CN104034271A - Interference rotation mapping detection method with transverse resolution of 1nm - Google Patents

Abstract

The invention discloses an interference rotation mapping detection method with transverse resolution of 1nm. The method is characterized in that a double-arm interference microscope system is designed. The system can present a reference reflecting surface and the image of an object to be detected at a unified position so as to avoid interference. Spectrum or stripes formed by interference can reflect the optical path difference of a point to be detected. A rotating/scanning platform under piezoelectric driving is mounted under the object to be detected, and transverse scanning with accuracy of 1nm and 360-degree rotating can be achieved. Through a differential collection method, an optical length projection with ultrahigh resolution in the one-dimensional direction can be obtained. Therefore, a three-dimensional image with ultrahigh resolution can be reconstructed by rotating the sample and collecting the optical length projections of the sample at multiple angles.

Description

A kind of lateral resolution reaches the interference rotation map detection method of 1nm

Technical field

The present invention relates to the micro-detection technique of ultrahigh resolution, refer to that especially one, based on Michelson interferometer structure, has the detection technique of rotation map ultrahigh resolution imaging.

Background technology

Micro-imaging technique has a wide range of applications in fields such as electronics technology, biomedicine, chemical materials.Along with scientific and technical development, people are also more and more higher to the requirement of microscopic resolution.But traditional optical microphotograph resolution can be subject to the restriction of diffraction limit, be merely able to realize the resolution of submicron order, cannot meet the application needs of development in science and technology.

In order to solve the problem of optical microscope diffraction limit, scientific research personnel has developed a series of ultrahigh resolution microscopic system.Electron microscope is the ultrahigh resolution microscope being most widely used at present, and it adopts electron beam to substitute light beam, to imaging of samples.Because the wavelength of electron beam is much smaller than visible light wavelength, thereby can realize higher resolution.But the electron beam that electron microscope uses has serious injury to cell, and environment must be near vacuum state, so can not observe living cells, this has seriously limited the application of electron microscope at biomedical sector.

Scanning probe microscopy is another ultrahigh resolution microscope.Scanning probe microscopy utilizes the imaging resolution of the displacement resolution alternative optical system of piezoelectricity translation stage, realizes high-resolution electric scanning imaging.The scanning probe microscopy polytypes such as atomic force microscope, scanning electron microscope that developed, but be not suitable for the detection to dynamic sample the sweep time that this class microscope need to be very long.

Also there is the relevant technical method of breaking through diffraction limit optical microscope aspect.As late 1920s proposes, the Near-field Optical Microscope being just achieved in the eighties in 20th century, adopt nano optical fibers probe, gather diffraction light signal by being controlled at wavelength dimension close contact scope, realized the super-resolution optical scanning imaging of 30nm left and right.And for example " random optics is rebuild microscopy ", " the photoactivation location microtechnic " etc. of the development beginning of this century, these class methods are used the principle of local tomography, the one part of pixel in specific activation graph picture only in Polaroid, to prevent crosstalking between pixel, can realize the super-resolution scanning imagery of 20-30nm.But these class methods are in order to realize lighting of pixel in batches, sample must use fluorescence processing, and fluorescence labeling can produce certain toxicity to biological sample, and makes whole testing process greatly complicated.Above method all needs to obtain piece image the detection time of growing very much, is not suitable for the detection of dynamic sample.

In addition, also have the instruments such as ellipsometer test, white light interferometer can be in the ultrahigh resolution that longitudinally realizes nanometer level.This quasi-instrument utilizes the interference of light self or polarization to realize the resolution of nanometer level, but its range of dynamic measurement only has hundreds of nanometer, and this resolution only can embody the variation of sample surfaces thickness, and higher lateral resolution cannot be provided.

Summary of the invention

The object of the present invention is to provide a kind of lateral resolution to reach the interference rotation map detection method of 1nm, it is characterized in that at one the sample surfaces thickness including dynamic sample is interfered to realize according to the following steps in mapping detection system:

Step (1), construct an optical interference structure, by rotation sample, the longitudinal frame mapping of interfering thickness measure is resolved to lateral resolution, for realizing the interference rotation map detection system of three-dimensional ultrahigh resolution imaging, comprising: light source (1), collimating mirror (2), beam splitter (3), the first object lens (41), the second object lens (42), computing machine (5), imaging len (6), sensitive detection parts (7), electronic rotation/translation three-dimensional motion objective table (8), and catoptron (9), wherein:

Light source (1) is laser or other white light source,

Beam splitter (3) is any in level crossing, dichroic mirror or prism,

The first object lens (41), are positioned at length-adjustable gage beam arm end,

The second object lens (42), are positioned at length-adjustable reference arm arm end,

Sensitive detection parts (7), are spectrometer while adopting white light to make light source, while adopting laser to make light source, are CCD device, and the output terminal of described sensitive detection parts (7) is connected with described computing machine (5),

Electronic rotation/translation three-dimensional motion objective table (8), be called for short objective table (8), be positioned under described the first object lens (41), be attached with the microcarrier chip of sample for mounting surface, described objective table (8) is three layers of nested structure, skin is motor actuation movement platform, centre is piezoelectric crystal actuation movement platform, internal layer is rotation sweep platform, microcarrier chip is fixed on internal layer rotation sweep platform, described objective table (8) is under the control of described computing machine (5), complete scanning and rotation to sample on described microcarrier chip, to obtain the full spectral information of each point that sample is had living space,

It is upper that the light that light source (1) sends impinges perpendicularly on described beam splitter (3) after described collimating mirror (2) is collimated into directional light, is divided into transmitted light and reflected light; Described transmitted light converges on described microcarrier chip through described the first object lens (41), after being reflected back, pass through again described the first object lens (41), be collimated into directional light, send to described beam splitter (3), be reflected to after described imaging len (6) is gone up and pool object light; Described reflected light is collimated into after directional light through described the second object lens (42), reflected by described catoptron (9), and then be collimated into directional light through described the second object lens (42), after described beam splitter (3) transmission, pool reference light by described imaging len (6) again; Described object light and reference light coherence stack are received by described sensitive detection parts (7), then send to described computing machine (5), form and interfere high-resolution spectroscopy, are called for short high spectrum;

Step (2), described a kind of lateral resolution reaches the interference rotation map detection method of 1nm, and implementation step is as follows:

Step (2,1), adjusts gage beam and becomes identical optical path length with reference arm, and object light and reference light are interfered;

Step (2,2), described computing machine (5) is controlled described objective table (8), is adjusted to horizontal level, opens described light source (1), obtains the high spectrum of sample;

Step (2,3),, under described computing machine (5) is controlled, described objective table (8) is around horizontal rotational shaft, find out the anglec of rotation α of reflective light intensity maximum point, obtain the high spectrum of interference of sample under described anglec of rotation α;

Step (2,4), the high spectrum of described interference that step (2,3) is obtained, carries out microcarrier chip high spectrum intervention thickness coding/decoding numerical solution, calculates the radial thickness information ρ of sample under anglec of rotation α;

Step (2,5), calculate according to the following formula mapping along slope coordinate y and the lateral coordinates x of sample under anglec of rotation α:

x＝ρ×Cosα，

y＝ρ×Sinα；

Step (2,6), by radial thickness resolution ax ρ, calculates mapping longitudinal frame Δ y and the lateral resolution Δ x of sample under anglec of rotation α according to the following formula:

Δx＝Δρ×Cosα，

Δy＝Δρ×Sinα。

A kind of lateral resolution provided by the invention reaches the interference rotation map detection method of 1nm, it is characterized in that described microcarrier chip high spectrum intervention thickness coding/decoding method, by numerical solution calculated thickness, measure radially or longitudinal thickness resolution can reach 1nm; Be further characterized in that described interference high-resolution spectroscopy is applicable to interference spectrum or the interference fringe of any interference structure device generation of all two part or all of coherence stack in corrugated.

No matter use the one dimension distribution plan of which kind of method acquisition thickness of sample, all can obtain by rotatable stage the thickness one dimension distribution plan of multiple angle shots.These thickness one dimension distribution plans are integrated, utilize Radon transform method can realize two dimensional surface imaging and fault information, utilize multi-angle to interfere high spectrum reconstruct to restore 3 d surface topography information, utilize spectrum coding method that longitudinal frame is mapped to lateral resolution, the resolution of two dimension, three-dimensional reconstruction figure is consistent with the resolution of one dimension distribution plan, has the feature of 1nm ultrahigh resolution.

A kind of lateral resolution provided by the invention reaches the interference rotation map detection method of 1nm, it is characterized in that described sample is any in biomolecule, abiotic molecule, cell, tissue, virus, microorganism, bacterium, micro-processing structure and nano material.

Brief description of the drawings

Fig. 1 broadband light super-resolution microscope equipment structural representation

Fig. 2 laser super-resolution microscope equipment structural representation

The poor mapping relations figure with interference fringe of Fig. 3 image planes

The mapping relations figure of Fig. 4 phase differential score value and optical path difference variable quantity

Fig. 5 angle coverage, angular resolution and last relation of rebuilding between image

Fig. 6 interferes rotation map to realize the extremum principle of longitudinal frame to lateral resolution conversion

Fig. 7 interferes the example of rotation map method reduction triangle shape nanostructured

Fig. 8 interferes rotation map to realize the General Principle of longitudinal frame to lateral resolution conversion

Embodiment

1, system and device structure

Now illustrate the embodiment of the method by measuring the experiment of aluminium-foil paper surface pattern.The invention provides one high spectrum microscopic system as depicted in figs. 1 and 2, comprising light source 1, collimating mirror 2, beam splitter 3, reference arm object lens 42, gage beam object lens 41, imaging lens 6, sensitive detection parts 7, rotation/translation objective table 8, catoptron 9 and computing machine 5.Rotation/translation objective table 8 uses piezoelectric crystal to drive and realizes the translation of nm resolution, and universal stage uses turbine and worm transmission.When light source is selected white light, sensitive detection parts 7 need to be used spectrometer 7a, and when light source is selected laser, sensitive detection parts 7 need to be used CCD7b.The length of reference arm or gage beam can regulate.

Specific to all parts, the wideband light source of system can adopt broadband halogen tungsten lamp, electric power 250W, luminous flux 9000 lumens, spectral range 400nm – 2500nm.Light coupling fiber, is transmitted to collimation lens top, and emergent light is input in system after being collimated by collimation lens.LASER Light Source adopts semiconductor laser, wavelength 650nm (or other wavelength), and luminous power 50mW is input in system after collimation lens is transformed into directional light.

System is used flat field infinity camera lens, numerical aperture 0.60, operating distance 3.7-2.7mm; Eyepiece focal length 800nm.Camera lens enlargement factor 61.5 ×.Object lens are fixed on electric elevating rack, so that electromotive focusing.

System rotation/translation objective table 8 comprises translation stage and universal stage two parts, and the translation stage that wherein used is double-layer nested structure, and outer for motor drives platform, internal layer is piezoelectric drive platform.It is 6 μ m that motor drives the step resolution of platform, and the step resolution of piezoelectric drive platform is 2nm, with closed loop servo control.Universal stage is fixed on piezoelectric drive platform.

2, light path detection method

System is used wideband light source or LASER Light Source illumination.While adopting different light sources, different light path detection methods need to be used, the variation of measured object surface thickness could be accurately detected.

In the time using wideband light source, reference image can interfere with measurement picture in spectral domain, need to use spectrometer as sampler.The spectral response range of spectrometer requires, for 0.2-1.1 μ m or wider, can cover UV-visible-infrared wave band comprehensively.When reference image and measure optical path difference between picture hour, the frequency of interference spectrum is lower; In the time that the optical path difference between reference image and measurement picture is larger, the frequency of interference spectrum is higher.Trickle optical path difference changes the variation that can be presented as phase place.As shown in Figure 1, phase place changes with the variation of optical path difference substantially linear, so can obtain by difference integrating method the one dimension distribution plan of thickness of sample.

In the time using LASER Light Source, reference image produces interference fringe with measuring picture meeting, need to use CCD as receiving device.CCD collects as shown in Figure 2, the light and shade striped being caused by image planes alternate position spike.In the time of the thickness of sample attenuation on gage beam or thickening, the light path of corresponding point position can shorten or be elongated, and the variation of this light path finally can cause interfering inside or outside convergent-divergent.The every variation one-period of annulus, correspondence shows that optical path difference has changed a wavelength.Interference circle and standard annulus are subtracted each other, can obtain isocontour difference.Difference and change in optical path length linear dependence.Can infer the average change in optical path length that current measurement point according to the variation of striped.Can obtain equally the one dimension distribution plan of thickness of sample by difference integrating method.In like manner, in the time that objective table tilts, between measurement face and reference surface, can form a fixing angle.If two planes are all strictly smooth, in the time that objective table moves, interference fringe also should uniform motion.And in the time of the out-of-flatness of measurement face, the athletic meeting of interference fringe forms velocity variations, by detecting this velocity variations, can obtain equally the one dimension distribution plan of thickness of sample.

When use, first be adjusted to equal length with reference to arm and gage beam, make reference image (as corrugated in Fig. 3 11) and measure picture (as corrugated in Fig. 3 12) can superpose (as corrugated in Fig. 3 13) successfully interfere, form interference spectrum or interference fringe (as circular interference fringe 14 in Fig. 3).Use spectrometer or CCD to collect interference spectrum or interference fringe.The pass of interference spectrum and optical path difference is:

$\begin{array}{c}{\left|R\left(\mathrm{\λ}\right)\right|}^2={\left|\mathrm{Rs}\left(\mathrm{\λ}\right)\right|}^2+{\left|\mathrm{Rr}\left(\mathrm{\λ}\right)\right|}^2-2\·\left|\mathrm{Rs}\left(\mathrm{\λ}\right)\right|\·\left|\mathrm{Rr}\left(\mathrm{\λ}\right)\right|\·\cos \left(\frac{2\mathrm{\π\Δ}}{\mathrm{\λ}}\right)\\ ={\left|\mathrm{Rs}\left(\mathrm{\λ}\right)\right|}^2+{\left|\mathrm{Rr}\left(\mathrm{\λ}\right)\right|}^2-2\·\left|\mathrm{Rs}\left(\mathrm{\λ}\right)\right|\·\left|\mathrm{Rr}\left(\mathrm{\λ}\right)\right|\·\cos \left(\frac{4\mathrm{\πnd}}{\mathrm{\λ}}\right)\end{array}---\left(1\right)$

If reference point thickness is d ₀, measurement point amounts of thickness variation is d _Δ, measurement point one-tenth-value thickness 1/10 is d ₀+ d _Δ.In the time of thickness thickening, spectrum can drift about to red end.Spectrum before variation is as shown in curve in Fig. 4 21, and the spectrum after changing is as shown in curve in Fig. 4 22.In the time that thickness changes, the optical path difference before changing and after changing is:

$\begin{array}{c}{\left|R\left(\mathrm{\λ}\right)\right|}^2{|}_{{d=d}_0}-{\left|R\left(\mathrm{\λ}\right)\right|}^2{|}_{d=d_0+d_{\mathrm{\Δ}}}\\ =-2\·\left|\mathrm{Rs}\left(\mathrm{\λ}\right)\right|\·\left|\mathrm{Rr}\left(\mathrm{\λ}\right)\right|\·\{\cos \left(\frac{{4\mathrm{\πnd}}_0}{\mathrm{\λ}}\right)-\cos [\frac{4\mathrm{\πn}(d_0+d_{\mathrm{\Δ}})}{\mathrm{\λ}}\left]\right\}\\ =-4\·\left|\mathrm{Rs}\left(k\right)\right|\·\left|\mathrm{Rr}\left(k\right)\right|\·\sin (\frac{{4\mathrm{\πnd}}_0}{\mathrm{\λ}}+\frac{{4\mathrm{\πnd}}_{\mathrm{\Δ}}}{2\mathrm{\λ}})\·\sin \left(\frac{{4\mathrm{\πnd}}_{\mathrm{\Δ}}}{2\mathrm{\λ}}\right)\end{array}---\left(2\right)$

To λ integration, cancellation λ-variable:

${\∫}_{{\mathrm{\λ}}_{\min }}^{{\mathrm{\λ}}_{\max }}|-4\·|\mathrm{Rs}\left(k\right)|\·|\mathrm{Rr}\left(k\right)|\·\sin (\frac{{4\mathrm{\πnd}}_0}{\mathrm{\λ}}+\frac{{4\mathrm{\πnd}}_{\mathrm{\Δ}}}{2\mathrm{\λ}})\·\sin \left(\frac{{4\mathrm{\πnd}}_{\mathrm{\Δ}}}{2\mathrm{\λ}}\right)|\·\mathrm{d\λ}---\left(3\right)$

Formula (3) can be split as three products:

${\∫}_{{\mathrm{\λ}}_{\min }}^{{\mathrm{\λ}}_{\max }}|-4\·|\mathrm{Rs}\left(k\right)|\·|\mathrm{Rr}\left(k\right)\left|\right|\·\mathrm{d\λ}---\left(4\right)$

${\∫}_{{\mathrm{\λ}}_{\min }}^{{\mathrm{\λ}}_{\max }}\left|\sin (\frac{{4\mathrm{\πnd}}_0}{\mathrm{\λ}}+\frac{{4\mathrm{\πnd}}_{\mathrm{\Δ}}}{2\mathrm{\λ}})\right|\·\mathrm{d\λ}---\left(5\right)$

${\∫}_{{\mathrm{\λ}}_{\min }}^{{\mathrm{\λ}}_{\max }}\left|\sin \left(\frac{{4\mathrm{\πnd}}_{\mathrm{\Δ}}}{2\mathrm{\λ}}\right)\right|\·\mathrm{d\λ}---\left(6\right)$

Formula (4), containing Δ, can not be regarded a constant as.In formula (5), d _Δcompare d ₀very little, thus negligible, thus this also can regard a constant as, by the long-pending constant C that is designated as of these two constants, that is:

$C={\∫}_{{\mathrm{\λ}}_{\min }}^{{\mathrm{\λ}}_{\max }}|-4\·|\mathrm{Rs}\left(k\right)|\·|\mathrm{Rr}\left(k\right)|\·\sin \left(\frac{{4\mathrm{\πnd}}_0}{\mathrm{\λ}}\right)|\·\mathrm{d\λ}---\left(7\right)$

Formula (6) is about d _Δa function, count M (d _Δ), by itself and formula (7) substitution formula in the lump (3), abbreviation is CM (d _Δ).Due to M (d _Δ) analytic solution too complicated, therefore can ask its numerical solution, result as shown in curve in Fig. 4 23, the reflectance spectrum in left figure before 21 corresponding variation in thickness, the reflectance spectrum after 22 corresponding variation in thickness.From the right figure curve 23 of Fig. 4, amounts of thickness variation becomes the relation of approximately linear within the scope of 50nm with measured value, and the resolution of thickness measure can reach 1nm.The one-dimensional scanning that coordinates piezotable, the method can obtain the light path information at each point place on one dimension straight line.Due to the existence of diffraction phenomena, between the pixel in the method and pixel, may there is aliasing.As shown in Figure 4, between the spectral differences component of the method and amounts of thickness variation, become the relation of approximately linear, thus can utilize the difference between neighbor to calculate adjacent difference component, and then calculate the light path information that surface topography is corresponding.

3, reconstructing method

Obtain after one dimension thickness information, by objective table, sample is rotated, obtain the light path projection information on another projecting direction.Objective table multiple rotary, can obtain the light path information under multiple angles.Three kinds of reconstructing methods of this Information commons:

1. restore fault information with Radon conversion.

2. restore 3 d surface topography information with multi-angle reconstructing method.

3. map out lateral resolution by spectrum coding method from longitudinal frame.

As follows with the concrete grammar of Radon conversion reduction fault information.The fault information that includes part in whole scanning plane in light path projection information due to each angle, after sample multiple rotary, is plotted to this projection information and light path information in same sinogram.According to the principle of CT imaging, sinogram meets center section theorem, can use anti-Radon conversion from sinogram, to restore sectional view, and concrete grammar comprises two kinds of filtered back projection or convolution back projections.

The concrete grammar of filtered back projection is:

1. the g of projection signal (R) of each projecting direction is taken out;

2. g (R) signal is carried out to Fourier transform (can use fast fourier transform or other equivalent changing method) and obtain frequency-region signal;

3. the frequency-region signal after conversion is multiplied by | ρ |, wherein ρ is variable corresponding after radius r Fourier transform;

4. under pair all angles, reuse Fourier transform through the 3rd step projection signal after treatment, semaphore is converted to the territory of making the return trip empty;

5. according to angle separately, spatial domain after treatment signal back projection is formed to reconstructed results.

The concrete grammar of convolution back projection is:

1. the g of projection signal (R) of each projecting direction is taken out;

2. g (R) signal R-L filter function or S-L filter function are carried out to convolution.Wherein the expression formula of R-L function is:

(wherein ρ ₀for cutoff frequency)

${\mathrm{\ρ}}_0^2[2\sin c\left({2\mathrm{\ρ}}_{0}R\right)-{\sin c}^2\left({\mathrm{\ρ}}_{0}R\right)]---\left(8\right)$

The expression formula of S-L function is: (wherein ρ ₀for cutoff frequency)

$\frac{-2}{{\mathrm{\π}}^2{T}^2({4n}^2-1)}---\left(9\right)$

3. according to angle separately, signal after treatment back projection is formed to reconstructed results.

According to the principle of Radon conversion, reconstruct the resolution of image by longitudinal frame, scanning resolution and rotation resolution determine jointly.Relation between resolution and angle coverage and the angular resolution of reconstruction image as shown in Figure 5, (a) be the relation between angle coverage and reconstruction resolution, along with the increase of angle, rebuild resolution and improve gradually, very clear undistorted 140 ° of left and right; (b) be the relation between angular resolution and reconstruction resolution, along with the increase of angle sorting amount, rebuild resolution and improve gradually, very clear undistorted 1-2 ° of left and right.As can be seen from the figure, the resolution of the method after frequency domain conversion is the radial resolution in polar plot corresponding to image, and the angle intervals corresponding angle resolution of rotation.If the angle of rotation is enough meticulous, the lateral resolution of the image of reconstruction can reach the level identical with radial resolution, thereby breaks through the restriction of diffraction limit.

The concrete grammar that restores 3 d surface topography information with multi-angle reconstructing method as shown in Figure 6, (a) corresponding original corrugated, (b) be the corrugated corresponding to angle of reflective light intensity maximum, (c) be the maximum position corrugated corresponding to angle of reflective light intensity maximum, (d) be the line on maximum position corrugated corresponding to the angle of all reflective light intensity maximums in (c), be the corrugated pattern after reconstruction.First rotatable stage, selects the angle (as the α in Fig. 6, β, γ, δ) of some reflective light intensity maximums.Objective table is rotated respectively to this angle, and carry out one-dimensional scanning, obtain reflective light intensity information and optical path difference information under this angle.Utilize this information to draw out respectively the one dimension reflective light intensity curve as shown in curve in Fig. 61.Then in reflective light intensity curve, find out maximum point, and calculate the light path (as shown in curve in Fig. 6 2) at this some place at maximum value place.Optical path length is plotted in the maximum position of light intensity in (as shown in curve in Fig. 6 3), when reconstruct, for each angle, the line segment (as 3 in Fig. 6,4,5,6) that is marked light path rotates through angle (as α, β, γ, δ) separately, obtains postrotational planimetric position (as 7 in Fig. 6,8,9,10).Finally, all planimetric positions are connected to the i.e. cross-section morphology of reducible measured object (as shown in Fig. 6 11).

In Fig. 6, the corresponding line segment of different rotary angle represents by different line styles).Rotation platform turns over different angles, search out several angles of reflective light intensity maximum, and calculate its optical path difference, this optical path difference can represent the distance of reflective surface and reference surface under this angle, both can obtain by bounding method, also can obtain by difference method.When reconstruct, first determine the centre point of a reconstructed image, then describe successively its pattern with continuous line segment.Wherein, catoptrical intensity is proportional to line segment length, and light path is proportional to the distance of line segment and centre point.Each angle is drawn a line segment, and these segment links get up the most at last, i.e. the cross-section morphology of reducible measured object.

For multi-angle reconstructing method is described better, demonstrate the reduction process of this algorithm here by the equilateral triangle nano-micro structure of Eample Analysis length of side 23nm.The numerical aperture of supposing object lens is 0.60, and its aerial aperture angle is 74 degree.When rotation, the relation of the anglec of rotation and intensity of reflected light is as shown in Fig. 7 (a).Find out reflection angle maximum point wherein, in Fig. 7 (a), maximum point is-60 degree points and+60 degree points; Then objective table is turned to these two angles, in Fig. 7 (b), b1 overturn-60 degree, b2 overturn 60 degree; Under these two angles, carry out transversal scanning.When transversal scanning, record optical path difference and reflective light intensity as shown in Fig. 7 (c).Scanning place light intensity is reached to more than threshold value part-be c1 and c2 part in Fig. 7 (c)-be labeled as active position, and record the light path at this some place, then the light path of active position is marked in the reconstruct face figure as shown in Fig. 7 (d), as shown in d1, d2 in Fig. 7 (d).Finally d1 is turned over to-60 degree, d2 turns over 60 degree, then synthetic, obtains the sample section pattern as shown in Fig. 7 (e).

Adopt multi-angle reconstructing method, the variation in thickness that light path detects is corresponding to the radial resolution of reconstructed image, precision is better than 2nm, conversion by from polar coordinate system to cartesian coordinate system, can map out longitudinal frame Δ y and the lateral resolution Δ x of cartesian coordinate system from radial resolution Δ ρ and angle θ corresponding to light intensity extreme value place:

Δy＝Δρ×Sinθ (10)

Δx＝Δρ×Cosθ (11)

Illustrate, the radial resolution Δ ρ that formula (7) obtains is 2nm, and angle θ as corresponding in light intensity extreme value place is 60 degree, and its directions X resolution is to 1nm.

Longitudinal frame is mapped to lateral resolution by spectrum coding method, requires to use broadband illumination, analytic expression uses Fourier transform processing spectrum, obtains the frequency information of spectrum, as shown in Figure 8.Can find out from Fig. 8 (a), optical path difference is larger, and the frequency of reflectance spectrum is higher; Optical path difference is less, and the frequency of reflectance spectrum is lower.By object rotation alpha angle in Fig. 8 (a), and after catoptrical spectrum transverse axis is represented by wave number, carry out Fourier transform and can obtain the frequency spectrum as shown in Fig. 8 (b), each Frequency point represents a thickness, as Fig. 8 (b) intermediate frequency spectrum peak value 1,2,3 interference spectrum of corresponding object 1,2,3 respectively.Utilize the spinfunction of objective table to realize the conversion of longitudinal frame to lateral resolution, concrete steps are as follows:

1. objective table is rotated a certain angle, make to form between reference surface and measurement face the angle of α;

2. use spectrometer measurement reflectance spectrum, and spectrum transform is arrived to wavenumber domain;

3. reflectance spectrum is carried out to Fourier transform, obtain each frequency component amplitude signal;

4. because the frequency of reflectance spectrum is directly proportional to optical path difference, thereby can from frequency, parse the Pixel Information of different longitudinal position;

5. due to the existence of angle between measurement face and reference surface, can extrapolate lateral attitude by lengthwise position:

(wherein lateral attitude, x position, y is lengthwise position)

x＝y/tanα (12)

Therefore,, in the time that the anglec of rotation is different, can obtain different lateral resolutions.In the time that the anglec of rotation reaches or exceed α, lateral resolution can meet or exceed longitudinal frame, thereby realizes horizontal super-resolution imaging.

Claims (7)

1. lateral resolution reaches an interference rotation map detection method of 1nm, it is characterized in that at one the sample surfaces thickness including dynamic sample is interfered to realize according to the following steps in mapping detection system:

Step (1), construct an optical interference structure, by rotation sample, the longitudinal frame mapping of interfering thickness measure is resolved to lateral resolution, for realizing the interference rotation map detection system of three-dimensional ultrahigh resolution imaging, comprising: light source (1), collimating mirror (2), beam splitter (3), the first object lens (41), the second object lens (42), computing machine (5), imaging len (6), sensitive detection parts (7), electronic rotation/translation three-dimensional motion objective table (8), and catoptron (9), wherein:

Light source (1) is laser or other white light source,

Beam splitter (3) is any in level crossing, dichroic mirror or prism,

The first object lens (41), are positioned at length-adjustable gage beam arm end,

The second object lens (42), are positioned at length-adjustable reference arm arm end,

Sensitive detection parts (7), are spectrometer while adopting white light to make light source, while adopting laser to make light source, are CCD device, and the output terminal of described sensitive detection parts (7) is connected with described computing machine (5),

Electronic rotation/translation three-dimensional motion objective table (8), be called for short objective table (8), be positioned under described the first object lens (41), be attached with the microcarrier chip of sample for mounting surface, described objective table (8) is three layers of nested structure, skin is motor actuation movement platform, centre is piezoelectric crystal actuation movement platform, internal layer is rotation sweep platform, microcarrier chip is fixed on internal layer rotation sweep platform, described objective table (8) is under the control of described computing machine (5), complete scanning and rotation to sample on described microcarrier chip, to obtain the full spectral information of each point that sample is had living space,

It is upper that the light that light source (1) sends impinges perpendicularly on described beam splitter (3) after described collimating mirror (2) is collimated into directional light, is divided into transmitted light and reflected light; Described transmitted light converges on described microcarrier chip through described the first object lens (41), after being reflected back, pass through again described the first object lens (41), be collimated into directional light, send to described beam splitter (3), be reflected to after described imaging len (6) is gone up and pool object light; Described reflected light is collimated into after directional light through described the second object lens (42), reflected by described catoptron (9), and then be collimated into directional light through described the second object lens (42), after described beam splitter (3) transmission, pool reference light by described imaging len (6) again; Described object light and reference light coherence stack are received by described sensitive detection parts (7), then send to described computing machine (5), form and interfere high-resolution spectroscopy, are called for short high spectrum;

Step (2), described a kind of lateral resolution reaches the interference rotation map detection method of 1nm, and implementation step is as follows:

Step (2,1), adjusts gage beam and becomes identical optical path length with reference arm, and object light and reference light are interfered;

Step (2,2), described computing machine (5) is controlled described objective table (8), is adjusted to horizontal level, opens described light source (1), obtains the high spectrum of sample;

Step (2,3),, under described computing machine (5) is controlled, described objective table (8) is around horizontal rotational shaft, find out the anglec of rotation α of reflective light intensity maximum point, obtain the high spectrum of interference of sample under described anglec of rotation α;

Step (2,4), the high spectrum of described interference that step (2,3) is obtained, carries out microcarrier chip high spectrum intervention thickness coding/decoding numerical solution, calculates the radial thickness information ρ of sample under anglec of rotation α;

Step (2,5), calculate according to the following formula mapping along slope coordinate y and the lateral coordinates x of sample under anglec of rotation α:

x＝ρ×Cosα，

y＝ρ×Sinα；

Step (2,6), by radial thickness resolution ax ρ, calculates mapping longitudinal frame Δ y and the lateral resolution Δ x of sample under anglec of rotation α according to the following formula:

Δx＝Δρ×Cosα，

Δy＝Δρ×Sinα。

2. a kind of lateral resolution described in step as claimed in claim 1 (2) reaches the interference rotation map detection method of 1nm, it is characterized in that described microcarrier chip high spectrum intervention thickness coding/decoding method, calculate radial thickness by numerical solution, measure radial thickness resolution ax ρ and can reach 1nm.

3. a kind of lateral resolution as claimed in claim 1 or 2 reaches the interference rotation map detection method of 1nm, it is characterized in that restoring fault information with Radon conversion.

4. a kind of lateral resolution as claimed in claim 1 or 2 reaches the interference rotation map detection method of 1nm, it is characterized in that interfering high Spectral Reconstruction to restore 3 d surface topography information by multi-angle.

5. a kind of lateral resolution as claimed in claim 1 or 2 reaches the interference rotation map detection method of 1nm, it is characterized in that, by spectrum coding method, longitudinal frame is mapped to lateral resolution.

6. a kind of lateral resolution described in claim 1 or 2 or 3 or 4 or 5 reaches the interference rotation map detection method of 1nm, it is characterized in that described interference high-resolution spectroscopy is applicable to interference spectrum or the interference fringe of any interference structure device generation of all two part or all of coherence stack in corrugated.

7. a kind of lateral resolution as described in claim 1 or 2 or 3 or 4 or 5 or 6 any one reaches the interference rotation map detection method of 1nm, it is characterized in that described sample is any in biomolecule, abiotic molecule, cell, tissue, virus, microorganism, bacterium, micro-processing structure and nano material.