CN1587898A - Three differential confocal microscopic imaging method and device - Google Patents

Abstract

The invention belongs to micro-imaging and microscopic measurement technical field, relates to a three- differential same focus imaging method and apparatus of axial direction super resolution imaging, comprising light source, special filtering pinpoint hole placed on light source transmitting terminal in turn, measurement micro-objective, besides, its characters include extender placed on light source transmitting terminal, polarization spectroscope, one fourth wave plate placed on the transmission optical path of polarization spectroscope, spectroscope dividing light beam though transmission which is reflected by polarization spectroscope into two light beams and spectroscope combining the two lights together, three condensing mirrors which separately converge three light beams, three pin holes and installed in the position of focal plane front, focal plane and focal plane back in turn, and three photodetectors and separately near the three pinholes.

Description

Three differential confocal microscopic imaging method and device

Technical field:

The invention belongs to micro-imaging and microscopic measurement technical field, the three differential confocal microscopic imaging method and the device that relate to a kind of axial super resolution imaging, it can be used for 3 d surface topography, three-dimensional microstructure, little step, little groove, integrated circuit live width of measuring samples etc.

Background technology:

The thought of confocal microscope is proposed in nineteen fifty-seven first by American scholar M.Minsky the earliest, and obtains United States Patent (USP) in 1961, and the patent No. is US3013467.Confocal microscope places the conjugate position that corresponds to each other with pointolite, some thing and point probe three, and the some illumination and the point that constitute unique chromatography ability in the optical microphotograph imaging are surveyed micro imaging system.The ultimate principle of general confocal microscope as shown in Figure 1, the light that light source 1 sends is reflected by testee after the testee surface is focused into hot spot through pin hole 26, object lens 5, reflected light returns along former road, to import from the flashlight of object by spectroscope 10 again and be positioned in the pin hole 7 of photodetector 8 fronts, forming point at photodetector 8 places detects, the photodetector 8 main flashlights that receive from the object focal point place, the back light beyond the focus is blocked by pin hole 7.When object is positioned at focal plane A, the luminous energy maximum that photodetector 8 receives, when object departs from focal plane A, reflected light is focused a certain position before or after the pin hole, this moment, photodetector 8 only received the sub-fraction luminous energy, that is to say that signal that object detects is than in the focal plane time when out of focus a little less than, so just can change and reflect the position of object with respect to the focal plane by the power that photodetector detects light intensity signal.When object is done scanning motion in the X-Y plane perpendicular to optical axis direction, confocal microscope according to optical axis Z to defocus signal, X to Y to the displacement size, can construct the three-D profile of testee.Confocal microscope has unique tomography ability because of it in the optical microscope imaging, and this just makes it be widely used in fields such as bioengineering, medical science detection, information stores, microelectronics, semiconductor material and surface profile measurement.

Confocal microscope tomography ability is by the halfwidth FWHM decision of axial response curve 27 shown in Figure 2, and FWHM is big more, and the tomography ability is strong more.But owing to be subjected to the restriction of diffraction phenomena, increasing object lens 5 numeric aperture values NA and methods such as reducing optical wavelength λ with traditional passing through, to improve confocal microscope tomography ability extremely limited.For improving the tomography ability of confocal microscope, existing recently numerous unconventional confocal imaging principles and ultra-resolution method are suggested.Aspect the research of confocal microscope, 4PI confocal microscope, θ confocal microscope have appearred and based on the two-photon of optical nonlinearity behavior and multi-photon confocal microscope etc.; Following several class methods have been worked out improving confocal microscope super-resolution imaging technical elements, one class is the Airy disk that reduces by the Rayleigh criterion decision, but do not increase the spatial-cut-off frequency of optical system, technology commonly used comprises: pupil filtering technology, Phase-Shift Masking Technique, based on super resolution technology of optical property nonlinearities change etc.; Second class is by increasing the optical system spatial-cut-off frequency, increase the shared ratio of high frequency light, reducing the Airy disk main lobe of optical system; The 3rd class is by changing the distribution of optical system incident beam spatial frequency, reduce the main lobe of optical system Airy disk, generally can realize by light illumination technology such as off-axis illumination technology, deformation illumination technology, crossed polarized light lighting engineering, ring light lighting engineering and interfering beam space frequency displacement methods.

On the whole, above-mentioned novel confocal microscope and ultra-resolution method have improved the axial resolution characteristic of confocal microscope, satisfied the application demand of the different super-resolution occasions of confocal microscope to a certain extent, but they do not improve significantly to the antijamming capability of confocal microscope, even some method, as the iris filter hyper-resolving method, also can be owing to carrying out the increase that super-resolution causes confocal microscope intensity response characteristic secondary lobe, weaken the antijamming capability of confocal microscope on the contrary, influenced the imaging performance of confocal microscope.

Summary of the invention:

For overcoming the deficiency that above-mentioned existing confocal microscope and axial super resolution technology exist, the invention provides a kind of three differential confocal microscopic imaging method and device that is different from above-mentioned super resolution technology fully, make confocal microscope when improving its tomography ability, can also significantly strengthen the antijamming capability of confocal microscope and improve the range of linearity, have the axial super resolution ability.

Technical solution of the present invention is: a kind of three differential confocal microscopic imaging method comprises the following steps:

(1) the measurement receiving light path with confocal microscope is divided into three tunnel confocal receiving light paths;

(2) three tunnel confocal receiving light paths record the intensity I of the axial response signal with different phasic differences ₂(v, u ,-u _M), I ₁(v, u ,+u _M) and I ₃(v, u, 0) and have the not curve 34,33 and 35 of coordination phase;

(3) with I ₃(v, u, 0) and I ₂(v, u ,-u _M) differential subtract each other I _A(v, u), I ₃(v, u, 0) and I ₁(v, u ,+u _M) differential subtract each other I _B(v, u), I ₂(v, u ,-u _M) and I ₁(v, u ,+u _M) differential subtract each other I _C(v, u), then obtain the intensity I that corresponding sample convex-concave changes (v u) is:

And intensity curved surface 31;

(4) optimize pin hole 18 and pin hole 14 optics normalization coordinate u apart from its corresponding condenser focal position _M, improve the azimuthal resolution of confocal microscope;

(5) (v, the u) light intensity magnitude of intensity curved surface 31 in measurement range reconstruct the 3 d surface topography and the micro-scale of sample according to I.

The present invention also provides a kind of confocal microscopy lens device with axial super resolution, comprise light source 1, be successively placed on the spatial filtering pin hole 26 of light source 1 transmitting terminal, measure microcobjective 5, also comprise the beam expander 2 that is placed on light source 1 transmitting terminal, polarization spectroscope 3, be placed on the quarter-wave plate 4 on polarization spectroscope 3 transmitted light paths, and the spectroscope 10 that the measuring beam after polarization spectroscope 3 reflections is divided into for the first time two bundle measuring light, the spectroscope 12 that the light beam of spectroscope 10 transmissions is divided into once more two bundle measuring beams, converge three condensers 17 of three beams measuring light respectively, 6 and 13, be positioned at the burnt front position of three condensers successively, three pin holes 18 of position of focal plane and defocused position, 7 and 19, and three photodetectors 19 pressing close to three pin hole back respectively, 8 and 15.

Formation method of the present invention and device have following characteristics and good result:

Utilize pin hole axial dipole field to change this character of confocal microscope axial strength response curve phase place, carry out Jiao far away, focal plane and nearly burnt the detection successively by three beams being focused on measuring beam, acquisition has not three measuring-signals of coordination phase, carry out the corresponding differential processing etc. of subtracting each other again, reach and not only improve the confocal microscope system azimuthal resolution but also significantly strengthen environment interference, linearity and out of focus characteristic etc., this is one of innovative point that is different from prior art.

Utilize three detectable signals to carry out data processing and fusion, when making confocal microscope have axial super resolution micro-imaging function, the function that also has the differential confocal measuring system, compare with common confocal microscope, the be more convenient for high-acruracy survey of three-dimensional surface profile and microtexture of three differential confocal microscope, it is measured micro-imaging and merges mutually with surface microscopic profile and dimensional measurement, this be different from prior art innovative point two.

Micro-axial super resolution method of three differential confocal of the present invention and above-mentioned confocal microscope axial super resolution method can organically combine, can be on the basis of above-mentioned super resolution technology, further use the micro-ultra-resolution method of this three differential confocal and carry out super-resolution imaging, this be different from existing super resolution technology innovative point three.

After adopting above-mentioned technology, measurement mechanism has following characteristics:

When 1) improving the confocal microscope system azimuthal resolution, can improve the horizontal out of focus characteristic of confocal microscope system;

2) the differential probe method that subtracts each other of double detector can suppress the common-mode noise that ambient condition difference, light source intensity fluctuation, the electric drift of detector etc. cause, significantly improves signal to noise ratio (S/N ratio), sensitivity and the linearity etc. of measuring system;

3) bipolarity that makes confocal microscope also have the differential confocal measuring system is measured subsidiary function, is convenient to three-dimensional microstructure and surface profile are carried out the absolute tracking measurement of bipolarity.

Description of drawings:

Fig. 1 confocal microscope schematic diagram.

Fig. 2 confocal microscope axial response simulation curve.

Fig. 3 is the inventive method and formation picture of device.

Fig. 4 is a differential wave sensitivity simulation curve.

Fig. 5 works as u for the present invention _M=5.21 o'clock three-dimensional intensity response emulation of confocal microscope curved surfaces.

Fig. 6 works as u for the present invention _M=5.21 o'clock three-dimensional intensity response normalization of confocal microscope emulation curved surfaces.

Fig. 7 is the three-dimensional intensity response normalization of a typical confocal microscope emulation curved surface.

Fig. 8 works as u for the present invention _M=5.21 o'clock confocal microscope axial strength response simulation curves.

Fig. 9 works as u for the present invention _M=5.21 o'clock confocal microscope axial strength response normalization simulation curves.

Figure 10 works as u for the present invention _M=8.0 o'clock confocal microscope axial strength response simulation curves.

Figure 11 works as u for the present invention _M=8.0 o'clock confocal microscope axial strength response normalization simulation curves.

Figure 12 is axial strength response I ₃(v, u, 0), I ₂(v, u ,-u _M) and I ₁(v, u ,+u _M) measured curve, and differential subtract each other curve Ic (0, u) and I (0, u).

Figure 13 is axial strength response I ₃(v, u, 0) and differential subtract each other intensity I (0, normalized curve u).

Wherein, 1 light source, 2 beam expanders, 3 polarization spectroscopes (PBS), 4 quarter-wave plates, 5 object lens, 6,13,17 condensers, 7,14,18,26 pin holes, 8,15,19 photodetectors, 9,11,16 dimmers, 10,12 spectroscopes, the differential normalized unit that subtracts each other of 20,21,22 focus signals, 23 computer processing systems, 24 testees, 25 worktable, 27 confocal microscope axial response curves, 28 sensitivity k _A(0,0, u _M) simulation curve, 29 sensitivity k _B(0,0, u _M) simulation curve, 30 sensitivity k _C(0,0, u _M) simulation curve, 31 three-dimensional intensity response I (v, u) emulation curved surface, the three-dimensional intensity response I of 32 confocal microscopes ₃The emulation curved surface of (v, u, 0), 33 axial strengths response I ₁(0, u ,+u _M) curve, 34 axial strengths response I ₂(0, u ,-u _M) curve, 35 axial strengths response I ₃(0, u, 0) curve, 36 axial strengths response I _C(0, u) curve, 37 axial strengths response I (0, u) curve.

Embodiment:

Introduce method of the present invention below in detail:

Confocal microscope is received measuring beam be divided into three the tunnel, and respectively three condensers are focused on, near three condenser focal planes, respectively arrange a cover photoelectric receiving system, make three cover pin holes and detector be positioned at Jiao far away, focal plane and the nearly burnt position of three condensers successively, constitute confocal microscope Jiao far away, focal plane and nearly burnt three confocal photoelectricity and accept system, that will accept three the tunnel has that the detectable signal of certain phase shift is differential in twos to be subtracted each other and handle again, and reaches the purpose of improving confocal microscope azimuthal resolution and environment interference then.Its concrete technical scheme is as shown in Figure 3: the light that laser instrument 1 sends expands bundle 2 through beam expander, become the p light that the polarization direction is parallel to paper after seeing through polarization spectroscope 3, after these p light transmission quarter-wave plate 4 backs are focused on testee 24 surfaces by object lens 5, returned once more by testee 24 and to see through quarter-wave plate 4 and become the s light of polarization direction perpendicular to paper, polarization spectroscope 3 reflection s light are to spectroscope 10.Spectroscope 10 at first is divided into measuring beam two bundles, and the measuring beam that reflects through spectroscope 10 is focused on by condenser 6, enters the pin hole 7 that is positioned at condenser 6 focal positions, is detected device 8 and receives; Light through spectroscope 10 transmissions is divided into two bundles by spectroscope 12 once more, is focused on by condenser 13 through the measuring beam of spectroscope 12 reflection, enters that distance be the pin hole 14 of M position after condenser 13 focuses, after be detected device 15 receptions; Measuring beam through spectroscope 12 transmissions is focused on by condenser 17, and entering before condenser 17 focuses apart from focal length is the pin hole 18 of M, is received by the detector behind the pin hole 18 19; Differentially subtract each other three signal I that disposal system 20,21 and 22 will detect with a phase bit size ₁(0, u ,+u _M), I ₂(0, u ,-u _M) and I ₃(0, u, 0) differential in twos subtract each other I _A(v, u), I _B(v, u) and I _C(v u), and can get after entering computer processing system 23:

Intensity I (v, u) corresponding sample convex-concave changes, and (v, the u) light intensity magnitude of intensity curve 31 in measurement range reconstruct the 3 d surface topography and the micro-scale of sample, can realize that the axial super resolution confocal microscopic imaging surveys according to I.

Because the redundancy of multiple signals makes confocal microscope except carrying out the axial tomography of super-resolution, utilizes I _c(v, u) the bipolarity measurement function that makes three differential confocal microscope also have the differential confocal measuring system are convenient to three-dimensional microstructure and surface profile are carried out the absolute tracking measurement of bipolarity.

In this axial super resolution three differential confocal microscope, the saturating inverse ratio of spectroscope 10 is 2: 1, and the saturating inverse ratio of spectroscope 12 is 1: 1, and dimmer 9,11 and 16 is respectively applied for regulates the three beams measuring beam, and the light intensity intensity by them is equated.

Above-mentioned three differential confocal microscopy carries out axial super resolution when measuring, and corresponding I (0, the u) u during the azimuthal resolution maximal value _MCan determine by following formula is optimum:

$k\left(\mathrm{0,0}{,u}_M\right)=-\sin c(u_M/4\mathrm{\π})\·\left[\frac{(u_M/4)\·\cos (u_M/4)-\sin (u_M/4)}{{(u_M/4)}^2}\right]$

As shown in Figure 4, work as u _M=± 5.21 o'clock, and sensitivity k (0,0, u _M) corresponding absolute value maximum, and be 0.54.

Principle of the present invention is as shown in Figure 3:

Light source 1, beam expander 2, polarization spectroscope 3, quarter-wave plate 4, object lens 5, condenser 6, pin hole 7 and photodetector 8 constitute confocal microscope, its intensity response I ₃(v, u, 0) is:

$I_3(v,u,0)={\left|\right[2{\∫}_0^{1}P\left(\mathrm{\ρ}\right)\·e^{\left(\mathrm{ju}{\mathrm{\ρ}}^2\right)/2}{J}_0\left(\mathrm{\ρv}\right)\mathrm{\ρd\ρ}\left]\right|}^2\×{\left|\right[2{\∫}_0^{1}P\left(\mathrm{\ρ}\right)\·e^{\left(\mathrm{ju}{\mathrm{\ρ}}^2\right)/2}{J}_0\left(\mathrm{\ρv}\right)\mathrm{\ρd\ρ}\left]\right|}^2---\left(1\right)$

J wherein ₀Be single order Bei Saier function, ρ is the radially radius after the normalization, and axially normalization coordinate u and horizontal normalization coordinate v are:

Wherein, z is that object moves axially distance, and r is the radial coordinate of lens, a ₀Be the numerical aperture of objective angle.

Light source 1, beam expander 2, polarization spectroscope 3, quarter-wave plate 4, object lens 5, condenser 13, pin hole 14 and photodetector 15 constitute detector burnt " the accurate confocal microscope " surveyed far away, its intensity response I ₂(v, u ,-u _M) be:

$I_2(v,u,-u_M)={\left|\right[2{\∫}_0^{1}P\left(\mathrm{\ρ}\right)\·e^{\left(\mathrm{ju}{\mathrm{\ρ}}^2\right)/2}{J}_0\left(\mathrm{\ρv}\right)\mathrm{\ρd\ρ}\left]\right|}^2\×{\left|\right[2{\∫}_0^{1}P\left(\mathrm{\ρ}\right)\·e^{j{\mathrm{\ρ}}^2(u-u_M)/2}{J}_0\left(\mathrm{\ρv}\right)\mathrm{\ρd\ρ}\left]\right|}^2---\left(3\right)$

Wherein, u _MOptics normalization coordinate for corresponding detector axial dipole field condenser focal length M.

Light source 1, beam expander 2, polarization spectroscope 3, quarter-wave plate 4, object lens 5, condenser 17, pin hole 18 and photodetector 19 constitute nearly burnt " the accurate confocal microscope " surveyed of detector, its intensity response I ₁(v, u ,+u _M) be:

$I_1(v,u,+u_M)={\left|\right[2{\∫}_0^{1}P\left(\mathrm{\ρ}\right)\·e^{\left(\mathrm{ju}{\mathrm{\ρ}}^2\right)/2}{J}_0\left(\mathrm{\ρv}\right)\mathrm{\ρd\ρ}\left]\right|}^2\×{\left|\right[2{\∫}_0^{1}P\left(\mathrm{\ρ}\right)\·e^{j{\mathrm{\ρ}}^2(u+u_M)/2}{J}_0\left(\mathrm{\ρv}\right)\mathrm{\ρd\ρ}\left]\right|}^2---\left(4\right)$

When sample 24 carried out axial or transversal scanning with worktable 25, photodetector 8,15 and 19 detected signal I respectively ₃(v, u, 0), I ₂(v, u ,-u _M) and I ₁(v, u ,+u _M), carry out in twos getting behind differential the subtracting each other:

I _A(v，u)＝I ₃(v，u，0)-I ₂(v，u，-u _M) (5)

I _B(v，u)＝I ₃(v，u，0)-I ₁(v，u，+u _M) (6)

I _C(v，u)＝I ₂(v，u，-u _M)-I ₁(v，u，+u _M) (7)

Computer processing system 23 is according to recording I _A(v, u), I _B(v, u) and Ic (v u) measures and judges, the intensity response curve of three differential confocal microscope is:

(convex-concave of corresponding sample 25 changes I in measuring section for v, u) intensity response size, utilizes this value size can reconstruct the surface topography and the micro-scale of sample.

After in a single day systematic parameters such as three differential confocal microscope measurement numerical aperture of objective value, aperture size and detector sensitivity are determined, intensity response curve I _A(0, u), I _B(0, u) and Ic (0, u) sensitivity of hypotenuse linearity range depends primarily on u _M, have a u _MValue makes azimuthal resolution the best of three differential confocal microscope.

To differential wave I _A(0, u) differentiate gets sensitivity k to u _A(0, u, u _M):

$k_A(0,u,u_M)=\sin c\left[(u/2\mathrm{\π})\right]\·\left\{\frac{(u/2)\·\cos (u/2)-\sin (u/2)}{{(u/2)}^2}\right\}-\sin c[(2u-u_M)/4\mathrm{\π}]\·\left\{\frac{\{(2u-u_M)/4\}\·\cos \{(2u-u_M)/4\}-\sin \{(2u-u_M)/4\}}{{\{(2u-u_M)/4\}}^2}\right\}---\left(9\right)$

Slope value k in linearity range _A(0, u, u _M) and k _A(0,0, u _M) equate therefore have:

$k_A(\mathrm{0,0},u_M)=\sin c[\left(u_M\right)/4\mathrm{\π}]\·\left\{\frac{\{\left(u_M\right)/4\}\·\cos \{\left(u_M\right)/4\}-\sin \{\left(u_M\right)/4\}}{{\{\left(u_M\right)/4\}}^2}\right\}---\left(10\right)$

To differential wave I _B(0, u) differentiate gets sensitivity k to u _B(0, u, u _M):

$k_B(0,u,u_M)=\sin c(u/2\mathrm{\π})\·\left\{\frac{(u/2)\·\cos (u/2)-\sin (u/2)}{{(u/2)}^2}\right\}-\sin c[(2u+u_M)/4\mathrm{\π}]\·\left\{\frac{\{(2u+u_M)/4\}\·\cos \{(2u+u_M)/4\}-\sin \{(2u+u_M)/4\}}{{\{(2u+u_M)/4\}}^2}\right\}---\left(11\right)$

Slope value k in linearity range _B(0, u, u _M) and k _B(0,0, u _M) equate therefore have:

$k_B(\mathrm{0,0},u_M)=-\sin c[\left(u_M\right)/4\mathrm{\π}]\·\left\{\frac{\{\left(u_M\right)/4\}\·\cos \{\left(u_M\right)/4\}-\sin \{\left(u_M\right)/4\}}{{\{\left(u_M\right)/4\}}^2}\right\}---\left(12\right)$

To differential wave I _C(0, u) differentiate gets sensitivity k to u _C(0, u, u _M):

$k_C(0,u,u_M)=\sin c[(2u-u_M)/4\mathrm{\π}]\·\left\{\frac{\{(2u-u_M)/4\}\·\cos \{(2u-u_M)/4\}-\sin \{(2u-u_M)/4\}}{\{{(2u-u_M)/4\}}^2}\right\}-\sin c[(2u+u_M)/4\mathrm{\π}]\·\left\{\frac{\{(2u+u_M)/4\}\·\cos \{(2u+u_M)/4\}-\sin \{(2u+u_M)/4\}}{{\{(2u+u_M)/4\}}^2}\right\}---\left(13\right)$

Slope value k in linearity range _C(0, u, u _M) and k _C(0,0, u _M) equate therefore have:

$k_C(0,u,u_M)=-2\sin c[\left(u_M\right)/4\mathrm{\π}]\·\left\{\frac{\{\left(u_M\right)/4\}\·\cos \left\{u_M\right)/4\}-\sin \{\left(u_M\right)/4\}}{{\{\left(u_M\right)/4\}}^2}\right\}---\left(14\right)$

According to formula (10), (12) and (14) respectively with intensity curve I _A(0, u), I _B(0, u) and I _C(0, u) sensitivity curve 28,29 and 30 of linearity range is plotted among Fig. 4, therefrom works as u as can be seen _M=± 5.21 o'clock, sensitivity curve k _A(0,0, u _M), k _B(0,0, u _M) and k _C(0,0, u _M) corresponding absolute value maximum.At this moment, corresponding I _A(0, u), I _B(0, u) and I _C(0, u) the changes in pitch maximum of curve linear section, (0, azimuthal resolution u) is the highest for I.

Fig. 5 is that (v, curved surface u), Fig. 6 are its normalization curved surface to three differential confocal microscope intensity response I.Fig. 7 is corresponding typical confocal microscope intensity response I ₃The curved surface of (v, u, 0) is with I ₃(v, u, 0) compare I (v, response curve u) obviously obtains sharpening, (v, u) 〉=0 Yi Shang secondary lobe obviously is inhibited I.Fig. 8 is for working as u _M=5.21 o'clock, I ₁(0, u ,+u _M), I ₂(0, u ,-u _M), I ₃(0, u, 0), I _C(0, u) and I (0, response curve 33,34,35,36 and 37 u), Fig. 9 is u _M=5.21 o'clock, I ₁(0, u ,+u _M), I ₂(0, u ,-u _M), I ₃(0, u, 0), I _C(0, u) and I (0, normalized response curve 33,34,35,36 and 37 u).As can be seen from Figure 9, (0, u) halfwidth of curve 37 is significantly less than I to I ₃The halfwidth of (0, u, 0) curve 35, promptly the azimuthal resolution of confocal microscope improves, and (0, u) linearity of two hypotenuse descending brancies also improves curve I simultaneously.Because I (0, u) be I ₃(0, u, 0), I ₂(v, u ,-u _M) and I ₁(v, u ,+u _M) differential in twos subtracting each other obtains between the intensity response curve, thereby factor such as confocal microscope light-intensity variation, sample surfaces reflectance varies, environmental interference is to intensity response curve I (0, u) influence greatly reduces, thereby significantly improved the environment interference of confocal microscope, this advantage is that existing axial super resolution confocal microscope is incomparable.

Certain u _MSelection should take all factors into consideration, simultaneously also should consider that (Figure 10 is u to I for v, light intensity magnitude u) _M=8.0 o'clock axial strength response curve, Figure 10 compares with Fig. 8, although (0, u) halfwidth of intensity response curve may be little, and the light intensity value of Figure 10 is big, therefore, selects u for I among Fig. 9 _MThe time should take into account u _MInfluence to axial super resolution effect and light intensity magnitude two aspects.

Below the structure of the three differential confocal microscope device of axial super resolution of the present invention and principle of work being reached accompanying drawing in conjunction with the embodiments is described in detail as follows: a kind of three differential confocal microscope device of axial super resolution, comprise light source 1, be successively placed on the beam expander 2 of light emitted end, spatial filtering pin hole 26, polarization spectroscope 3, be placed on the quarter-wave plate 4 on polarization spectroscope 3 transmitted light paths, object lens 5, and the spectroscope 10 that the measuring beam after polarization spectroscope 3 reflections is divided into for the first time two bundle measuring light, the spectroscope 12 that the light beam of spectroscope 10 transmissions is divided into once more two bundle measuring beams, converge three condensers 17 of three beams measuring light respectively, 6 and 13, be positioned at the burnt front position of three condensers successively, three pin holes 18 of position of focal plane and defocused position, 7 and 14, and three photodetectors 19 pressing close to three pin hole back respectively, 8 and 15 form.The present invention's three differential shafts also comprise the differential disposal system 20,21 and 22 of three focus signals that links to each other successively to the super-resolution confocal microscope, a computing machine processing and amplifying system 23, wherein the differential disposal system of focus signal links to each other with photodetector, the transducing signal that receives after processing and amplifying, is carried out data processing again by computing machine.The present invention's three differential shafts are in the super-resolution confocal microscope, and the saturating inverse ratio of spectroscope 10 is 2: 1, and the splitting ratio of spectroscope 12 is 1: 1, and dimmer 9,11 and 16 is respectively applied for regulates the three beams measuring beam, makes their light intensity equal substantially.

Present embodiment: object lens 5 are preferentially selected 60 * 0.85 common flat field achromatic micro objective for use.Photodetector 8,15 and the 19 preferential 2001 type photelectric receivers that adopt U.S. NEWFOCUS company to produce, the saturation power scope is 10mW, the maximum adjustable gain is 10 ⁴, the minimal noise equivalent power is 0.25pW/Hz ^1/2

Pin hole 7,14 and 18 is preferentially selected the PH-10 type pin hole of U.S. NERPORT company for use, and it is made of ultra-thin Mo, and aperture size is 10 μ m, and thickness is 15.24 μ m.

The driver of micro-displacement work table 25 select preferentially that U.S. NEWFOCUS company produces for use on a large scale, the high stability micro-displacement driver, the flexible hinge work bench that is equipped with scale down and is 5: 1 is formed nano level fine motion calibration system, and each driving pulse of micro-displacement driver can obtain the feeding of 2nm.

Axial super resolution performance to present embodiment axial super resolution three differential confocal microscope device makes a preliminary test, measured object is selected gauge block for use, gauge block is placed on the objective table, adjust step vertically by micro-adjusting mechanism, the light contact is focused on the gauge block surface, then, displacement gauge block vertically, the resolving power of micro displacement workbench is 2nm, detect the amount of movement of gauge block with the HP5529A two-frequency laser interferometer, its resolving power is 0.001 μ m, and drive system can be the amount of feeding fine motion step of 0.01 μ m with resolving power.

Figure 12 is that the intensity that records is I ₁(0, u ,-u _M), I ₂(0, u ,+u _M) and I ₃The curve 34,33 and 35 of (0, u, 0), and I ₁(0, u ,-u _M), I ₂(0, u ,+u _M) and I ₃The differential intensity that obtains of subtracting each other is I between (0, u, 0) _C(0, u) and I (0, curve 36 and 37 u), Figure 13 are I ₃(0, u, 0) and I (0, u) normalized curve 35 and 37, obviously compare with confocal microscope intensity response curve 35, the halfwidth of three differential confocal microscope axial strength response curve 37 of the present invention significantly reduces, and linearity significantly improves, measurement result and aforementioned theoretical analysis and simulation curve basically identical.

Claims (9)

1. a three differential confocal microscope formation method is characterized in that comprising the following steps:

(1) the measurement receiving light path with confocal microscope is divided into three tunnel confocal receiving light paths;

(2) three tunnel confocal receiving light paths record has the not intensity I of the axial response signal of coordination phase ₂(v, u ,-u _M), I ₁(v, u ,+u _M) and I ₃(v, u, 0) and have the not intensity curve of coordination phase (34), (33) and (35);

(3) with I ₃(v, u, 0) and I ₂(v, u ,-u _M) differential subtract each other I _A(v, u), I ₃(v, u, 0) and I ₁(v, u ,+u _M) differential subtract each other I _B(v, u), I ₂(v, u ,-u _M) and I ₁(v, u ,+u _M) differential subtract each other I _C(v, u), then obtain the intensity I that corresponding sample convex-concave changes (v u) is:

And intensity curved surface (31);

(4) preferred pin hole (18) and pin hole (14) are apart from the optics normalization coordinate u of its corresponding condenser focal position _M, improve the azimuthal resolution of confocal microscope;

(5) (v, the u) light intensity magnitude of intensity curved surface (31) in measurement range reconstruct the 3 d surface topography and the micro-scale of sample according to I.

2. method according to claim 1 is characterized in that said step (1) for earlier measuring beam being divided into two bundle measuring beams, again with a branch of two bundle measuring beams that are divided in the two bundle measuring beams.

3. method according to claim 1 and 2 is characterized in that also comprising and utilizes I _C(v u) carries out the bipolarity absolute measurement of three-dimensional microstructure and surface profile.

4. method according to claim 1 and 2, it is characterized in that corresponding I (0, u) and I _C(0, the u) u during the azimuthal resolution maximal value _MDetermine by following formula is optimum:

$k(\mathrm{0,0},u_M)=-2\·\sin c(u_M/4\mathrm{\π})\·\left[\frac{(u_M/4)\·\cos (u_M/4)-\sin (u_M/4)}{{(u_M/4)}^2}\right]$

Work as u _M=± 5.21 o'clock, and I (0, u) and I _C(0, u) hypotenuse section Sensitirity va1ue maximum.

5. three differential confocal microscope imaging device, comprise light source (1), be successively placed on the spatial filtering pin hole (26) of light source (1) transmitting terminal, measure microcobjective (5), it is characterized in that also comprising the beam expander (2) that is placed on light source (1) transmitting terminal, polarization spectroscope (3), be placed on the quarter-wave plate (4) on polarization spectroscope (3) transmitted light path, and the spectroscope (10) that the measuring beam after polarization spectroscope (3) reflection is divided into for the first time two bundle measuring light, the spectroscope (12) that the light beam of spectroscope (10) transmission is divided into once more two bundle measuring beams, converge three condensers (17) of three beams measuring light respectively, (6) and (13), be positioned at the burnt front position of three condensers successively, three pin holes (18) of position of focal plane and defocused position, and three photodetectors (19) of pressing close to three pin hole back respectively (7) and (14),, (8) and (15).

6. device according to claim 5, it is characterized in that also comprising three the differential disposal systems of focus signal (20), (21) and (22) that link to each other successively, a computing machine processing and amplifying system (23), wherein the differential disposal system of focus signal (22) links to each other with photodetector (8), after the transducing signal amplification that receives, carry out data processing again by computing machine.

7. device according to claim 5 is characterized in that this confocal microscopy lens device also comprises dimmer (9), (11) and (16), is respectively applied for to regulate the three beams measuring beam, and their light intensity is equated.

8. according to claim 5 or 6 or 7 described devices, the saturating inverse ratio that it is characterized in that spectroscope (10) is 2: 1.

9. according to claim 5 or 6 or 7 described devices, the saturating inverse ratio that it is characterized in that spectroscope (12) is 1: 1.

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