a pure CD signal is obtained. Will be.

  According to the circular dichroism measuring apparatus of the fifth embodiment, since an artifact component can be canceled without using non-polarized light, a complete non-polarized light source is not necessary, and polarized light slightly contained in the non-polarized light source. Since new artifacts due to components do not occur, ideal artifact cancellation is possible.

(Sixth embodiment)
A circular dichroism measuring apparatus according to the sixth embodiment will be described with reference to FIG. FIG. 8A and FIG. 8B differ in the arrangement of each optical component and sample included in the circular dichroism measuring apparatus.

  In the circular dichroism measuring apparatus shown in FIG. 8, instead of the linearly polarized light source 15 used in the fifth embodiment, a general non-polarized light source 10 and the first polarizing plate 32 are combined to form a straight line. The point which makes the same function as the polarized light source 15 differs from the structure of 5th Embodiment. In addition, since only linearly polarized light is extracted by the first polarizing plate 32, the light source 10 does not have to be a completely non-polarized light source and may have a certain degree of polarization characteristics.

  First, in the circular dichroism measuring apparatus 6A of FIG. 8A, the light from the light source 10 is converted into linearly polarized light by the first polarizing plate 32 and then irradiated to the sample 100. The light transmitted through the sample 100 is detected by the photodetector 50 through the ¼λ wavelength plate 40 and the second polarizing plate 34.

In the above configuration, when the first polarizing plate 32 is set in the X-axis direction, the quarter-wave plate 40 is set at 45 degrees with respect to the X-axis, and the second polarizing plate 34 is set in the X-axis direction, Stokes of transmitted light is set. The matrix is obtained by matrix calculation represented by Expression (44).

In this case, the light intensity K00 detected by the photodetector 50 is the first term of Expression (44), that is, Expression (45).

Next, when the first polarizing plate 32 is set in the Y-axis direction, the 1 / 4λ wavelength plate 40 is set at 45 degrees with respect to the X-axis, and the second polarizing plate 34 is set in the X-axis direction, the Stokes matrix of the transmitted light is , Is obtained by matrix calculation represented by Equation (46).

In this case, the light intensity K00 detected by the photodetector 50 is the first term of Equation (46), that is, Equation (47).

Next, when the first polarizing plate 32 is set in the X-axis direction, the quarter-wave plate 40 is set at 45 degrees with respect to the X-axis, and the second polarizing plate 34 is set in the Y-axis direction, the Stokes matrix of the transmitted light is , Is obtained by matrix calculation represented by Equation (48).

In this case, the light intensity K01 detected by the photodetector 50 is the first term of Expression (48), that is, Expression (49).

Next, when the first polarizing plate 32 is set in the Y-axis direction, the 1 / 4λ wavelength plate 40 is set at 45 degrees with respect to the X-axis, and the second polarizing plate 34 is set in the Y-axis direction, the Stokes matrix of the transmitted light is , Is obtained by matrix calculation represented by Equation (50).

In this case, the light intensity K11 detected by the photodetector 50 is the first term of Expression (50), that is, Expression (51).

Using the four light intensities K00, K10, K01, and K11 obtained by the above measurement, the matrix element S20 is obtained by performing the calculation shown in the equation (52).

  As for the measurement of the matrix element S02, the measurement may be performed using the configuration of the circular dichroism measurement apparatus in the first embodiment shown in FIG. 1A, but instead, the measurement of FIG. By changing the arrangement of the optical components used in the circular dichroism measuring device 6A, as shown in FIG. 8B, the first polarizing plate 32, the second polarizing plate 34, and the 1 / 4λ wavelength plate 40 are used. It is also possible to measure S02 by arranging the optical arrangement so that light from the light source 10 is irradiated in the order of the sample 100 and rotating the first polarizing plate 32 and the second polarizing plate 34 together. . In the case of this configuration, since the optical elements from the light source 10 to the photodetector 50 are the same between the S02 measurement and the S20 measurement, the difference in transmittance due to the number of optical elements can be canceled, and the more accurate Measurement is possible.

  By adding the matrix elements S20 and S02 obtained in this way according to Equation (28), artifact components other than CD are canceled out, and only a pure CD signal is obtained.

  When the polarization direction is changed by rotating the polarizing plate as in this embodiment, if the light source 10 and the first polarizing plate 32 are rotated together along the Z-axis direction, the light source 10 Since the amount of light is the same regardless of the polarization characteristics, the matrix element S20 can be measured with higher accuracy. Similarly, if the second polarizing plate 34 and the photodetector 50 in the subsequent stage are rotated together, light can be detected with the same sensitivity regardless of the polarization characteristics of the photodetector 50, so that the accuracy is higher. The matrix element S20 can be measured.

  As described above, according to the circular dichroism measuring device according to the sixth embodiment, in addition to the effect obtained by using the circular dichroism device of the fifth embodiment, a special light source such as a non-polarized light source or a linearly polarized light source is used. Can be used as a light source 10, and a general light source whose polarization characteristics are not guaranteed can be used.

(Seventh embodiment)
Next, a circular dichroism measuring apparatus according to a seventh embodiment will be described with reference to FIG. The circular dichroism measuring device (fourth measuring device / S02 measuring means) according to the seventh embodiment is the same in optical components used as compared with the circular dichroism measuring device according to the sixth embodiment. The arrangement is different.

  In the circular dichroism measuring device 7 shown in FIG. 9, the light from the light source 10 is converted into linearly polarized light by the first polarizing plate 32, passes through the ¼λ wavelength plate 40, and is then irradiated on the sample 100. The Then, the light transmitted through the sample 100 is detected by the photodetector 50 through the second polarizing plate 34.

First, when the first polarizing plate 32 is set in the X-axis direction, the quarter-wave plate 40 is set at 45 degrees with respect to the X-axis, and the second polarizing plate 34 is set in the X-axis direction, the Stokes matrix of the transmitted light is It is obtained by matrix calculation represented by Equation (53).

In this case, the light intensity N00 detected by the photodetector 50 is the first term of the formula (53), that is, the formula (54).

Next, when the first polarizing plate 32 is set in the Y-axis direction, the 1 / 4λ wavelength plate 40 is set at 45 degrees with respect to the X-axis, and the second polarizing plate 34 is set in the X-axis direction, the Stokes matrix of the transmitted light is , And is obtained by matrix calculation represented by Equation (55).

In this case, the light intensity N10 detected by the light detector 50 is the first term of Expression (55), that is, (56).

Next, when the first polarizing plate 32 is set in the X-axis direction, the quarter-wave plate 40 is set at 45 degrees with respect to the X-axis, and the second polarizing plate 34 is set in the Y-axis direction, the Stokes matrix of the transmitted light is , Is obtained by matrix calculation represented by Equation (57).

In this case, the light intensity N01 detected by the photodetector 50 is the first term of Expression (57), that is, Expression (58).

Next, when the first polarizing plate 32 is set in the Y-axis direction, the 1 / 4λ wavelength plate 40 is set at 45 degrees with respect to the X-axis, and the second polarizing plate 34 is set in the Y-axis direction, the Stokes matrix of the transmitted light is , Is obtained by matrix calculation represented by Equation (59).

In this case, the light intensity N11 detected by the photodetector 50 is the first term of Equation (59), that is, Equation (60).

Using the four light intensities N00, N10, N01, and N11 obtained in this way, the matrix element S02 is obtained by performing the calculation shown in Equation (61).

  The matrix element S02 obtained in this way, and the matrix element S20 obtained according to the circular dichroism measuring apparatus 6A and the equations (44) to (52) according to the sixth embodiment shown in FIG. Are added according to the equation (28), artifact components other than CD are canceled out, and only a pure CD signal is obtained.

  According to the circular dichroism measuring apparatus according to the seventh embodiment, it is not necessary to change the arrangement of the first polarizing plate 32 and the second polarizing plate 34 when measuring the matrix elements S02 and S20. It becomes easy to introduce a stage.

(Eighth embodiment)
Next, a circular dichroism measuring apparatus according to the eighth embodiment will be described with reference to FIG. Compared with the circular dichroism measuring apparatus 8 according to the seventh embodiment, the circular dichroism measuring apparatus 8 according to the eighth embodiment shown in FIG. 10 has two 1 / 4λ wavelength plates (first 1/1 / 4λ wavelength plate 42 and second 1 / 4λ wavelength plate 44) are used.

  In FIG. 10, the light from the light source 10 is converted into linearly polarized light by the first polarizing plate 32, passes through the first ¼λ wavelength plate 42, and then irradiates the sample 100. The light transmitted through the sample 100 is detected by the photodetector 50 through the second quarter-wave plate 44 and the second polarizing plate 34.

  This embodiment is different from the fifth to seventh embodiments in that the same effect as that obtained by pulling out the wave plate is obtained by setting the angle of the wave plate at a polarization axis or perpendicular to the polarization axis. That is, in the case of the measurement of the matrix element S20, the first quarter-wave plate 42 of FIG. 10 is set to the same or right angle as the first polarizing plate 32 by setting the angle of the first quarter-wave plate 42 in FIG. The function as a wave plate is eliminated. Therefore, in that case, it can be considered that the optical arrangement is equivalent to the circular dichroism measuring apparatus 6A according to the sixth embodiment shown in FIG. Therefore, the matrix element S20 can be calculated according to the mathematical expressions (44) to (52) described in the sixth embodiment.

  In the case of the measurement of the matrix element S02, the second 1 / 4λ wavelength plate 44 is set to have the same angle as that of the second polarizing plate 34 or at an angle orthogonal to each other, whereby the second 1 / 4λ. Since the wave plate 44 does not function as a wave plate, it can be considered as an optical arrangement equivalent to the circular dichroism measuring device 7 described in the seventh embodiment. Therefore, the matrix element S02 can be measured using the mathematical expressions (53) to (61).

  By adding the matrix elements S02 and S20 obtained by the above method according to the equation (28), artifact components other than the CD are canceled, and only a pure CD signal is obtained.

  In other words, the set angles of the optical elements for this embodiment can be summarized in Table 1 below.

By using the eight values in Table 1 above and performing the calculation shown in the following formula (62), artifact components other than CD are canceled out, and only a pure CD signal is obtained.

  As described above, according to the circular dichroism measuring apparatus according to the eighth embodiment, it is not necessary to replace optical elements in the measurement of the matrix element S02 and the matrix element S20, so that a simpler and more accurate optical design can be achieved. It becomes possible.

(Ninth embodiment)
Next, a ninth embodiment of the present invention will be described. The arrangement of the optical components is the same as that of the circular dichroism measuring apparatus 8 according to the eighth embodiment, but is different from the eighth embodiment in that the sample can be rotated.

  Here, in addition to the four optical components shown in Table 1, the rotation angle of the sample is added, and the wavelength plate is not rotated (set to a common value) in the measurement of the light intensities N00 to N11 and the light intensities K00 to K11. Is as shown in Table 2.

  Further, in the measurement of K00 to K11 shown in Table 2, when the entire optical system is rotated by 45 degrees, the following Table 3 is obtained.

  Here, along the angle setting of Table 3, the first polarizing plate 32, the first ¼λ wavelength plate 42, the sample 100, the second ¼λ wavelength plate 44, and the second polarizing plate 34 By performing the calculation represented by the above equation (62) using N00 to N11 and K00 to K11 measured by adjusting the arrangement, artifact components other than CD are canceled out and only a pure CD signal is obtained. Will be.

  That is, according to Table 3, when measuring N00 to N11 and K00 to K11, respectively, it is necessary to rotate the first 1 / 4λ wavelength plate 42 and the second 1 / 4λ wavelength plate 44 when the sample is rotated. There is no. Therefore, according to the measurement method of the eighth embodiment, the first polarizing plate 32, the first 1 / 4λ wavelength plate 42, the second 1 / 4λ wavelength plate 44, and the second polarizing plate 34 are used. While it was necessary to rotate the optical component, in the measurement method of this embodiment, the first polarizing plate 32, the sample 100, and the second polarizing plate 34 require only two optical components and the sample. The number of stages can be reduced. Therefore, measurement can be performed more simply.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment,
Various changes can be made.

  For example, it is good also as a structure which combined the one part structure of the said 1st-4th embodiment suitably. In the first embodiment, the circular dichroism measuring devices 1A and 1B may be configured by changing the arrangement of optical components using the same device.

1, 2A, 2B, 3A, 3B, 4 ... circular dichroism measuring device, 10 ... light source, 20 ... monochromatic filter, 30 ... polarizing plate, 40 ... 1 / 4λ wavelength plate, 50 ... photodetector, 100 ... sample .

Claims (12)

S02 measurement step for measuring the matrix element S02 when the Mueller matrix related to the sample to be measured is represented by the following formula (1):
S20 measurement step of measuring the matrix element S20 in the following mathematical formula (1);
A calculation step of calculating circular dichroism from the matrix element S02 obtained in the S02 measurement step and the matrix element S20 obtained in the S20 measurement step;
A circular dichroism measuring method comprising:

The circular dichroism measuring method according to claim 1,
The S02 measuring step includes
A first light source that emits light of a specific wavelength, light that is emitted from the first light source is incident, and the first linearly polarized light that is linearly polarized light in the first direction is orthogonal to the first direction. A first polarizing plate capable of extracting second linearly polarized light that is linearly polarized light in the second direction, and the first linearly polarized light or the second linearly polarized light extracted from the first polarizing plate is incident on the first polarizing plate. When the wavelength of light from the first light source is λ, the first light is emitted with a phase difference between two polarization components having a vibration plane different from the vibration plane of incident light and orthogonal to each other as ¼λ. In a first measurement apparatus comprising: a wavelength plate; and first light detection means that detects transmitted light emitted from the first wavelength plate and transmitted by a sample by converting it into an electrical signal.
A first step of taking out the first linearly polarized light by the first polarizing plate and measuring the intensity of light transmitted through the sample;
A second step of taking out the second linearly polarized light by the first polarizing plate and measuring the intensity of light transmitted through the sample;
Have
The S20 measurement step includes
A second light source that emits light having the same wavelength as that of the first light source, and transmitted light that is emitted from the second light source and transmitted by the sample. A second wavelength plate that emits a phase difference between two polarization components orthogonal to each other having a vibration plane different from that of the second linearly polarized light, and light emitted from the second wavelength plate Is converted into an electric signal emitted from the second polarizing plate, a second polarizing plate capable of taking out the linearly polarized light in the first direction and the linearly polarized light in the second direction. A second measuring device comprising: a second light detecting means for detecting;
A third step of taking out the first linearly polarized light by the second polarizing plate and measuring the light transmitted through the sample;
A fourth step of taking out the second linearly polarized light by the second polarizing plate and measuring the light transmitted through the sample;
A circular dichroism measuring method characterized by comprising: The circular dichroism measuring method according to claim 1,
The S02 measuring step includes
A first light source that emits light of a specific wavelength, light that is emitted from the first light source is incident, and the first linearly polarized light that is linearly polarized light in the first direction is orthogonal to the first direction. A first polarizing plate capable of extracting second linearly polarized light that is linearly polarized light in the second direction, and the first linearly polarized light or the second linearly polarized light extracted from the first polarizing plate is incident on the first polarizing plate. When the wavelength of light from the first light source is λ, the first light is emitted with a phase difference between two polarization components having a vibration plane different from the vibration plane of incident light and orthogonal to each other as ¼λ. In a first measurement apparatus comprising: a wavelength plate; and first light detection means that detects transmitted light emitted from the first wavelength plate and transmitted by a sample by converting it into an electrical signal.
A first step of taking out the first linearly polarized light by the first polarizing plate and measuring the intensity of light transmitted through the sample;
A second step of taking out the second linearly polarized light by the first polarizing plate and measuring the intensity of light passing through the sample;
Have
The S20 measurement step includes
A third light source having the same wavelength as the first light source and capable of emitting linearly polarized light in the first direction and linearly polarized light in the second direction; and emitted from the third light source and transmitted by the sample Of the transmitted light, and the phase difference between two polarized light components having a vibration plane different from that of the first linearly polarized light or the second linearly polarized light and orthogonal to each other. A third wave plate that emits as 4λ, and a light beam that is emitted from the third wave plate is incident to extract linearly polarized light in the first direction and linearly polarized light in the second direction. In a third measuring apparatus comprising: three polarizing plates; and second light detecting means that converts and detects electric signals emitted from the third polarizing plate,
A third step of measuring light transmitted through the sample by emitting linearly polarized light in the first direction from the third light source, extracting linearly polarized light in the first direction from the third polarizing plate, and When,
A fourth step of measuring the light transmitted through the sample by emitting the linearly polarized light in the second direction from the third light source, extracting the linearly polarized light in the first direction from the third polarizing plate; When,
Fifth step of emitting linearly polarized light in the first direction from the third light source, taking out linearly polarized light in the second direction from the third polarizing plate, and measuring light transmitted through the sample When,
A sixth step of measuring the light transmitted through the sample by emitting the linearly polarized light in the second direction from the third light source, extracting the linearly polarized light in the second direction from the third polarizing plate, and When,
A circular dichroism measuring method characterized by comprising: Instead of the first measuring device,
A fourth light source having the same wavelength as the first light source and capable of emitting linearly polarized light in the first direction and linearly polarized light in the second direction; and linearly polarized light from the fourth light source is incident; A fourth wavelength plate that emits a phase difference between two polarization components orthogonal to each other and having a vibration plane different from the vibration plane of incident light, where λ is the wavelength of light from the fourth light source; A fourth polarizing plate capable of extracting linearly polarized light in the first direction and linearly polarized light in the second direction out of transmitted light emitted from the fourth wavelength plate and transmitted by the sample; and A fourth light detection means that converts the light emitted from the fourth polarizing plate into an electric signal and detects the electric signal;
The S02 measuring step includes
An eleventh step of measuring the light transmitted through the sample by emitting linearly polarized light in the first direction from the fourth light source and extracting linearly polarized light in the first direction from the fourth polarizing plate. When,
A twelfth step of emitting linearly polarized light in the second direction from the fourth light source, extracting linearly polarized light in the first direction from the fourth polarizing plate, and measuring light transmitted through the sample When,
Thirteenth step of emitting linearly polarized light in the first direction from the fourth light source, extracting linearly polarized light in the second direction from the fourth polarizing plate, and measuring light transmitted through the sample When,
A fourteenth step of emitting linearly polarized light in the second direction from the fourth light source, extracting linearly polarized light in the second direction from the fourth polarizing plate, and measuring light transmitted through the sample; When,
The circular dichroism measuring method according to claim 3, wherein: S02 measuring means for measuring the matrix element S02 when the Mueller matrix related to the sample to be measured is represented by the following mathematical formula (2):
S20 measuring means for measuring the matrix element S20 in the following mathematical formula (2);
Calculating means for calculating circular dichroism from the matrix element S02 obtained by the S02 measuring means and the matrix element S20 obtained by the S20 measuring means;
A circular dichroism measuring device comprising:

The circular dichroism measuring device according to claim 5,
The first measuring device constituting the S02 measuring means is:
A first light source that emits light of a specific wavelength;
The light emitted from the first light source is incident, the first linearly polarized light that is linearly polarized light in the first direction, and the second straight line that is linearly polarized light in the second direction orthogonal to the first direction. A first polarizing plate capable of extracting polarized light;
When the first linearly polarized light or the second linearly polarized light extracted from the first polarizing plate is incident and the wavelength of light from the first light source is λ, the vibration surface is different from the vibration surface of the incident light. A first wave plate that emits with a phase difference of 1 / 4λ between two polarization components orthogonal to each other,
First light detection means for detecting the light transmitted from the first wave plate and transmitted by the sample by converting it into an electrical signal;
With
The second measuring device constituting the S20 measuring means is
A second light source that emits light of the same wavelength as the first light source;
The transmitted light emitted from the second light source and transmitted by the sample is incident, and the transmitted light has a vibration surface different from the vibration surface of the first linearly polarized light or the second linearly polarized light and is orthogonal to each other. A second wave plate that emits with a phase difference of 1 / 4λ between the two polarization components to be
A second polarizing plate capable of receiving light emitted from the second wave plate and taking out linearly polarized light in the first direction and linearly polarized light in the second direction;
Second light detecting means for detecting by converting into an electric signal emitted from the second polarizing plate;
A circular dichroism measuring device comprising: The first measuring device includes:
A turntable on which the first polarizing plate, the first wave plate and the sample are placed;
When the turntable is rotated, the first polarizing plate, the first wavelength plate, and the sample are placed at a position that overlaps the optical path of the light from the first light source before the rotation,
The second measuring device is
The circular dichroism measuring device according to claim 6, wherein the circular dichroism measuring device is configured by rotating the turntable in the first measuring device. The first measuring device includes:
A turntable on which the first light source and the photodetector are placed;
In the turntable, a partition is provided between the first light source and the photodetector,
The optical path of light from the first light source and the optical path of light incident on the first light detection means are provided at positions that overlap each other when the turntable is rotated,
The second measuring device is
The circular dichroism measuring device according to claim 6, wherein the circular dichroism measuring device is configured by rotating the turntable in the first measuring device.   Instead of the first wave plate or the second wave plate, when the wavelength of the light from the first light source is λ, two polarization components having a vibration surface different from the vibration surface of the incident light and orthogonal to each other 9. The optical phase modulation means for periodically modulating the phase difference between the two and emitting the light after the phase difference modulation is used. Circular dichroism measuring device.   The said 1st light source or the said 2nd light source is comprised including the spectroscopy means which divides | segments and radiate | emits the light of a specific wavelength from the light of a several wavelength, The any one of Claims 6-9 characterized by the above-mentioned. The circular dichroism device according to item. The circular dichroism measuring device according to claim 5,
The first measuring device constituting the S02 measuring means is:
A first light source that emits light of a specific wavelength;
The light emitted from the first light source is incident, the first linearly polarized light that is linearly polarized light in the first direction, and the second straight line that is linearly polarized light in the second direction orthogonal to the first direction. A first polarizing plate capable of extracting polarized light;
When the first linearly polarized light or the second linearly polarized light extracted from the first polarizing plate is incident and the wavelength of light from the first light source is λ, the vibration surface is different from the vibration surface of the incident light. A first wave plate that emits with a phase difference of 1 / 4λ between two polarization components orthogonal to each other,
First light detection means for detecting the light transmitted from the first wave plate and transmitted by the sample by converting it into an electrical signal;
With
The third measuring device constituting the S20 measuring means is
A third light source having the same wavelength as the first light source and capable of emitting linearly polarized light in the first direction and linearly polarized light in the second direction;
The transmitted light emitted from the third light source and transmitted by the sample is incident, and the transmitted light has a vibration surface different from the vibration surface of the first linearly polarized light or the second linearly polarized light and is orthogonal to each other. A third wave plate that emits with a phase difference of 1 / 4λ between the two polarization components to be
A third polarizing plate capable of receiving light emitted from the third wavelength plate and taking out linearly polarized light in the first direction and linearly polarized light in the second direction;
Third light detection means for detecting by converting into an electric signal emitted from the third polarizing plate;
A circular dichroism measuring device comprising: Instead of the first measuring device,
A fourth light source having the same wavelength as the first light source and capable of emitting linearly polarized light in the first direction and linearly polarized light in the second direction; and linearly polarized light from the fourth light source is incident; A fourth wavelength plate that emits a phase difference between two polarization components orthogonal to each other and having a vibration plane different from the vibration plane of incident light, where λ is the wavelength of light from the fourth light source; A fourth polarizing plate capable of extracting linearly polarized light in the first direction and linearly polarized light in the second direction out of transmitted light emitted from the fourth wavelength plate and transmitted by the sample; and The circular dichroism measuring device according to claim 11, further comprising: a fourth measuring device including: a fourth light detecting unit configured to convert light emitted from the fourth polarizing plate into an electric signal and detect the electric signal.

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