CN1920614A - Apparatus and method for generating an array of spatial light spots using a polygon mirror and a polygon stage mirror - Google Patents

Abstract

The invention relates to a device and a method for generating a plurality of coherent light beams to interfere and form a two-dimensional and three-dimensional optical grid by using a multi-pyramid mirror and a multi-frustum mirror. The laser beam emitted by a common laser generates parallel coherent light beams after beam expansion and collimation, the light beams enter the bottom surface of a regular polygon mirror or a polygon stage mirror with specific edge number and bottom angle number, the light beams can be split and deflected on each conical surface when passing through a glass pyramid/stage mirror, each sub-light beam can generate multi-light beam interference after exiting the pyramid/stage mirror so as to generate a two-dimensional or three-dimensional light spot array, the included angle of each light beam is determined by the bottom angle of the pyramid/stage, and the number of the light beams is determined by the edge number. Compared with the prior art, the invention has the advantages of simple use, low manufacturing cost, easy integration, good stability, high transmittance, high damage threshold and wide application range.

Description

Produce the equipment and the method for space light spots array with polygonal pyramid mirror and many terrace with edges mirror

Technical field

The present invention relates to a kind of polygonal pyramid mirror and many terrace with edges mirror of using and produce equipment and the method that the multi beam coherent light interference forms the two and three dimensions optical lattice.

Background technology

Photonic crystal is that two dimension or the three dimensions cycle that a kind of high refractive index contrast material forms is the periodic micro structure of wavelength magnitude, it can produce specific forbidden photon band, when light is propagated therein, can produce many peculiar phenomenons, thereby very tempting application prospect be arranged in fields such as optical waveguide, optical storage, optical communications.The making visible light is a present primary study direction to the photonic crystal of near-infrared band, and the preparation method has a lot, and as optical semiconductor lithography, ion beam etching, chemical etching, Laser Micro-Machining etc., but these methods all need expensive equipment.Laser is owing to have good coherence, interfere the light intensity periodic lattice that produces to distribute with multiple laser and have the very high degree of order, and, can produce the cycle lattice battle array of one dimension miscellaneous, two and three dimensions light distribution by changing light beam number, the direction of propagation and the polarization state of laser.This light intensity period profile lattice battle array that laser space interference light field forms is called as optical lattice.This method is made photonic crystal or optical microstructures device, and to have equipment simple, but advantages such as one-step shaping are subject to people's attention in recent years.1997, two-dimentional hexangle type periodic structure was made in three grating pair incident laser diffraction formation three beams plane wave interference of 60 degree angles each other on the human planes such as Berger in GaAs.Calendar year 2001 and 2003, Kondo group uses femtosecond laser and diffraction beam splitter to produce the four bundle interference of light, utilizes single photon and two-photon absorption effect successfully to prepare two dimension and three-dimensional sub-micron cycle crystalline network on SU8 photoresist material respectively.People such as physics institute of Chinese Academy of Sciences journey third English use the way simulation of laser space interference to produce lattice pattern, and it has been carried out Analysis on Mechanism and computer simulation.Cai of Shandong University carries out medium people and has proved that four non-coplane beam interferences can form all 14 kinds of Bravias lattice, and has carried out theory and experimental study.People such as the Wang Xia of Zhongshan University have carried out theoretical analysis to laser polarization state to the influence of interference figure contrast, and use argon laser to make three-dimensional face-centred cubic structure on SU8 photoresist material.The people such as Zhang Jin of Sichuan University and photoelectric technology research institute of the Chinese Academy of Sciences also utilize this method to carry out the research of large tracts of land periodic pattern photoetching technique.Make it interfere the light path adjusting and stable experiment porch that needs precision owing in experiment, from beam of laser, telling the aplanatic light beam of multi beam and regulating, restraint interference of light so great majority research is limited to 3-6.Though diffraction beam splitter can obtain multiple beam, because its transmitance is not high and processing difficulty, laser power can be lost a lot and zlasing mode also can variation, and its cost of manufacture is also higher relatively.

Summary of the invention

The object of the invention provides a kind of equipment and method of using polygonal pyramid mirror or many terrace with edges mirror to produce multiple beam, its solved prior art produce multiple beam need accurate light path regulate, processing not high with stable experiment porch, transmitance difficulty, laser power can lose much and zlasing mode also can variation, the relative higher shortcoming of cost of manufacture.

Technical solution of the present invention is:

A kind of polygonal pyramid mirror and many terrace with edges mirror used produces the equipment of space light spots array, but comprises the laser instrument 1 of emission of lasering beam, and its special character is that it also comprises the polygon prism 3 that is arranged on the laser beam transmit direction.

The said equipment also can comprise the beam-expanding collimation instrument 2 that is arranged on the laser beam transmit direction, and described beam-expanding collimation instrument 2 is arranged between laser instrument 1 and the polygon prism 3.

Above-mentioned beam-expanding collimation instrument 2 comprises extender lens group 6 and collimation lens set 7.

Above-mentioned extender lens group 6 comprises convex lens at least, and described collimation lens set 7 comprises convex lens at least; Distance between described extender lens group 6 and the collimation lens set 7 is its focal length sum.

Above-mentioned polygon prism 3 is polygonal pyramid mirror 4 or many terrace with edges mirror 5.

Above-mentioned laser instrument 1 is various pulses or continuous laser instrument.

A kind of method with polygonal pyramid mirror generation space light spots array may further comprise the steps:

1] gets a polygonal pyramid mirror;

2] laser instrument emission of lasering beam;

3] laser beam is entered the polygonal pyramid mirror from polygonal pyramid mirror bottom surface vertical incidence, form the multipath interference light beam through refraction.

A kind of many terrace with edges of usefulness mirror produces the method for space light spots array, may further comprise the steps:

1] gets terrace with edge mirror more than;

2] laser instrument emission of lasering beam;

3] laser beam is entered many terrace with edges mirror from many terrace with edges mirror bottom surface vertical incidence, form the multipath interference light beam through refraction.

Can carry out beam-expanding collimation before the above-mentioned laser beam incident.

Advantage of the present invention is:

1, use simply, cost of manufacture is low.The present invention adopts ordinary optical glass as raw material, and making and use are all fairly simple, and cost is lower than the grating or the diffraction beam splitter of prior art.

2, be easy to integrated, good stability.The present invention at most only needs two optical device except laser instrument, so be easy to be integrated on other instrument and equipments, its stability is better than the discrete device that is arranged on the optical table.

3, transmitance height, the damage threshold height.The transmitance of optical glass is up to 98%, and the general grating or the transmitance of diffraction beam splitter have only about 50%.Damage threshold is meant the damage threshold of laser to element, because the present invention is for the optical glass making, so have very high damage threshold.

4, applied range.The present invention uses laser beam irradiation polygonal pyramid mirror or many terrace with edges mirror to realize that multiple-beam interference produces the two and three dimensions array of light spots, not only can be used for the manufacturing of optical microstructures such as photonic crystal, array optical waveguide, and in biomedical sector, can be used for producing multiple beam light tweezer, catch simultaneously and operate a plurality of fine particles, expand the purposes of common single beam light tweezer.And, also can be used for the research of cell sorting and biochip technology because its volume is easy to advantages such as integrated for a short time.

5, can be used for various pulses or continuous laser instrument.

The explanation of accompanying drawing drawing

Fig. 1 is this unit construction principle synoptic diagram;

Fig. 2 is that the m bundle is interfered synoptic diagram along z rotational symmetry distribution plane wave;

Fig. 3 is that the m+1 bundle is interfered synoptic diagram along z rotational symmetry distribution plane wave;

Fig. 4 is the plane geometry light path synoptic diagram that directional light passes through the pyramid mirror;

Fig. 5 is that the rectangular pyramid mirror forms the multiple-beam interference synoptic diagram;

Fig. 6 is that the truncated rectangular pyramids mirror forms the multiple-beam interference synoptic diagram;

Fig. 7 is the two-dimentional array of light spots synoptic diagram that the positive triangular axicon lens of laser incident produces;

Fig. 8 is the three-dimensional light lattice array synoptic diagram that the positive three terrace with edge mirrors of laser incident produce;

Fig. 9 is the two-dimentional array of light spots synoptic diagram that the positive rectangular pyramid mirror of laser incident produces;

Figure 10 is the three-dimensional light lattice array synoptic diagram that the positive truncated rectangular pyramids mirror of laser incident produces;

Wherein: 1-laser instrument, 2-beam-expanding collimation instrument, 3-polygon prism, 4-polygonal pyramid mirror, many terrace with edges of 5-mirror, 6-extender lens group, 7-collimation lens set.

Embodiment

But present device comprises the laser instrument 1 and the beam-expanding collimation instrument 2, the polygon prism 3 that are successively set on the laser beam transmit direction of emission of lasering beam.Laser instrument 1 can be various pulses or continuous laser instrument, polygon prism 3 can be polygonal pyramid mirror 4 or many terrace with edges mirror 5, its rib number can be digonous, triangular, four ribs, five ribs, six ribs ... Deng, increase along with the rib number, the pattern of dot matrix also can change, the structure that the pyramid of different rib numbers produces dot matrix is different, and wherein the two-dimentional array of light spots that produces of triangular axicon lens sees that two-dimentional array of light spots that three-dimensional light lattice array that Fig. 7, three terrace with edge mirrors produce sees that Fig. 8, rectangular pyramid mirror produce sees that the three-dimensional light lattice array that Fig. 9, truncated rectangular pyramids mirror produce sees Figure 10.Beam-expanding collimation instrument 2 can expand bundle and collimation to laser beam, beam-expanding collimation instrument 2 can adopt various ways, relatively more commonly used is to adopt two groups of lens, wherein one group is extender lens group 6, another group is collimation lens set 7, and the simplest implementation is two convex lens, wherein is used for expanding bundle from the near convex lens of laser instrument, be used for collimating from laser instrument convex lens far away, and the focus of two convex lens overlaps on the Laser emission direction.Be not less than 5mm if laser instrument emitted laser bundle is parallel laser beam (angle of divergence is very little) and beam diameter, present device can be without the beam-expanding collimation instrument, and laser beam is directly incident on the bottom surface of polygon prism.

The polygonal pyramid mirror of this equipment or many terrace with edges mirror are made of ordinary optical glass, quartz or other transparent optical material, are processed into positive polygonal pyramid mirror or many terrace with edges mirror of the specific rib number and the base angle number of degrees through operations such as optics cutting, grinding, polishing, plated films.The parallel coherent light beam incident polygonal pyramid mirror or the bottom surface of many terrace with edges mirror, can beam splitting on each conical surface when die glasvertafelte pyramide/platform mirror and deviation takes place, produce two dimension or three-dimensional array of light spots thereby multiple-beam interference can take place each divided beams behind outgoing pyramid/platform mirror.The angle of each light beam is by the base angle decision of pyramid/platform, and the number of light beam is determined by the rib number.

With positive rectangular pyramid mirror is example, as shown in Figure 5, the bottom surface of laser beam normal incidence pyramid behind beam-expanding collimation, incident light is refracted on four conical surfaces, form the four bundles symmetrical distribution plane wave identical with optical axis included angle, and their amplitude is also all identical with initial phase.In the back of pyramid, they have one section crossing zone, form interference region at this.In order to produce m+1 bundle light shown in Figure 3, we polish polishing with the top of pyramid, make it can directly see through a part of incident light and form m+1 bundle light, as shown in Figure 6.

Embodiment 1

Use the positive triangular axicon lens of He-Ne laser radiation base angle 5 degree of wavelength 633nm, can obtain periodicity two dimension array of light spots as shown in Figure 7.Use the positive three terrace with edge mirrors of He-Ne laser radiation base angle 5 degree of wavelength 633nm, can obtain periodicity three-dimensional light lattice array as shown in Figure 8.

Embodiment 2

Use the positive rectangular pyramid mirror of He-Ne laser radiation base angle 2 degree of wavelength 633nm, can obtain periodicity two dimension array of light spots as shown in Figure 9.Use the positive truncated rectangular pyramids mirror of He-Ne laser radiation base angle 2 degree of wavelength 633nm, can obtain periodicity three-dimensional light lattice array as shown in figure 10.

The multi beam plane wave can produce two dimension or three-dimensional space light spots array distribution in the spatial coherence stack.When each angle of beams hour (＜10 °), can be similar to and think that the polarization state of each light beam is all identical.If angle of beams does not satisfy the low-angle situation, must consider of the influence of the polarization state relationship of each light beam when then calculating to the interference optical field contrast.For principle of specification, we only consider respectively to restraint the identical situation in plane wave polarization direction here, and can handle this moment with scalar wave.If the complex amplitude of j bundle plane wave is:

$E_j\left(\stackrel{\→}{r}\right)=E_j\exp (i{\stackrel{\→}{K}}_j\·\stackrel{\→}{r}+i{\mathrm{\δ}}_j)---\left(1\right)$

E wherein _jExpression electric field intensity amplitude, Be position vector,

Be wave vector, δ _jIt is initial phase.If θ _jAnd φ _jExpression respectively With z axle clamp angle and at the angle of xy plane inner projection and x axle, λ represents wavelength, then

${\stackrel{\→}{K}}_j=\frac{2\mathrm{\π}}{\mathrm{\λ}}[\sin {\mathrm{\θ}}_j\cos {\mathrm{\φ}}_j,\sin {\mathrm{\θ}}_j,\cos {\mathrm{\θ}}_j]---\left(2\right)$

Be provided with m bundle and interfere along the plane wave that the z rotational symmetry distributes, as shown in Figure 2, respectively restrainting the wave vector of plane wave this moment all identical with z axle clamp angle (is θ ₁=θ ₂=...=θ _m=θ), each restraints that the plane wave wave vector divides equally 360 ° of circumference in the projection on xy plane (is φ _j=360 ° of * (j-1)/m, j=1...m).So the z of each wave vector is identical to component, interference field does not change along the z direction of principal axis, and interference field only forms two-dimensional and periodic and distributes on the xy plane.Electric field intensity complex amplitude after the interference is:

$E_{\mathrm{tot}}\left(\stackrel{\&RightArrow;}{r}\right)={\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="A20051004314600101.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="A20051004314600101.png"\; state="\{\{state\}\}">E</figure-callout>}}_2+....+E_m---\left(3\right)$

Light distribution is:

$I\left(\stackrel{\&RightArrow;}{r}\right)={\left|E_{\mathrm{tot}}\right|}^2=E_{\mathrm{tot}}\&CenterDot;E_{\mathrm{tot}}^{*}---\left(4\right)$

If on the basis of Fig. 2 beam configuration, introduce a branch of plane wave K that propagates along the z axle again _M+1As shown in Figure 3, because m+1 bundle light is propagated along the z axle, its z axle wave vector component is different with other m bundle z axle wave vector component, so this moment, interference field was except forming on the xy plane the periodic distribution, also have cyclical variation along the z direction of principal axis, this moment, this m+1 bundle interference of light meeting formed the three-dimensional optical lattice in the space.Light distribution after the interference of light of m+1 bundle is:

$I\left(\stackrel{\&RightArrow;}{r}\right)=|{\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="A20051004314600101.png"\; state="\{\{state\}\}">E</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="A20051004314600101.png"\; state="\{\{state\}\}">E</figure-callout>}}_2+....+E_m+E_{M+1}{|}^2---\left(5\right)$

Following surface analysis is the character of interference optical field once.As shown in Figure 4, radius is that the parallel beam vertical symmetry incident base angle of w0 is the pyramid (terrace with edge) of γ, and direction of beam propagation is defined as the z axle, is defined as the x axle perpendicular to the z direction of principal axis on the paper.Incident beam can interfere in illustrated shadow region after pyramid (terrace with edge) refraction beam splitting, forms the two-dimensional and periodic pattern (pyramid situation) that does not have variation along the z direction of principal axis, or along the z axle periodically variable three-dimensional periodic pattern (terrace with edge situation) is arranged also.Interference region in the axial length of z is:

Z _max＝w ₀/tgθ (6)

Wherein θ represents deflecting light beams E ₁(or E ₂) with the angle of z axle.In order to obtain long interference region, the base angle of pyramid processes very for a short time usually, and approximation relation is arranged this moment:

θ≈(n-1)γ (7)

Wherein n is the refractive index of axicon lens.For the m+1 light beams that terrace with edge produces, the intensity modulation cycle that forms in the z direction is:

d _z＝λ/(1-cosθ)≈2λ/[(n-1)γ] ² (8)

Three-dimensional lattice square is inversely proportional to cycle of z direction and pyramid mirror base angle, and the xy plane lattice cycle is also relevant with the pyramid base angle, and the pyramid base angle is big more, and the light lattice cycle of formation is more little, but interference region is also more little.Use short wavelength's laser (as Ultra-Violet Laser) can obtain little optical lattice of cycle.

Claims (9)

1, a kind of polygonal pyramid mirror and many terrace with edges mirror used produces the equipment of space light spots array, but comprises the laser instrument (1) of emission of lasering beam, and it is characterized in that: described equipment also comprises the polygon prism (3) that is arranged on the laser beam transmit direction.

2, the equipment that produces space light spots array with polygonal pyramid mirror and many terrace with edges mirror according to claim 1, it is characterized in that: described equipment also comprises the beam-expanding collimation instrument (2) that is arranged on the laser beam transmit direction, and described beam-expanding collimation instrument (2) is arranged between laser instrument (1) and the polygon prism (3).

3, the equipment with polygonal pyramid mirror and many terrace with edges mirror generation space light spots array according to claim 2, it is characterized in that: described beam-expanding collimation instrument (2) comprises extender lens group (6) and collimation lens set (7).

4, the equipment with polygonal pyramid mirror and many terrace with edges mirror generation space light spots array according to claim 3, it is characterized in that: described extender lens group (6) comprises convex lens at least, described collimation lens set (7) comprises convex lens at least; Distance between described extender lens group (6) and the collimation lens set (7) is its focal length sum.

5, according to the described equipment with polygonal pyramid mirror and many terrace with edges mirror generation space light spots array of arbitrary claim of claim 1 to 4, it is characterized in that: described polygon prism (3) is polygonal pyramid mirror (4) or many terrace with edges mirror (5).

6, the equipment with polygonal pyramid mirror and many terrace with edges mirror generation space light spots array according to claim 5, it is characterized in that: described laser instrument (1) is various pulses or continuous laser instrument.

7, a kind of method with polygonal pyramid mirror and many terrace with edges mirror generation space light spots array, it is characterized in that: described method comprises:

1] gets a polygonal pyramid mirror;

2] laser instrument emission of lasering beam;

3] laser beam is entered the polygonal pyramid mirror from polygonal pyramid mirror bottom surface vertical incidence, form the multipath interference light beam through refraction.

8, a kind of method with polygonal pyramid mirror and many terrace with edges mirror generation space light spots array, it is characterized in that: described method comprises:

1] gets terrace with edge mirror more than;

2] laser instrument emission of lasering beam;

3] laser beam is entered many terrace with edges mirror from many terrace with edges mirror bottom surface vertical incidence, form the multipath interference light beam through refraction.

9, according to claim 7 or 8 described methods, it is characterized in that: can carry out beam-expanding collimation before the described laser beam incident with polygonal pyramid mirror and many terrace with edges mirror generation space light spots array.

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