JP4292295B2 - Electromagnetic field characteristic evaluation system - Google Patents

Description

  The present invention relates to an electromagnetic field characteristic evaluation system for evaluating an electric conductor by a time domain difference method (FDTD method), and more specifically, electric conduction of a metal or the like in a material structure to be analyzed. Even if a material with negative characteristics or a material with a negative dielectric constant is included, the calculation process of the time domain difference method is executed stably and accurately without obtaining divergence, and the evaluation data of the analysis target is obtained The present invention relates to an electromagnetic field characteristic evaluation system.

  In recent years, coupled with higher performance of laser diodes, research and development aimed at an advanced information society has been actively promoted, and application of optical technology not only in the information processing field but also in various fields is progressing. On the other hand, due to the remarkable development of computers in recent years, the penetration of computational science represented by computer simulation is also progressing in the field of optical technology development and research. Above all, the time domain difference method is indispensable as an important development research tool because it can easily evaluate the behavior of electromagnetic waves in the material structure, and the time domain difference method aims at the application of light and electromagnetic waves. In recent technological development, it has been frequently used as an easy means for analyzing the behavior of electromagnetic waves in a material structure.

  In the time domain difference method, if the material to be analyzed is composed only of a dielectric material that does not conduct electricity, it can be calculated without any problem. However, if an electrically conductive material such as metal is included, the calculated value is unchanged. It diverges to infinity and cannot perform calculation processing. A simple solution to this is a method that assumes a perfect conductor, and puts the electric field inside the perfect conductor at zero. With this method, detailed analysis and evaluation of materials due to differences in metal types cannot be performed.

  The divergence prevention method used by many commercial softwares up to now is a method of reducing the electric conductivity to zero. That is, in solving Maxwell's equation, the first coefficient of the electric field term for calculating the electric field is set to “1”. In fact, the effect of setting the coefficient to “1” is small. The electrical conductivity of the second coefficient is taken into account depending on the case. However, as occurs in many metal material evaluation processes, when the imaginary part of the complex refractive index is larger than the real part, the real part of the complex dielectric constant is negative and the second coefficient is negative. If the calculated value diverges. In this case, there is no theoretical basis, but a method of solving the problem by taking the absolute value of the dielectric constant with importance on effectiveness is adopted.

As a method for overcoming these difficulties, an RC method (recursive convolution method) has been proposed. This RC method is a technique for introducing dispersion of dielectric constant. So far, for example, a method of introducing a Lorentz-type linear dispersion model (Non-Patent Document 1) has been proposed and widely used.
“J. Opt. Soc. Am. A” Vol. 12, No. 9, p. 1974 (1995)

  However, the RC method can be said to be a method in which the expansion formula is considerably complicated, the replacement with a forcible constant and the constant value are fixed, and the objection remains in the theoretical validity. In recent years, research and development utilizing the optical properties of metal fine particles and metal thin films has become active in fields such as near-field light application technology, micro optical element technology, high-density information recording technology, and nanotechnology fields. There is a problem that in the program using, it is impossible to analyze and calculate the material structure including these, or even if it is possible, the validity remains.

  The present invention has been made under such circumstances, and the object of the present invention is to reduce the negative dielectric constant when an electrically conductive material such as a metal is included in the material structure to be analyzed. To provide an electromagnetic field characteristic evaluation system that can perform stable evaluation without performing divergence even if the indicated materials are included and can be evaluated without including logical contradictions throughout the entire evaluation system. It is in.

  Another object of the present invention is that the evaluation of electrical conductors can be made up of only those parameters that can be obtained experimentally, even if there is no experimental data. It is an object of the present invention to provide an electromagnetic field characteristic evaluation system that can be calculated from calculations using constants established in the above and is expected to obtain highly accurate evaluation.

  As a result of extensive research, the present inventors have not been bound by the form of the expansion formula when solving Maxwell's equation using the time domain difference method, but the physical meaning of the coefficient of the first term of the formula. Rethinking it, expressing it as it is, and substituting that expression into the coefficient of the second term, it can be summarized into a clean expression, it can be found that various problems can be solved at once. The invention has been completed.

  That is, the electromagnetic field characteristic evaluation system according to the present invention includes an arithmetic processing module that calculates an electric field component, a magnetic field component, an influencing component that the magnetic field change has on the electric field, an influencing component that the electric field change has on the magnetic field, and the boundary condition, and the arithmetic processing module. A parameter setting processing module for setting electric field and magnetic field parameters for arithmetic processing, and a control processing module for controlling the arithmetic processing module and the parameter setting processing module to execute arithmetic processing, in a time domain An electromagnetic field characteristic evaluation system that performs an arithmetic processing to solve Maxwell's equation using a finite difference method and evaluates an electromagnetic field characteristic in an evaluation target material, wherein the parameter setting processing module sets a parameter for the arithmetic processing module Time domain difference method in processing When solving Maxwell's equations, the two coefficients in the formula representing the effect of the change in the magnetic field on the electric field are replaced by a formula representing relaxation instead of a coefficient derived by a normal method. To do.

  According to the electromagnetic field characteristic evaluation system of the present invention having the above-described characteristics, the material parameters necessary for the calculation are the relaxation coefficient or lifetime of the excitation electric field, electrical conductivity, complex dielectric constant or complex Refractive index. Both values are measurable by experiment, but the relaxation coefficient or lifetime that is relatively difficult to experiment can be estimated with high accuracy from the coefficient of electric conductivity and the theoretically determined coefficient. And the complex dielectric constant or the complex refractive index. The relaxation coefficient is the reciprocal of the lifetime, the complex dielectric constant can be derived from the complex refractive index, and the complex refractive index can be derived from the complex dielectric constant.

  In the electromagnetic field characteristic evaluation system of the present invention, by using the above formula, a stable solution can be obtained without the calculated value diverging infinitely, and the required input data is minimal and these Data can be obtained experimentally, and an evaluation system that can expect high calculation accuracy by using data that is close to reality is provided.

  As part of research on high-density information recording and reproducing methods using near-field light, it is necessary to develop a computer program that can analyze these electromagnetic fields in research involving metal fine particles. In the programming using various formula expansions and methods that have been known in the past, the above-described problems have been encountered in any of the methods, but the problem can be solved by using the electromagnetic field characteristic evaluation system according to the present invention. The electromagnetic field characteristic evaluation system according to the present invention is a case where an electrically conductive material such as a metal is included in the material structure to be analyzed by examining the characteristic evaluation in various programming and verification through individual cases. Even if a material exhibiting a negative dielectric constant is included, it can be verified that stable evaluation can be performed without divergence, and it can be confirmed that the evaluation is performed without including logical contradiction throughout the entire evaluation system.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 17 is a diagram illustrating the hardware configuration of the electromagnetic field characteristic evaluation system according to the present invention, and FIG. 18 is a block diagram showing the configuration of the arithmetic processing module of the main part of the electromagnetic field characteristic evaluation system according to the present invention.

  The hardware configuration of the electromagnetic field characteristic evaluation system will be described with reference to FIG. As a hardware configuration of the electromagnetic field characteristic evaluation system, an ordinary computer device is used. The entire hardware configuration of the electromagnetic field characteristic evaluation system includes an information input unit, an information recording unit, a calculation unit, and an information display unit. The entire operation is controlled by a program, and an analysis calculation of electromagnetic field characteristic evaluation is processed by a program. Specifically, the specific hardware configuration includes a central processing unit (CPU) 101, a system memory (ROM) 102, a work memory (RAM) 103, and an HDD (hard disk drive) that provides a storage area used as a data memory. 104 and HD (hard disk) 105, FDD (flexible disk drive) 106 and FD (flexible disk) 107 for providing an external storage area, display 108, I / F (interface) 109, keyboard 110, and mouse 111 A scanner 112, a printer 113, and the like, which are connected by a bus 100, respectively.

  The CPU 101 performs overall control and data processing of calculation processing. The ROM 102 stores a program such as a boot program. The RAM 103 is used as a work area for the CPU 101. The HDD 104 controls reading / writing of data with respect to the HD 105 according to the control of the CPU 101. The HD 105 stores data written under the control of the HDD 104.

  The FDD 106 controls reading / writing of data with respect to the FD 107 according to the control of the CPU 101. The FD 107 stores data written under the control of the FDD 106 or reads data stored in the FD 107. In addition to the FD 107, the removable recording medium may be a CD-ROM (CD-R, CD-RW), MO, DVD (Digital Versatile Disk), memory card, or the like. The display 108 displays data such as a document, an image, and function information as well as a cursor, an icon, or a tool box. As the display 108, for example, a CRT, a TFT liquid crystal display, a plasma display, or the like is used.

  The I / F 109 is connected to a network such as the Internet through a communication line, and is connected to other devices via this network. The I / F 109 controls a network and an internal interface, and controls data input / output from an external device. For example, a modem or a LAN adapter is used as the I / F 109.

  The keyboard 110 includes keys for inputting characters, numbers, various instructions, and the like, and inputs data. Moreover, a touch panel type input pad or a numeric keypad may be used. The mouse 111 performs cursor movement, range selection, window movement, size change, and the like. A trackball or a joystick may be used as long as they have the same function as a pointing device.

  The scanner 112 optically reads an image. The printer 113 prints image data and document data. For example, a laser printer or an ink jet printer is used as the printer 113.

  FIG. 18 is a block diagram showing a configuration of a main part of the arithmetic processing module in the electromagnetic field characteristic evaluation system according to the present invention, and the arithmetic processing here is shown by a data flow. A rectangular block indicates a parameter setting processing module for setting each parameter for data processing for performing electromagnetic field characteristic evaluation. An elliptical block indicates a calculation process for electromagnetic field characteristic evaluation according to the set parameters. An arithmetic processing module to be performed is shown. Although not shown, an arithmetic processing module for calculating the electric field component, an arithmetic processing module for calculating the magnetic field component, a control processing module for controlling the arithmetic processing module and the parameter setting processing module to execute the arithmetic processing are provided. .

  The outline of the processing will be explained here. In this case, the arithmetic processing for solving Maxwell's equations using the time domain difference method is performed. In this case, the control processing module controls the arithmetic processing to calculate the magnetic field component and the electric field component. Repeat the calculation while updating the time. For the calculation of the electric field component, first, the parameter setting processing module performs the parameter setting process of the electric field and the magnetic field based on the initial setting, performs the first time update (calculation blocks 201 and 202), and based on the set parameter, Calculate the electric field component. Here, the electric field component is calculated by the arithmetic processing module. In that case, the relaxation calculation is performed on the calculated calculation result, and then the calculation process of the boundary condition of the electric field boundary is performed (calculation blocks 203 to 203). 206). Thereby, parameters for calculating the magnetic field components are obtained, and parameters for calculating the electric field and the magnetic field at the next time are obtained.

  In accordance with the obtained calculation result, the electric field parameter is set, the magnetic field component is calculated, and the boundary condition of the magnetic field boundary is calculated for the calculated calculation result (calculation blocks 207 to 210). ). As a result, the parameters for calculating the electric field and magnetic field at the next time are obtained, so the parameter setting of the magnetic field is performed, the boundary non-reflection condition is processed, and the electric field and magnetic field at the next time are calculated. The time update process is performed (calculation blocks 211 to 213), and the process from the calculation block 202 is repeated to calculate the electric field and magnetic field at the next time.

  Next, a description will be given, with reference to the drawings, of main programs and formula development for calculation for constituting each arithmetic processing module in the electromagnetic field characteristic evaluation system of the present invention. In order to facilitate understanding here, a case where a program constituting the arithmetic processing module is coded as a FORTRAN program will be described as an example. FIG. 1 shows a formula expansion procedure for obtaining a basic formula used in an electromagnetic field characteristic evaluation system according to the present invention by applying the time domain difference method to a pure Maxwell equation in the absence of a current source or a magnetic current source. .

と置く。この関係を第２項の係数に当てはめると、

と書ける。結局式は次式となる。

When solving Maxwell's equations using the time domain difference method, an equation that replaces the two coefficients in the equation representing the effect of the change in the magnetic field on the electric field with an equation representing relaxation instead of the coefficient derived by the normal method is Use. Since the first term on the right side of the finally obtained expression represents attenuation relaxation, this coefficient is replaced with the expression for attenuation relaxation. That is,

Put it. If this relationship is applied to the coefficient of the second term,

Can be written. After all, the formula becomes the following formula.

で両係数を近似表現すると、次式が得られる。

特に、第２項の近似表現は、実際の計算において、元の式に比して計算結果が安定する。ただし、電気伝導度σが０の物質の場合、第１項は係数を“１”とし、第２項は元の表記を用いて、次式を用いる。

ここでの第２項のベクトル演算は、次の数式で表される計算である。

Since ΓΔt is usually much smaller than 1, the following expression obtained by Taylor expansion of the exp (−ΓΔt) portion

If both coefficients are approximated by, the following equation is obtained.

In particular, the approximate expression of the second term is more stable in the actual calculation than in the original expression. However, in the case of a substance having an electrical conductivity σ of 0, the first term uses a coefficient “1”, and the second term uses the original notation and uses the following equation.

The vector operation of the second term here is a calculation represented by the following mathematical formula.

  An electric field and a magnetic field are arranged in one unit cell as shown in FIG. Depending on how the cells are set, there is a difference in how to obtain the average value described below, but the portions related to the present invention are handled in the same manner.

となる。 For each field component, when written down in detail, for example E _x is

It becomes.

Here, since the E _x is on a unit cell of four boundary lines, by using the average value of gamma, the coefficient of the first term is as follows.

となる。 Similarly, the coefficients of the second term and the third term are expressed by the average of the coefficients of the four unit cells, and after calculating the individual coefficients, the average is obtained.

It becomes.

Similar equations are obtained for E _y and E _z . In addition, the magnetic field component is the same as the previous method. For example, for _{H x,} as follows.

Since H _x is on the boundary surface of the two unit cells, the coefficient is calculated using the average of the magnetic susceptibility μ of the two related cells.

などは、プログラム中では全てセル（ｉ，ｊ，ｋ）に関する成分として、配列（ｉ，ｊ，ｋ）に格納する。 Similar expressions are obtained for H _y and H _z . Appear in the expression here

Are all stored in the array (i, j, k) as components relating to the cell (i, j, k) in the program.

  An example in which the formula expansion described so far is programmed by FORTRAN is shown in FIGS. In addition to the examples shown here, various irregular forms can be considered as the average of the coefficients, but this is a part not related to the essence of the present invention, and may be selected as appropriate.

  In the electromagnetic field characteristic evaluation system according to the time domain difference method of the present invention, the material structure to be analyzed diverges even when an electrically conductive material such as a metal is included or a material having a negative dielectric constant is included. Therefore, the characteristic evaluation can be obtained by a method that can be calculated stably without causing any logical contradiction in expression expansion.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

[Example 1]
As a basic example, an example in which a two-dimensional electromagnetic field characteristic evaluation in the vicinity of the surface of a metal fine particle is performed will be described. Evaluation is made on a case where fine particles of a metal of 30 nanometers (aluminum, gold, silver, copper, etc.) are in the air and a transverse wave (TE wave) is incident thereon.

において、ｒｓは自由電子の半径、ａ₀はBohr半径で、ｒ_s／ａ₀はほとんどの場合“２”ないし“３”の値をとり、多くの教科書に載っている。例えば、Al=2.07，Au=3.01，Ag=3.02，Cu=2.67である。σは電気伝導度でΩ^-1ｍ^-1の単位で表された数値を用いる。 First, the method for obtaining the relaxation coefficient Γ among the coefficients necessary for the calculation will be examined. Formula obtained from theoretical calculation using the Drude model for the electronic state of the metal,

In, rs is the free electron radius, a ₀ in the Bohr radius, to r _s / a ₀ is the case most of the "2" does not take a value of "3", rests on a number of textbooks. For example, Al = 2.07, Au = 3.01, Ag = 3.02, Cu = 2.67. σ is a numerical value expressed in units of Ω ⁻¹ m ^{−1 in} terms of electrical conductivity.

The experimental value of electrical conductivity is obtained from the data book. For example, the values at 25 ° C. are Al = 3527.6, Au = 4402.7, Ag = 5890.2, and Cu = 5592.8. In either case, the unit is Ω ⁻¹ m− ¹ .

からの値、Al=0.159323E+15、Au=0.415347E+14、Ag=0.262161E+14、Cu=0.571739E+14と比較すると、かなり良い一致が見られる。緩和係数を実験的に求めるには、フェムト秒の超短パルスレーザーなどの設備が必要であるが、とりあえずは、計算値で代用可能と考えられる。 Substituting these values to obtain the relaxation coefficient Γ, Al = 0.14528E + 15, Au = 0.37858E + 14, Ag = 0.28017E + 14, and Cu = 0.42698E + 14 were obtained. The unit is (sec ⁻¹ ). In order to investigate the credibility of this value, the following equation regarding the relaxation coefficient Γ described in Non-Patent Document 1 is used.

Compared with the values from the following: Al = 0.159323E + 15, Au = 0.415347E + 14, Ag = 0.262161E + 14, Cu = 0.571739E + 14, there is a fairly good agreement. In order to obtain the relaxation coefficient experimentally, equipment such as a femtosecond ultrashort pulse laser is required, but for the time being, it is considered that the calculated value can be substituted.

  The calculation result in the case of silver is shown in FIG. The refractive index of silver was defined as the real part (0.13) and the imaginary part (5.3). In FIG. 6, the magnitude of the electromagnetic wave for one period is averaged and expressed in height. When a transverse plane wave having a wavelength of 780 nm travels from the back toward the front, an enhancement due to surface plasmons is observed in the vicinity of the metal surface. It can be applied to analysis of surface enhanced Raman scattering (SERS) using surface of metal fine particles and surface plasmon excitation fluorescence.

  As described above, in addition to the above-described height, the method of expressing the magnitude of the electromagnetic wave can be expressed by contour lines, coloring, or the like. Select and use according to the purpose. Also, instead of averaging the magnitude of the electromagnetic wave for one period, it can also be displayed as a moving animation by sequentially displaying the change every moment.

[Example 2]
The inventors of the present invention have been researching and developing an ultra-high density information recording optical disk using near-field light called a super-lens (super-resolution near-field structure). An example of the electromagnetic field characteristic evaluation for the initial simplified model of Super-RENS will be described.

  FIG. 7 is a model configuration diagram of a TA-type Super-RENS in which a metal antimony is used for the functional layer and a transmission-type opening is formed in the light irradiation central portion, and FIG. 8 is a light irradiation central portion using silver oxide as the functional layer. It is a model block diagram of the LSC type Super-RENS which produces | generates a silver fine particle and makes it a light-scattering nucleus.

  Assuming a case where light having a wavelength of 635 nm is illuminated with a lens having a numerical aperture of 0.6, which is narrowed down to the diffraction limit, and an electromagnetic field characteristic change when the information recording mark portion is scanned by rotating the optical disk was evaluated.

  FIG. 9 and FIG. 10 show the results of evaluating the electromagnetic field characteristics when these two types of disks are rotationally scanned. These figures are actually moving images with motion animations. With the evaluation system according to the present invention, it is possible to accurately estimate the influence of metal antimony fine apertures and silver fine particles on light waves. In addition, it can be seen from this result that a larger signal can be obtained with the LSC type Super-RENS than with the TA type Super-RENS.

[Example 3]
Titanium dioxide, known as a photocatalyst, is a substance that exhibits a catalytic effect when exposed to ultraviolet light, and is usually white powder particles. As an application that focuses on bactericidal and deodorizing effects, it is often used in familiar products. It is also used to decompose and detoxify various environmental pollutants. A more excellent photocatalyst can be obtained by supporting a platinum promoter on the surface of titanium dioxide particles.

  FIG. 11 shows an example of evaluating the electromagnetic field characteristics when platinum ultrafine particles are brought into contact with the surface of titanium dioxide fine particles. This is a case where platinum ultrafine particles having a diameter of 30 nm are attached to the right lateral surface and the upper surface of the titanium particles. In addition to the electrochemical catalytic enhancement effect known as the Honda-Fujishima effect, it is expected that the electromagnetic field characteristics due to surface plasmon enhancement on the metal surface may be involved. The enhancement effect by itself was greater.

[Example 4]
Electromagnetic field analysis at the probe end of a probe used in a near-field scanning optical microscope (NSOM) is important for designing a probe shape and analyzing an obtained image.

  Similar to the super lens described in the second embodiment, the probes are roughly classified into an aperture type and a scattering type, and there are many cases involving metals such as a metal-coated aperture type probe and a scattering type probe using a metal tip. In either case, the surface plasmon effect in which the electromagnetic field on the metal surface is locally enhanced is effectively used.

  FIG. 12 shows an example of an electromagnetic field characteristic evaluation result of an aperture type probe coated with metal. This is an example of a case where an aperture type probe whose glass tip is coated with silver, an aperture of 100 nm diameter, and a glass beam is irradiated with a Gaussian light beam. FIG. 13 shows an example of an electromagnetic field characteristic evaluation result of a scattering probe using a metal tip. This is a case where the needle-shaped silver tip is irradiated with a Gaussian light beam from the side.

[Example 5]
Electromagnetic field characteristics of metal thin films also occupy a large position as a near-field light application field. Here, an example of the most classic and frequently used Kretschmann arrangement will be described.

  The Kretschmann arrangement is an optical arrangement shown in FIG. 14, and the light totally reflected on the prism surface excites the plasmon on the surface of the metal thin film, and the excited plasmon light is used to detect and identify the compound attached to the surface. And is known for its very high sensitivity.

  To detect the adhesion of a compound, a slight change in refractive index due to adhesion is detected from a change in incident angle (resonance angle) that optimally excites plasmon light. For identification of the attached compound, for example, fluorescence emission using plasmon light is used.

  FIG. 15 shows an example of generation of plasmon light excited by the Kretschmann arrangement. As shown in the figure, when 10 nm thick silver is applied to the glass surface and irradiated with a Gaussian beam from an oblique angle of 44 degrees, the resonance condition is not completely satisfied, but there is a sign of surface plasmon excitation. It is done.

[Example 6]
When a metal periodic structure, more specifically, a metal diffraction grating is irradiated with light having an incident angle that satisfies a resonance condition, surface plasmon light is excited on the diffraction grating.

  Similar to the use of plasmon light described in Example 5, for example, it can be used for highly sensitive detection and identification of a compound attached to the surface. FIG. 16 shows an example of an electromagnetic field characteristic evaluation result obtained by analyzing the generation state of surface plasmon light excited on a metal diffraction grating. As shown in the figure, when the surface of a silver diffraction grating with a grating interval of 1 micron is irradiated with a Gaussian beam from an oblique angle of 44 degrees. Although the resonance condition is not satisfied, there is a sign of surface plasmon excitation.

したがって、請求項２に記載した式の代わりに次式となる。

[Example 7]
When there is a current source J, Maxwell's equation is:

Therefore, instead of the formula described in claim 2, the following formula is obtained.

と置く。この関係を第２項、第３項の係数に当てはめると、

と書ける。結局式は次式となる。

Apply the present invention and replace with the attenuation relaxation equation. That is,

Put it. If this relationship is applied to the coefficients of the second and third terms,

Can be written. After all, the formula becomes the following formula.

As described above, the replacement of the present invention can be applied to the third term, and the evaluation analysis can be stably performed with a slight program modification.

It is the figure which showed the formula expansion | deployment procedure until the basic formula used for description of this invention is obtained by applying the time-domain difference method to Maxwell's equation when there is no current source or magnetic current source. It is a figure of a three-dimensional FDTD unit cell. It is an example of a part of the initial setting part of the parameter of the FORTRAN program in the three-dimensional FDTD. It is a figure which shows the example of a part of electric field calculation part of the FORTRAN program in 3D FDTD. It is a figure which shows the example of a part of magnetic field calculation part of the FORTRAN program in three-dimensional FDTD. It is a figure which shows an example of the calculation result by two-dimensional FDTD which showed electromagnetic wave intensity distribution by height distribution when a transverse wave plane wave injects into the silver fine particle put in the air. It is a figure which shows the model structure of TA type | mold Super-RENS which uses a metal antimony for a functional layer, and forms a transmissive | pervious opening in the light irradiation center part. It is a figure which shows the model structure of LSC type Super-RENS which uses silver oxide for a functional layer, produces | generates silver fine particle in the light irradiation center part, and makes it a light-scattering nucleus. It is a figure which shows an example of the electromagnetic field characteristic evaluation result at the time of rotationally scanning a TA type Super-RENS disc. It is a figure which shows an example of the electromagnetic field characteristic evaluation result at the time of carrying out rotation scanning of the LSC type Super-RENS disc. It is a figure which shows an example of an electromagnetic field characteristic evaluation at the time of making platinum ultrafine particles contact the titanium dioxide particle surface. It is a figure which shows an example of the electromagnetic field characteristic evaluation result of the metal-coated opening type probe. It is a figure which shows an example of the electromagnetic field characteristic evaluation result example of the scattering type probe using a metal front-end | tip. It is a figure which shows the optical arrangement | positioning of Kretschmann. It is a figure of the example of generation | occurrence | production of the plasmon light excited by Kretschmann arrangement | positioning. It is a figure of the example of an electromagnetic field characteristic evaluation result which analyzed the generation | occurrence | production state of the surface plasmon light excited on the metal diffraction grating. It is a figure explaining the hardware constitutions of the electromagnetic field characteristic evaluation system by this invention. It is a block diagram which shows the structure of the arithmetic processing module of the principal part of the electromagnetic field characteristic evaluation system by this invention.

Claims (9)

An electric field component, a magnetic field component, an influence component that the magnetic field change has on the electric field, an arithmetic processing module that calculates the influence component that the electric field change has on the magnetic field, and boundary conditions An operation for solving Maxwell's equations using a time-domain difference method, comprising: a parameter setting processing module for setting the parameters of the control unit; and a control processing module for controlling the arithmetic processing module and the parameter setting processing module to execute the arithmetic processing. It is an electromagnetic field characteristic evaluation system that performs processing and evaluates the electromagnetic field characteristics of the material to be evaluated.
The parameter setting processing module, in the process of setting parameters for the arithmetic processing module,
When solving Maxwell's equations using the time domain difference method, an equation that replaces the two coefficients in the equation representing the effect of the change in the magnetic field on the electric field with an equation representing relaxation instead of the coefficient derived by the normal method is An electromagnetic field characteristic evaluation system to be used,
The two coefficients derived by the normal method are respectively expressed by the following equations:

And
The formula representing the relaxation is

Where Γ is a relaxation coefficient and is an equation representing the rate of attenuation relaxation after Δt time. In the electromagnetic field characteristic evaluation system according to claim 1,
The expression that expresses the effect of magnetic field changes on the electric field is

E ⁿ is the electric field at time n, E ⁿ⁻¹ is the electric field at time n−1, H ^{n− (1/2)} is the magnetic field at time n− (1/2), σ is the electrical conductivity, ε Is an electromagnetic field characteristic evaluation system characterized by a dielectric constant. In the electromagnetic field characteristic evaluation system according to claim 1,
The following equation expresses the effect of magnetic field changes on the electric field:

Electromagnetic field characteristic evaluation system characterized by using In the electromagnetic field characteristic evaluation system according to claim 3,
ΓΔt is obtained by Taylor expansion of the exp (−ΓΔt) part.

The formula which replaced both coefficients or only one is also included.
An electromagnetic field characteristic evaluation system characterized by that. In the electromagnetic field characteristic evaluation system according to claim 4,
What replaces both coefficients is

An electromagnetic field characteristic evaluation system characterized by In the electromagnetic field characteristic evaluation system according to claim 3 or claim 5,
When the electrical conductivity σ is 0, the electromagnetic field characteristic evaluation system is characterized in that the coefficient of the second term of the formula is Δt / ε. In the electromagnetic field characteristic evaluation system according to claim 1,
The evaluation of the electromagnetic field characteristics of the evaluation target material is performed by inputting parameters of the dielectric constant, magnetic permittivity, electrical conductivity, and attenuation relaxation coefficient as substance parameters of the evaluation target material, inputting substance arrangement information, and An electromagnetic field characteristic evaluation system characterized by evaluating an electromagnetic field characteristic. In the electromagnetic field characteristic evaluation system according to claim 7,
The dielectric constant and electrical conductivity are calculated from the real part and imaginary part of the complex refractive index, the attenuation relaxation coefficient is calculated from the electrical conductivity or complex dielectric constant, and the dielectric constant and the magnetic inductivity are input as material parameters. An electromagnetic field characteristic evaluation system characterized by evaluating the electromagnetic field characteristic of a material. The electromagnetic field characteristic evaluation system according to claim 8,
Electrical conductivity and the attenuation relaxation factor inputs the experimental value, the electromagnetic field characteristics evaluation system, characterized in that to obtain the evaluation of the data.

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