CN100576046C - Light beam control method based on metal nano-seam - Google Patents

Abstract

Based on the light beam control method of metal nano-seam, according to the requirement of required function device (focusing, polarisation, disperse etc.) outgoing light field, the position phase distribution phi of computing element exit facet each point _i(x _i); As metal membrane material, determine incident wavelength skin depth in silverskin with argent; Minimum feature ω with the working ability correspondence _iAs the perforate of the metal at exit facet position phase maximal value place seam, as thickness of metal film d, be distributed as the basis mutually with outgoing light field position with the maximum machining depth of this live width correspondence with thickness of metal film d, calculate outgoing light field each point mode propagation constant β _i(x _i); Calculate the metal seam perforate size ω at other each point places of exit facet one by one _i(x _i) be starting point with phase maximal value place, position at last, skin depth is the metal kerf spacing, the seam that calculates adjacent seam is wide.The present invention can realize functions such as deviation, beam split, focusing, and can realize that the position distributes mutually arbitrarily at exit facet.

Description

Light beam control method based on metal nano-seam

Technical field

The present invention relates to a kind ofly modulate importing light wave, realize the light beam control method based on metal nano-seam of various electromagnetic waves (light wave) function element (deviation, focusing, beam split) by regulating metal micro-nano crack structure parameter (stitch wide).

Background technology

The metal micro structure of nanoscale has very unusual optical property, and this is confirmed by in recent years The experimental results.For these unusual optical phenomenas, people generally believe that the surface plasma excimer that light and metal micro structure effect are produced plays an important role therein, and the researchist of various countries has carried out Primary Study to the surface plasma excimer device that can break through diffraction limit.

The existing various document (L.Martin-moreno that delivered, Phys.Rev.Lett.90,167401 (2003), F.J Garcia-Vidal, Phys.Rev.Lett.90,213901 (2003)) relate to groove (shrinkage pool) the shape periodic structure of on metal film, making certain depth,, light is propagated in the far field with the certain energy and the very little angle of divergence by changing the quantity and the cycle of groove (shrinkage pool).But the problem that exists is: (1) emergent light is not concentrated in near-field energy, and the uncontinuity in the communication process has limited the application of this phenomenon in device; (2) still lack degree of freedom, make functions such as its deviation, beam split, focusing be difficult to realize as the angular modulation of important propagation characteristic.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, a kind of functions such as deviation, beam split, focusing of can realizing are provided, and can realize that at exit facet the position distributes mutually arbitrarily, the light beam control method based on metal nano-seam that capacity usage ratio is high.

Technical solution of the present invention is: based on the light beam control method of metal nano-seam, it is characterized in that finishing by following steps:

(1) according to the requirement of required function device (focusing, deviation, beam split etc.) outgoing light field, the position phase distribution phi of computing element exit facet each point _i(x _i);

(2) with argent as metal membrane material, determine incident wavelength skin depth in silverskin according to formula (1) $x_p=\frac{\mathrm{\λ}}{2\mathrm{\π}}{\left(\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_2}{{{\mathrm{\ϵ}}_1}^2}\right)}^{1/2}---\left(1\right)$

Wherein, ε ₁Be the real part of permittivity of argent, ε ₂Be the specific inductive capacity of medium, λ is a lambda1-wavelength;

(3) with the minimum feature ω of working ability correspondence _iAs the perforate of the metal at exit facet position phase maximal value place seam, as thickness of metal film d, be distributed as the basis mutually with outgoing light field position with the maximum machining depth of this live width correspondence with thickness of metal film d, calculate outgoing light field each point mode propagation constant β according to formula (2) _i(x _i)

${\mathrm{\β}}_i\left(x_i\right)=\frac{{\mathrm{\φ}}_i\left(x_i\right)}{d}---\left(2\right)$

(4), calculate the metal seam perforate size ω at other each point places of exit facet one by one according to formula (3) _i(x _i)

$\tanh (\sqrt{{\mathrm{\&beta;}}_i{\left(x_i\right)}^2-{\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="C2005100866990010H1.png"\; state="\{\{state\}\}">k</figure-callout>}}_0^2{e}_d{\mathrm{\&omega;}}_i\left(x_i\right)/2}$

$=\frac{-e_d\sqrt{{\mathrm{\&beta;}}_i{\left(x_i\right)}^2-{\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="C2005100866990010H1.png"\; state="\{\{state\}\}">k</figure-callout>}}_0^2{e}_m}}{e_m\sqrt{{\mathrm{\&beta;}}_i{\left(x_i\right)}^2-{\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="C2005100866990010H1.png"\; state="\{\{state\}\}">k</figure-callout>}}_0^2{e}_d}}---\left(3\right)$

β _i(x _i) be mode propagation constant, k ₀Be incident wave wave vector in a vacuum, ω _i(x _i) for diverse location metal seam wide, ε _mWith ε _dMaterial parameter for substrate and argent;

(5) be starting point with phase maximal value place, position, skin depth is the metal kerf spacing, and the point of getting the formula that satisfies condition (4) constitutes the consecutive point of micro-nano functional structure figure

$x_j=x_i+\frac{1}{2}{\mathrm{\&omega;}}_i+\frac{1}{2}{\mathrm{\&omega;}}_j+x_p---\left(4\right)$

x _iWith x _jBe respectively the position coordinates at the adjacent seam of microstructure center, x _pBe silver-colored skin depth, ω _iWith ω _jThe seam that is respectively adjacent seam is wide.

Principle of the present invention is: the surface plasma excimer transmission rule from independent metal seam, the transmission mode difference of surface plasma wave in the slit of discovery different in width, different transmission modes will cause electromagnetic wave propagation constant in the difference seam to produce difference, and the difference of propagation constant will cause the difference of metal seam position, exit phase, thereby the slit that can utilize different in width comes the position of slit outlet light wave is modulated mutually, can realize that with metallic diaphragm thickness (seam dark) position, exit portal place modulates mutually by the seam of regulating different slits is wide, and then realize modulation the outgoing light field.

The present invention compared with prior art has following advantage:

(1) position in each slit exit can be controlled separately mutually, thereby can realize that the position distributes mutually arbitrarily at exit facet;

(2) whole element is produced on the metallic film, is convenient to miniaturization and integrated;

(3) element produced of the inventive method has unusual transmission effect, capacity usage ratio height.

Description of drawings

Fig. 1 is embodiments of the invention 1 micro-nano function element section of structures, and wherein 1 is base material, and substrate can also can be metal for nonmetal, and 2 is the substrate surface metal level, and 3 is a series of airports that width does not wait;

Fig. 2 is embodiments of the invention 1 micro-nano function element structure vertical views, and wherein 2 is the substrate surface metal level, and 3 is a series of airports that width does not wait;

Fig. 3 be the embodiment of the invention 1 midplane ripple by metal construction shown in Figure 1 after, in the energy distribution of locating from exit facet 0.8 micron (focal plane), wherein horizontal ordinate is a position vector, 0.5 micron of every lattice, ordinate are that normalized energy distributes, every lattice are 0.1;

Fig. 4 is the embodiment of the invention 2 micro-nano function element section of structures, and wherein 1 is base material, and substrate can also can be metal for nonmetal, and 2 is the substrate surface metal level, and 3 is by airport;

Fig. 5 is the embodiment of the invention 2 micro-nano function element structure vertical views, and 2 is the substrate surface metal level, and 3 is a series of airports that width does not wait;

Fig. 6 be the embodiment of the invention 2 midplane ripples perpendicular to metal construction incident shown in Figure 4 after, the energy distribution that obtains at the exit facet rear, wherein 4 is incident light 650nm, 5 is micro-structured component, 6 are that the emergent light field energy distributes.

Embodiment

Embodiment 1 is long depth of focus, a submicron order focal spot spotlight effect of realizing plane wave by the inventive method, and its implementation process is as follows:

1. present embodiment need adopt micro-nano structure to realize long depth of focus, the submicron order focal spot focusing effect of plane light wave.According to the long depth of focus effect of element, at first calculate element light field exit facet position phase distribution phi by traditional diffraction theory _i(x _i), φ _i(x _i), for focusing structure,, then be x apart from the center if required focal length is f _iThe position at place is mutually:

${\mathrm{\&phi;}}_i\left(x_i\right)=2\mathrm{n\&pi;}+\frac{2\mathrm{\&pi;f}}{\mathrm{\&lambda;}}-\frac{2\mathrm{\&pi;}\sqrt{{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="C2005100866990009H2.png,C2005100866990010H1.png"\; state="\{\{state\}\}">f</figure-callout>}}^2+{x_i}^2}}{\mathrm{\&lambda;}}$

N is a positive integer in the formula, and λ is a lambda1-wavelength;

2. select Ag as metal material, the skin depth that can calculate silver according to formula (2) is 24nm;

3. can to process minimum feature be 50nm to equipment, the machinable depth capacity of this live width is 100nm, therefore gets wide 50nm, the metal crack structure parameter that the metal seam of dark 100nm is got along as dominant bit, and select the thickness of 100nm as argent, at quartz substrate surface evaporation 100 nanometer metallic silvers;

4. with wide 50nm, the corresponding position of the metal crack structure of dark 100nm is the dominant bit phase mutually, according to formula (2), (3), calculates the corresponding seam in other position wide (promptly obtaining position and the wide funtcional relationship of seam) respectively;

5. from the position-width function curve that calculates, select to satisfy the final structure parameter of the point of formula (4), and carry out processing and fabricating as device.

Fig. 1 is the sectional view of this focusing structure, and Fig. 2 is the vertical view of this focusing structure, and the energy distribution that Fig. 3 locates to obtain in design focus (0.8 micron) for this structure can find out that from above-mentioned each figure incident field locates to have obtained good focusing in focus (0.8 micron).

Embodiment 2 is the turnovers that realize the turnover light wave by the inventive method, and its implementation process is as follows:

1. present embodiment need adopt micro-nano structure to realize the deviation effect of plane light wave.At first, calculate element light field exit facet position phase distribution phi by traditional diffraction theory according to the long depth of focus effect of element _i(x _i);

2. select Ag as metal material, the skin depth that can calculate silver according to formula (2) is 24nm;

3. can to process minimum feature be 50nm to equipment, the machinable depth capacity of this live width is 100nm, therefore gets wide 50nm, the metal crack structure parameter that the metal seam of dark 100nm is got along as dominant bit, and select the thickness of 100nm as argent, at quartz substrate surface evaporation 100 nanometer metallic silvers;

4. with wide 50nm, the corresponding position of the metal crack structure of dark 100nm is the dominant bit phase mutually, according to formula (2), (3), calculates the corresponding seam in other position wide (promptly obtaining position and the wide funtcional relationship of seam) respectively;

5. from the position-seam width function curve that calculates, select to satisfy the final structure parameter of the point of formula (4), and carry out processing and fabricating as device.

Fig. 4 is the sectional view of this light field deviation structure, and Fig. 5 is the vertical view of this light field deviation structure, Fig. 6 for light field by the energy distribution after this structure, from the energy distribution of above-mentioned each figure as can be seen: incident field has obtained deviation.

In addition, the beam split function that realizes of the present invention is similar to the implementation process of above-mentioned focusing and deviation.

Claims (1)

1,, it is characterized in that finishing by following steps based on the light beam control method of metal nano-seam:

(1) according to the requirement of required function device outgoing light field, the position phase distribution phi of computing element exit facet each point _i(x _i):

${\mathrm{\&phi;}}_i\left(x_i\right)=2\mathrm{n\&pi;}+\frac{2\mathrm{\&pi;f}}{\mathrm{\&lambda;}}-\frac{2\mathrm{\&pi;}\sqrt{f^2+{x_i}^2}}{\mathrm{\&lambda;}}$

N is a positive integer in the formula, and λ is a lambda1-wavelength, and f is a focal length, x _iFor focusing structure apart from the center;

x _iWith x _jBe respectively the position coordinates at the adjacent seam of microstructure center;

(2) with argent as metal membrane material, determine incident wavelength skin depth in silverskin according to formula (1)

$x_p=\frac{\mathrm{\&lambda;}}{2\mathrm{\&pi;}}{\left(\frac{{\mathrm{\&epsiv;}}_1+{\mathrm{\&epsiv;}}_2}{{\mathrm{\&epsiv;}}_1^2}\right)}^{1/2}---\left(1\right)$

Wherein, ε ₁Be the real part of permittivity of argent, ε ₂Be the specific inductive capacity of metal slit filled media, λ is a lambda1-wavelength;

(3) with the minimum feature ω of working ability correspondence _iAs the perforate of the metal at exit facet position phase maximal value place seam, as thickness of metal film d, be distributed as the basis mutually with outgoing light field position with the maximum machining depth of this live width correspondence with thickness of metal film d, calculate outgoing light field each point mode propagation constant β according to formula (2) _i(x _i)

${\mathrm{\&beta;}}_i\left(x_i\right)=\frac{{\mathrm{\&phi;}}_i\left(x_i\right)}{d}---\left(2\right)$

(4), calculate the metal seam perforate size ω at other each point places of exit facet one by one according to formula (3) _i(x _i)

$\tanh (\sqrt{{\mathrm{\&beta;}}_i{\left(x_i\right)}^2-k_0^2{e}_d{\mathrm{\&omega;}}_i\left(x_i\right)/2}$

$=\frac{-e_d\sqrt{{\mathrm{\&beta;}}_i{\left(x_i\right)}^2-k_0^2{e}_m}}{e_m\sqrt{{\mathrm{\&beta;}}_i{\left(x_i\right)}^2-k_0^2{e}_d}}---\left(3\right)$

β _i(x _i) be mode propagation constant, k ₀Be incident wave wave vector in a vacuum, ω _i(x _i) for diverse location metal seam wide, ε _mWith ε _dMaterial parameter for substrate and argent;

(5) be starting point with phase maximal value place, position, skin depth is the metal kerf spacing, and the point of getting the formula that satisfies condition (4) constitutes the consecutive point of micro-nano functional structure figure

$x_j=x_i+\frac{1}{2}{\mathrm{\&omega;}}_i+\frac{1}{2}{\mathrm{\&omega;}}_j+x_p---\left(4\right)$

x _iWith x _jBe respectively the position coordinates at the adjacent seam of microstructure center, x _pBe silver-colored skin depth, ω _iWith ω _jThe seam that is respectively adjacent seam is wide.

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