CN103149616A - Reflective nanorod surface plasma optical filter - Google Patents

Abstract

The invention discloses a reflective nanorod surface plasma optical filter which comprises a substrate and nanorods, and the nanorods are evenly and symmetrically distributed on the surface of the substrate. The diameters of the nanorods are 300-500 nanometers, the heights of the nanorods are 200-500 nanometers, the inter-nanorod distances of the nanorods are 0-880 nanometers, and the distribution periods of the nanorods are the sum of the diameters of the nanorods and the inter-nanorod distances of the nanorods. The reflective nanorod surface plasma optical filter effectively solves the problem of polarization sensitivity of an optical filter device, has sensitive light reflecting and splitting effects, can promote the performance and reflection efficiency of the optical filter to the maximum, and is high in resolution ratio, stable and reliable in performance and structure, long in service life, wide in range of application and capable of accurately repeating various stored data.

Description

Reflection-type nano-pillar surface plasma light filter

Technical field

The present invention relates to light analysis and processing apparatus field, particularly a kind of reflection-type nano-pillar surface plasma light filter.

Background technology

Find first abnormal transport phenomena (the extraordinary optical transmission of light in metal sub-wavelength structure from the people such as French scientist Ebbesen in 1998, brief note is for EOT) since, the correlative study of relevant surface plasma has obtained concern and significant progress widely.Use the prepared device of surface plasma principle to have the advantages such as resolution is high, easy modulation, performance brilliance, and obtained in fields such as photoelectricity, new forms of energy (solar cell), data storage, micro-imagings widely and used.At present, already present surface plasma build light filter is the transmission-type light filter, namely can only realize the effect of light splitting under transmissive state.Mainly comprise two kinds of filtering methods: the first, the method that was proposed to use the white light source in the linear grooves grating pair broadband (broadband) of periodic structure to filter by Ebbesen seminar in 2008.The structure of the people such as Ebbesen design as shown in Figure 1, shining a silverskin width that is arranged in 300 nanometer thickness with a branch of white light source is the lower surface in the gap of 170 nanometers, etches respectively the different groove of the degree of depth in the both sides in upper surface one end this gap.The groove of both sides, nanometer gap can play the effect of antenna, collects the light signal that the nanometer gap is crossed in transmission, and the cycle size of the position of the transmission signal wave crest of coming and day line groove is closely related.Therefore, by using the sky line groove of different cycles, can accurately control the optical wavelength that the nanometer gap is crossed in transmission, and then reach the effect of light splitting.Second method is that utilization one-dimensional metal-insulator of being proposed in 2010 by L.Jay Guo seminar-metal (metal-insulator-metal, note by abridging be MIM) layer pile structure carries out light splitting to the white light source in broadband, as shown in Figure 2.The cycle layer heap optical grating construction of one dimension also has wavelength selectivity for white light source, and accurate control can be carried out by the cycle that modulating layer is piled grating in the position of crest.

No matter be notch antenna structure or the layer heap striated pattern structure of one dimension, all the polarization direction of incident light source had very strong selection requirement.Because the groove of one dimension and layer heap grating itself are all non-symmetrical structures, be parallel to groove or grating (transverse magnetic wave so only have when the incident light magnetic direction, transverse-magnetic wave, brief note is for TM) just have a spectrophotometric result, and can't realize spectrophotometric result for the transverse electric wave (transverse-electric wave, note by abridging be TE) that the incident light direction of an electric field is parallel to groove or grating.And in actual life, most of light source is all unpolarized natural light (as sunshine).Therefore, the polarization selectivity of linear structure has limited the scope of application of this type of filtering device greatly.In addition, can cause a part of luminous energy (be about gross energy half) to see through light filter due to polarization sensitivity but be reflected or absorb, make the efficiency of transmission of similar light filter very low, reduce the usability of instrument.

Summary of the invention

The technical matters that (one) will solve

The technical problem to be solved in the present invention is: how to provide a kind of reflection-type nano-pillar surface plasma light filter can solve the polarization sensitivity problem of filtering device, improve the reflection beam splitting effect and improve performance and the reflection efficiency of light filter, and Stability Analysis of Structures, range of application is wider.

(2) technical scheme

For solving the problems of the technologies described above, the invention provides a kind of reflection-type nano-pillar surface plasma light filter, described light filter comprises substrate and nano-pillar, described nano-pillar symmetrically be distributed in described substrate surface.

Preferably, the diameter of described nano-pillar is the 300-500 nanometer, and the height of described nano-pillar is the 200-500 nanometer, and the intercolumniation of described nano-pillar is the 0-880 nanometer, and the distribution cycle of described nano-pillar is nano-pillar diameter and nano-pillar intercolumniation sum.

Preferably, the material of described nano-pillar is: gold, silver or aluminium.

Preferably, the material of described substrate is quartz, silicon or gallium arsenide.

Preferably, the wavelength of resonance peak is:

${\mathrm{\&lambda;}}_{R\_\mathrm{mpq}}=\frac{a}{m}\{\sqrt{{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="HDA00002802235600042.png"\; state="\{\{state\}\}">p</figure-callout>}}^2+{\mathrm{<figure-callout\; id="2"\; label="q"\; filenames="HDA00002802235600042.png"\; state="\{\{state\}\}">q</figure-callout>}}^2}\&PlusMinus;\sin \left(\mathrm{\&theta;}\right)[p\cos \left(\mathrm{\&phi;}\right)+q\sin \left(\mathrm{\&phi;}\right)\left]\right\}$

Wherein a is the cycle of nano column array, and θ is that incident light is got to the incident angle on nano column array, and φ is the polarization angle of incident light, and m, p, q are nonnegative integer

Preferably, the wavelength of (θ=0) resonance peak is in the normal incidence situation:

${\mathrm{\&lambda;}}_{R\_\mathrm{mpq}}=\frac{a}{\mathrm{<figure-callout\; id="2"\; label="m\; p"\; filenames="HDA00002802235600042.png"\; state="\{\{state\}\}">m</figure-callout>}}\sqrt{p^{}}\sqrt{{}^2+{\mathrm{<figure-callout\; id="2"\; label="q"\; filenames="HDA00002802235600042.png"\; state="\{\{state\}\}">q</figure-callout>}}^2}$

(3) beneficial effect

Adopt reflection-type nano-pillar surface plasma light filter of the present invention effectively to solve the polarization sensitivity problem of filtering device, have sensitive reflection beam splitting effect and can amplitude peak improve performance and the reflection efficiency of light filter, and resolution is high, performance structure is reliable and stable, long service life, applied range, can the various data of preserving of accurate reproduction.

Description of drawings

Fig. 1 is the present invention's a kind of light filter of the prior art;

Fig. 2 is the present invention's a kind of light filter of the prior art;

Fig. 3 is the structural representation of embodiment of the present invention reflection-type nano-pillar surface plasma light filter;

Fig. 4 is the reflectance spectrum light splitting mechanism schematic diagram of embodiment of the present invention reflection-type nano-pillar surface plasma light filter;

Fig. 5 presents the linear relationship schematic diagram at embodiment of the present invention reflection-type nano-pillar surface plasma light filter resonant wavelength and array cycle;

Fig. 6 is the monochromatic corresponding relation figure of embodiment of the present invention reflection-type nano-pillar surface plasma light filter nano column array cycle and different colours;

Fig. 7 is the spectrophotometric result of embodiment of the present invention reflection-type nano-pillar surface plasma light filter nano column array under reflective-mode, and the corresponding reflectance spectrum of the monochromatic light of different colours;

Fig. 8 is the comparison diagram of the corresponding silver-colored post array that calculates of embodiment of the present invention reflection-type nano-pillar surface plasma light filter finite time-domain method of difference surface electric field intensity when resonance occurs and do not occur.

Embodiment

Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following examples are used for explanation the present invention, but are not used for limiting the scope of the invention.

The embodiment of the present invention provides a kind of reflection-type nano-pillar surface plasma light filter as shown in Figure 3, and described light filter comprises substrate and nano-pillar, described nano-pillar symmetrically be distributed in described substrate surface.The diameter of described nano-pillar is the 300-500 nanometer, and the height of described nano-pillar is the 200-500 nanometer, and the intercolumniation of described nano-pillar is the 0-880 nanometer, and the distribution cycle of described nano-pillar is nano-pillar diameter and nano-pillar intercolumniation sum.

Preferably, the material of described nano-pillar is: gold, silver or aluminium.

Preferably, the material of described substrate is quartz, silicon or gallium arsenide.

The embodiment of the present invention adopts the finite time-domain method of difference to carry out theoretic simulation and calculating take the nano-pillar structure as the basis, subsequently, the device of making is carried out performance test and analysis.Cylindrical light filter is operated under reflective condition, when a branch of white light source incides device surface from nano-pillar top, realizes light splitting at the homonymy of device, also can the signal that reflect be gathered and analyze simultaneously.The diameter of the nano-pillar that adopts in the embodiment of the present invention is 150 nanometer to 500 nanometers, can realize light splitting in the range of size below 1 micron.

Fig. 4 utilizes the principle of work of the reflectance spectrum of nano column array for the embodiment of the present invention light filter that uses finite time-domain method of difference theoretical modeling to calculate, its principle of work is: by the effect that realizes regulating local type surface plasma resonance with the nano column array of different cycles and finally be issued to filtering at reflective condition.Use similar nano-pillar structure, its range of adjustment not only can contain whole visible light wave range, can also cover the near infrared subregion.When changing the cycle of nano-pillar, the resonance peak in reflectance spectrum can be realized continuous accurate dynamic modulation, and the scope of modulation can realize red range and near-infrared band scope from 600 nanometers left and right to 1000 nanometers.

For reflection-type nano-pillar surface plasma light filter, because position and the array cycle at surface plasma body resonant vibration peak are closely bound up, the method in cycle that therefore can be by changing array is accurately controlled the position of resonance peak and is reached the effect of optical filtering.As shown in Figure 5, the growth of the cycle of the wavelength of resonance peak and nano column array meets linear relationship.For nano column array, the wavelength when resonance occurs can be used formula:

${\mathrm{\&lambda;}}_{R\_\mathrm{mpq}}=\frac{a}{m}\{\sqrt{{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="HDA00002802235600042.png"\; state="\{\{state\}\}">p</figure-callout>}}^2+{\mathrm{<figure-callout\; id="2"\; label="q"\; filenames="HDA00002802235600042.png"\; state="\{\{state\}\}">q</figure-callout>}}^2}\&PlusMinus;\sin \left(\mathrm{\&theta;}\right)[p\cos \left(\mathrm{\&phi;}\right)+q\sin \left(\mathrm{\&phi;}\right)\left]\right\}---\left(1\right)$

Represent, wherein a represents the cycle of nano column array, and θ is that incident light is got to the incident angle on nano column array, and φ is the polarization angle of incident light, and m, p, q are integer.For the situation of normal incidence (be θ=0 o'clock), formula (1) can be reduced to:

${\mathrm{\&lambda;}}_{R\_\mathrm{mpq}}=\frac{a}{\mathrm{<figure-callout\; id="2"\; label="m\; p"\; filenames="HDA00002802235600042.png"\; state="\{\{state\}\}">m</figure-callout>}}\sqrt{p^{}}\sqrt{{}^2+q^2}---\left(2\right)$

For the visible light wave range of being concerned about in this project, of paramount importance two resonant wavelengths are

${\mathrm{\&lambda;}}_{R\_m}^{\mathrm{air}}=\frac{a\&CenterDot;n_{\mathrm{air}}}{m}$ With ${\mathrm{\&lambda;}}_{R\_m}^{\mathrm{quartz}}=\frac{\mathrm{a\&CenterDot;}{n}_{\mathrm{quartz}}}{m}---\left(3\right)$

Be corresponding p=1, two kinds of situations of q=0 (or p=0, q=1) and p=q=1, the refractive index evaluation just mates with the refractive index size of air and the quartz substrate that adopts, thereby has reached resonance mode.

In order further to realize filter effect at whole visible light wave range, cycle of nano column array further is reduced to below 400 nanometers, thereby realizes the white light source of a branch of broadband (broadband) is divided into the monochromatic light of different colours.When the structural parameters in use Fig. 6, the monochromatic light of different colours just can clearly be separated from a branch of broadband white light source.In Fig. 6, the cycle of listed nano column array all measures by the scanning electron microscope diagram that uses high-amplification-factor.When life cycle is respectively the array of 540,485,430,375,320 nanometers, make red, yellow, and green, green grass or young crops, blue these five kinds of basic colors be separated from the white light source in broadband.As shown in Figure 7, Fig. 7 has showed the spectrophotometric result of nano column array under reflective-mode that experiment records, and the corresponding reflectance spectrum of the monochromatic light of different colours.

Different from the resonance state of single nano-pillar, for nano column array, when resonance occurs, more energy is in the gap that is gathered between nano-pillar.This is because in the cavity between these nano-pillar, energy more easily is limited and preserves, by effective control of pair array parameter, can effectively reduce the evaporation loss of the basad direction of energy and top direction of air, make in the resonant cavity of most of concentration of energy between nano-pillar.As shown in Figure 8, for the array that spacing is 50 and 20 nanometers, near-field field strength all can have when not occuring significantly compared to resonance when resonance occurs increases, and the nano-pillar spacing is less, and the enhancing of energy is more obvious.But no matter spacing is big or small, energy is all in the cavity that mainly concentrates between nano-pillar.It can also be seen that from Fig. 8, when (left column) field intensity maximal value occurs than resonance when resonance occurs, (right row) can effectively not increase respectively approximately 50 times and 300 times.In addition, no matter can find out from vertical view (row) or sectional view (lower row), the energy of light can well be limited in zone between nano-pillar, that is to say that the loss of prepared light filter is very little, has relatively high reflection efficiency.

Above embodiment only is used for explanation the present invention; and be not limitation of the present invention; the those of ordinary skill in relevant technologies field; without departing from the spirit and scope of the present invention; can also make a variety of changes and modification; therefore all technical schemes that are equal to also belong to category of the present invention, and scope of patent protection of the present invention should be defined by the claims.

Claims (6)

1. a reflection-type nano-pillar surface plasma light filter, is characterized in that, described light filter comprises substrate and nano-pillar, described nano-pillar symmetrically be distributed in described substrate surface.

2. reflection-type nano-pillar surface plasma light filter claimed in claim 1, it is characterized in that, the diameter of described nano-pillar is the 300-500 nanometer, the height of described nano-pillar is the 200-500 nanometer, the intercolumniation of described nano-pillar is the 0-880 nanometer, and the distribution cycle of described nano-pillar is nano-pillar diameter and nano-pillar intercolumniation sum.

3. reflection-type nano-pillar surface plasma light filter claimed in claim 2, is characterized in that, the material of described nano-pillar is: gold, silver or aluminium.

4. reflection-type nano-pillar surface plasma light filter claimed in claim 2, is characterized in that, the material of described substrate is quartz, silicon or gallium arsenide.

5. reflection-type nano-pillar surface plasma light filter claimed in claim 2, is characterized in that, the wavelength that the crest of surface plasma body resonant vibration occurs is:

Wherein a is the cycle of nano column array, and θ is that incident light is got to the incident angle on nano column array, and φ is the polarization angle of incident light, and m, p, q are nonnegative integer

6. reflection-type nano-pillar surface plasma light filter claimed in claim 5, is characterized in that, the wavelength of (θ=0) resonance peak is in the normal incidence situation:

${\mathrm{\&lambda;}}_{R\_\mathrm{mpq}}=\frac{a}{m}\sqrt{p^2{+q}^2}$

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