CN204215107U - Based on the hyperchannel space structure light field generating apparatus of improved Mechelson interferometer - Google Patents

Abstract

The utility model is a kind of hyperchannel space structure light field generating apparatus based on improved Mechelson interferometer, it is characterized in that: light source is introduced Michelson interferometer system by the positive and negative one-level of liquid crystal cell diffraction, two-face mirror simultaneously in Michelson interferometer is improved: one is replaced by total reflection prism and realizes exchanging of the positive and negative order of diffraction time propagation light path, and required ± 1 order diffraction selected by placement space wave filter before total reflection prism; Another side catoptron becomes only reflection level time, can complete the control for position phase and polarization so simultaneously, thus achieve multichannel spatial light field generating apparatus in a set of light path.On the other hand simultaneously, for the method for coherence stack regulation and control polarization, directly can carry out the simple and efficient switching realizing basic vector by the method removed and add quarter-wave plate (or other phase light elements are as spiral position photo etc.), facilitate follow-up being widely used in variously to have mutually in the experiment of particular demands with position light source polarization.

Description

Based on the hyperchannel space structure light field generating apparatus of improved Mechelson interferometer

Technical field

The utility model relates to spatial light field and generates new technology, and design achieves a set of hyperchannel space structure light field generating apparatus that simultaneously can regulate and control light field polarization and position phase.

Background technology

The light field that different from conventional light field, space structure light field is amplitude, polarization and position have specific distribution mutually in space.The singularity of its polarization and position phase, brings the optical property of series of novel, thus optical communication can be applied to, light catches and optics manufacture etc., generation technique and the applied research of space structure light field attract wide attention.

The light field in space structure light field with particular polarization distribution is referred to as vectorial field, and it is the special light field that a kind of polarization state changes along with locus.The method generating vectorial field mainly contains two large classes: one, by designing the cavity configuration of laser instrument inside, introduces special optical element, and the vectorial field directly obtaining AD HOC exports; Its two be interfere method, based on Poincare sphere polarized combination theory, utilize a pair mutually orthogonal polarization basic vector coherence stack to obtain different vectorial fields.For first method, maximum shortcoming lacks dirigibility, after laser cavity structure design is determined, can only obtain the light field of the AD HOC of its correspondence.Comparatively speaking, the vectorial field that second method generates has more dirigibility, and almost can obtain the vectorial field of arbitrary form by LCD space light modulator (Spatial Light Modulator, SLM).

On the other hand, there is the light field of specific phase distribution as vortex light field and salt free ligands light field etc. in space structure light field, the features such as the stability of the center singular point, controlled orbital angular momentum and the spatial that bring due to its phase character, have huge application potential in the field such as optical communication, optical manipulation.Nineteen ninety-five, experimentally just existing people (the Direct Observation of Transfer of Angular Momentum to Absorptive Particles from a Laser Beam with a Phase Singularity that observes that the orbital angular momentum of vortex beams can interact with fine particle, Phys.Rev.Lett., 1995,, thus cause photic rotation 75 (5): 826-829.).Current optical eddy has been widely used in optical micro-manipulation technology, and the optics as fine particle rotates, imprison and guiding etc.And be propose (Exact solutions for nondiffracting beams (I): The scalar theory.JOSA A by Durnin J in 1987 by the salt free ligands light field that position regulates and controls to obtain mutually, (4), 65l-654 (1987)), this light beam hot spot cross direction profiles in communication process remains unchanged, and makes it have good application prospect in fields such as Laser Processing, optical alignment and light tweezers.

About the method that vectorial field generates, the people such as Stefan Bernet as far back as Univ Innsbruck in 2007 just proposes a kind of optical interference circuit (Tailoring of arbitrary optical vector beams.New J.Phys. utilizing Wollaston prismatic decomposition based on LCD space light modulator device, 2007, 9.) generate complicated Laguerre-Gauss vectorial field: after incident light constant amplitude is divided into two bundles by Wollaston prism, the polarization controlling two-beam more respectively makes its mutually orthogonal formation a pair basic vector, incide the left-right parts of the liquid crystal panel of spatial light modulator, obtain respectively contrary vortex position mutually after be reflected back again on Wollaston prism close bundle, achieve the generation of complicated Laguerre-Gaussian beam.Liquid crystal panel due to the method is divided into two regions, left and right, loads different phase mehtod respectively, thus greatly reduces the resolution of liquid crystal modulation position phase.On this basis, 4F system (the Generation of arbitrary vector beams with a spatial light modulatorand a common path interferometric arrangement.Optics Letters of a set of vectorial field for generating random polarization distribution has successfully built by LCD space light modulator equally in the Wang Hui field group of Nankai University, Vol.32, Issue 24, pp.3549-3551 (2007)): the holographic grating comprising spiral position phase is directly carried on liquid crystal panel, incident light is through liquid crystal surface diffraction, its ± 1 grade of condition namely meeting coherence stack, the quarter-wave plate of recycling two mutually orthogonal placements regulates the ± polarization direction of 1 grade further, it is made to form pair of orthogonal basic vector.Compare the work of the people such as Stefan Bernet, this cover light path takes full advantage of the resolution of liquid crystal panel, but the shortcoming of this method is because the holographic grating cycle is larger, on grating frequency plane ± space length of 1 grade is very close, therefore the slit separation wherein as filter element is very little, and need in the behind of two slits place two quarter-wave plates respectively and regulate wave plate angle, operation easier is large.After it finally utilizes grating pair to regulate and control ± and 1 order diffraction light closes bundle again, and this requires that the hologram that this conjunction bundle grating loads with SLM will mate, and limits its dirigibility.Zhao Jian woods group of Northwestern Polytechnical University further improves it and generates light path, propose a kind of vectorial field generation system based on Sagnac interferometer (Generation of arbitrary spatially variant polarization beams with a trapezoid Sagnac interferometer, Optics Express, Vol.20, Issue 19, pp.21715-21721 (2012)): utilize the polarized light that incident light is directly divided into two bundles mutually orthogonal by a polarization beam splitting element in light path, re-shoot to the liquid crystal panel being loaded with holographic grating in advance to obtain required spiral position phase, thus the quarter-wave plate that before solving, in method, slit controls behind light beam polarization not easily regulates and closes the large problem of bundle difficulty.But owing to introducing polarization beam splitting element in light path, add adjustment difficulty, comparatively complicated when particularly this light path switches basic vector.Methods all above only regulates and controls for the polarization characteristic of light field, and to regulate and control mutually for the position of light field be also a ring very important in spatial light field regulation and control, if wish the regulation and control respectively realized for light beam polarization and position phase, very difficult, need the light path of building Spatial transmission in addition, the basic vector switching existed for existing method is inconvenient, stability of layout is poor, cannot realize the shortcomings such as a phase polarization regulates and controls simultaneously, we have invented the hyperchannel space structure light field generating apparatus based on follow-on Michelson interferometer.

Summary of the invention

The purpose of this utility model is, for the deficiency of prior method, proposes and achieves a set of hyperchannel spatial light field generation method based on improved Mechelson interferometer and device.This device has the important feature such as integrated level high (basic vector easy switching), hyperchannel (a polarization regulation and control passage regulates and controls passage mutually with two positions), degree of freedom high (output channel is open light path, can draw in many-sided application).

The utility model is realized by following technical scheme, and a kind of hyperchannel space structure light field generating apparatus based on improved Mechelson interferometer, is replaced by total reflection prism by the catoptron of in Michelson interferometer, makes time light path exchange of two levels.

Further, the another side catoptron in script Michelson interferometer is made only to reflect a level time.

Further, total reflection prism and another side combination get up to make two levels time light path to be separated regulation and control to realize hyperchannel generation light field, can produce a polarization generation passage and regulate and control passage mutually with two positions.

Further, when generating the vectorial field of particular polarization, switching basic vector only needs to insert or remove quarter-wave plate and can realize, convenient and swift.

Further, channel of polarization utilizes and interferes the method for synthesis to obtain vectorial field.

Further, phase passage in position can utilize the principle of holographic optics to obtain the Beams of vortex light field, Bezier light field.

Further, position phase passage by channel of polarization the basic vector of vectorial field of interference synthesis, by realizing the noiseless detection to vectorial field to the detection of two position phase passages.

Further, this device is specially: the light beam of semiconductor laser outgoing becomes the line polarisation of horizontal direction polarization via polaroid, incide in LCD space light modulator, some levels time are gone out by holographic grating diffraction pre-loaded on liquid crystal panel, after beam splitter, the propagation light path of two-beam overlaps completely, choose ± 1 order diffraction is as required basic vector, now ± 1 grade is carried required contrary position phase, the hyperchannel space structure light field generating apparatus spreading into described follow-on Michelson interferometer along parallel direction is become through lens, after the order of diffraction time passes lens, the identical circularly polarized light of two bundle attributes is become through the oblique 45 ° of quarter-wave plates placed of optical axis, afterwards, via beam splitter beam splitting, wherein the light beam of half energy directly selects required ± 1 grade through beam splitter via spatial filter, now utilize a right-angle prism be totally reflected to make to propagate in space ± 1 grade of exchange light path, beam splitter place is got back to along the opposite direction of-1 grade round by+1 grade of meeting that right-angle prism reflects, the light beam of-1 grade is reflexed to the catoptron place of placing top by beam splitter simultaneously, and met by catoptron-1 grade of meeting be reflected back and+1 grade of being totally reflected prismatic reflection, the receiving screen place simultaneously arriving below forms coaxial interference, comprise one piece of 1/2nd wave plate in this light path to be used for the Sense of polarization of+1 grade of rotatory polarization being changed or line polarisation polarization direction being rotated to orthogonal directions, this is Polarization Modulation passage, and now, because catoptron fails+1 grade that is upwards reflected by beam splitter to be reflected back light path,-1 grade that is totally reflected prismatic reflection cannot be met with+1 grade after being reflected downwards by beam splitter, thus now there will be Spatial transmission passage on the right side of Polarization Modulation passage, finally define by ± 1 grade of polarization regulation and control passage of coaxially interfering to be formed and the Spatial transmission passage only having-1 grade of light beam, the receiving screen of below also can change detector C CD into or draw in subsequent optical path by catoptron by obtained light beam, in optical path adjusting process, need the front and back position of minute adjustment catoptron, the light path that the secondary light beam of two levels of interference is mutually passed by is completely the same can realize Polarization Modulation.

Further, the switching of basic vector can be realized by the quarter-wave plate removed in light path, when there being quarter-wave plate in light path, being the rotatory polarization superposition that two bundle sense of rotation are contrary, after removing quarter-wave plate, becoming the line polarisation superposition that two bundle direction of vibration are orthogonal.

The utility model advantage is compared with prior art:

(1) hyperchannel, system has three path channels (two Spatial transmission passages and a Polarization Modulation passage), coordinates LCD space light modulator, achieves any regulation and control for position phase and polarization in a set of light path simultaneously.Separate between the light path of three passages, and light field is interrelated.Can by realizing the noiseless detection to channel of polarization light field for the detection of position phase passage.

(2) integrated level is high, and basic vector easy switching during polarization regulation and control, when adding quarter-wave plate, basic vector is rotatory polarization, removes quarter-wave plate and can be switching to line polarisation basic vector.

Accompanying drawing explanation

Fig. 1 is that the spatial light field based on improved Mechelson interferometer of the present invention generates light path schematic diagram.

Fig. 2 is diffraction ± 1 grade of hologram and generation.Wherein, Fig. 2 (a) is holographic position phasor, and Fig. 2 (b) is the diffraction ± 1 grade hot spot produced.

Non-diffraction weber para-curve (Weber Parabolic) the light field schematic diagram of Fig. 3 for generating in example of the present invention, Fig. 3 (a) is CCD collection image in experiment, and Fig. 3 (b) is theory calculate image.

Embodiment

As shown in Figure 1, the light beam of semiconductor laser 1 outgoing becomes the line polarisation of horizontal direction polarization via polaroid 2, incide in LCD space light modulator 4, being gone out some levels by holographic grating diffraction pre-loaded on liquid crystal panel, time (in light path ,+1 grade of light path is indicated by the solid line,-1 grade of light path is represented by dashed line, in actual light path, after beam splitter, the propagation light path of two-beam overlaps completely, slightly separately to show difference in diagram), we choose ± and 1 order diffraction is as required basic vector, now ± 1 grade of contrary position phase of carrying needed for us, the Michelson interferometer system 3 spreading into improvement along parallel direction is become through lens 5.After the order of diffraction time passes lens 5, the identical circularly polarized light of two bundle attributes is become through the oblique 45 ° of quarter-wave plates placed of optical axis, afterwards, via beam splitter 8 beam splitting, wherein the light beam of half energy directly selects required ± 1 grade through beam splitter via spatial filter 11, now utilize a right-angle prism be totally reflected 12 to make to propagate in space ± 1 grade of exchange light path.Got back to beam splitter 8 place by ﹢ 1 grade of meeting that right-angle prism 12 reflects along the opposite direction of-1 grade round, the light beam of-1 grade is reflexed to catoptron 7 place (catoptron choosing less or additional diaphragm herein makes it be reflected back-1 grade time) of placing top by beam splitter simultaneously.And met by catoptron 7-1 grade of meeting be reflected back and+1 grade of being reflected by prism 12, receiving screen 9 place simultaneously arriving below forms coaxial interference, one piece of 1/2nd wave plate 10 is comprised for being changed by the Sense of polarization of+1 grade of rotatory polarization (or rotating line polarisation polarization direction to orthogonal directions), this is " Polarization Modulation passage " 13 in this light path; And now, because catoptron 7 fails+1 grade that is upwards reflected by beam splitter 8 to be reflected back light path,-1 grade that is reflected by prism 12 cannot be met with+1 grade, thus now there will be " Spatial transmission passage 14 " on the right side of Polarization Modulation passage after by beam splitter 8 downwards reflection; Finally define by ± 1 grade of polarization regulation and control passage 13 of coaxially interfering to be formed and the Spatial transmission passage 14 only having-1 grade of light beam.The receiving screen 9 of below also can change detector C CD into or be drawn in subsequent optical path by obtained light beam by catoptron.In optical path adjusting process, need the front and back position of minute adjustment catoptron 7, the light path that the secondary light beam of two levels of interference is mutually passed by is completely the same can realize Polarization Modulation.Further, can be realized the switching of basic vector by the quarter-wave plate 6 removed in light path, when there being quarter-wave plate in light path, be the rotatory polarization superposition that two bundle sense of rotation are contrary.The line polarisation superposition that two bundle direction of vibration are orthogonal is become after removing quarter-wave plate.

For position phase passage 14, owing to by means of LCD space light modulator, on its liquid crystal panel, the corresponding electrode of each underlying pixel, can control the liquid crystal molecular orientation on each pixel by voltage, thus control the bit phase delay of each pixel.The gray-scale map that we can import 256 GTGs of 8 in a computer carries out the Spatial transmission of 0 ~ 2 π to incident light.For the generation light path of vectorial field, position phase passage gained to light beam be basic vector light needed for channel of polarization.

For channel of polarization 13, interfere the principle of synthesis as follows: the LCD space light modulator in light path loads the phase mehtod figure of the holographic grating needed for us in advance.Now the transmittance function of holographic grating can be write:

t(x,y)＝{1+γcos(2πf ₀x+δ(x,y)]}/2，

Wherein δ is the additional phase brought by holographic grating, and γ is depth of modulation, f ₀for space carrier frequency.The transmittance function of holographic grating can be regulated and controled arbitrarily by Software Coding.After the linearly polarized light of incidence is by LCD space light modulator institute diffraction, the positive and negative one-level produced can become circularly polarized light after quarter-wave plate, wherein+1 grade again through 1/2nd wave plates thus sense of rotation upset, positive and negative one-level now can be expressed as:

$\begin{array}{c}{E}_1=A_0({\hat{e}}_x-{i\hat{e}}_y)\·e^{\mathrm{i\δ}}\\ E_2=A_0({\hat{e}}_x+i{\hat{e}}_y)\·e^{-\mathrm{i\δ}}\end{array}$

A ₀for term amplitude, with for the basic vector under rectangular coordinate system.Positive and negative one-level is coherence stack after channel of polarization closes bundle, can be expressed as:

$E=2A_0(\cos \mathrm{\δ}{\hat{e}}_x+\sin \mathrm{\δ}{\hat{e}}_y)$

Because the form of δ can be chosen arbitrarily, so time can obtain the vectorial field of random polarization state space distribution.

Below in conjunction with accompanying drawing, embodiment of the present utility model is described.

In the utility model based on the index path of the spatial light field generating apparatus of improved Mechelson interferometer as shown in Figure 1.First LCD space light modulator will load the holographic position phasor corresponding to the new spatial light field that generates required for us, when loading can obtain two positive and negative one order diffracted spots in Fig. 2 (b) as Suo Shi Fig. 2 (a) after the phasor of holographic position.Further, for the non-diffracted light of Recent study intrafascicular weber para-curve light beam (Weber Parabolic beam).With the bessel beam (Bessel beam) under cylindrical coordinates, horse smoothing bundle (Mathieu beam) under elliptic coordinates is corresponding, and weber para-curve light beam (Weber Parabolic beam) is the non-diffracted beam under a kind of parabolic coordinates.Paraboloidal coordinate (η, ξ, z) can be converted by rectangular coordinate system (x, y, z) and obtain, and it is defined as follows:

x+iy＝(η+iξ) ²/2,z＝z,

Now the even number of weber para-curve light beam (Weber Parabolic beam) light beam and the horizontal stable state expression formula of odd number can be written as:

$\begin{array}{c}{U}_e(\mathrm{\η},\mathrm{\ξ};a)=\frac{1}{\mathrm{\π}\sqrt{2}}{\left|{\mathrm{\Γ}}_1\right|}^2{P}_e(\mathrm{\σ\ξ};a)P_e(\mathrm{\σ\ξ};-a),\\ U_o(\mathrm{\η},\mathrm{\ξ};a)=\frac{1}{\mathrm{\π}\sqrt{2}}{\left|{\mathrm{\Γ}}_3\right|}^2{P}_o(\mathrm{\σ\ξ};a)P_o(\mathrm{\σ\ξ};-a),\end{array}$

Wherein a is parabola characteristic parameter, $P(v,a)=\underset{n=0}{\overset{\∞}{\mathrm{\Σ}}}{c}_n\frac{v^n}{n!},c_{n+2}={\mathrm{ac}}_n-\frac{n(n-1)c_{n-2}}{4},$

And P _e, P _ocorresponding to the solution under even number and odd number situation, σ=(2k) ^1/2, k is light field momentum, when for even number situation, and c in polynomial expression ₀=1, c ₁=0; When for odd number situation, c ₀=0, c ₁=1.Gamma function in its two formula is respectively Γ ₁=Γ [(1/4)+(1/2) ia], Γ ₃=Γ [(3/4)+(1/2) ia].In experiment, the laser beam after expanding is incident on liquid crystal panel by we, can be considered as plane wave in the areal extent of liquid crystal panel.It is the even number weber para-curve light beam of a=10 that target generates light field, and according to the principle of holographic optics, we can calculate the image now generating required holographic grating, and now phase passage 14 place in place utilizes cameras record beam cross-section pattern, as shown in Figure 3.Experiment gained hot spot is consistent with theory calculate gained hot spot.

The utility model does not elaborate the known technology that part belongs to those skilled in the art.

Claims (9)

1. based on a hyperchannel space structure light field generating apparatus for improved Mechelson interferometer, it is characterized in that: the catoptron of in Michelson interferometer is replaced by total reflection prism, make time light path exchange of two levels.

2. as claimed in claim 1 based on a hyperchannel space structure light field generating apparatus for improved Mechelson interferometer, it is characterized in that: make the another side catoptron (7) in script Michelson interferometer only reflect a level time.

3. the hyperchannel space structure light field generating apparatus based on improved Mechelson interferometer as claimed in claim 1 or 2, it is characterized in that: total reflection prism and another side catoptron (7) combine makes two levels time light path be separated regulation and control to realize hyperchannel generation light field, can produce a polarization generation passage and regulate and control passage mutually with two positions.

4. the hyperchannel space structure light field generating apparatus based on improved Mechelson interferometer as claimed in claim 1 or 2, it is characterized in that: when generating the vectorial field of particular polarization, switch basic vector only to need to insert or remove quarter-wave plate and can realize, convenient and swift.

5. as claimed in claim 1 or 2 based on a hyperchannel space structure light field generating apparatus for improved Mechelson interferometer, it is characterized in that: channel of polarization utilizes interferes the method for synthesis to obtain vectorial field.

6., as claimed in claim 1 or 2 based on a hyperchannel space structure light field generating apparatus for improved Mechelson interferometer, it is characterized in that: position phase passage can utilize the principle of holographic optics to obtain the Beams of vortex light field, Bezier light field.

7. the hyperchannel space structure light field generating apparatus based on improved Mechelson interferometer as claimed in claim 1 or 2, it is characterized in that: position phase passage by channel of polarization the basic vector of vectorial field of interference synthesis, by realizing the noiseless detection to vectorial field to the detection of two position phase passages.

8. the hyperchannel space structure light field generating apparatus based on improved Mechelson interferometer as claimed in claim 1 or 2, it is characterized in that: this device is specially: the light beam of semiconductor laser (1) outgoing becomes the line polarisation of horizontal direction polarization via polaroid (2), incide in LCD space light modulator (4), some levels time are gone out by holographic grating diffraction pre-loaded on liquid crystal panel, after beam splitter, the propagation light path of two-beam overlaps completely, choose ± 1 order diffraction is as required basic vector, now ± 1 grade is carried required contrary position phase, hyperchannel space structure light field generating apparatus (3) spreading into described follow-on Michelson interferometer along parallel direction is become through lens (5), after the order of diffraction time passes lens (5), the identical circularly polarized light of two bundle attributes is become through the oblique 45 ° of quarter-wave plates placed of optical axis, afterwards, via beam splitter (8) beam splitting, wherein the light beam of half energy directly selects required ± 1 grade through beam splitter via spatial filter (11), now utilize a right-angle prism be totally reflected (12) to make to propagate in space ± 1 grade of exchange light path, beam splitter (8) place is got back to along the opposite direction of-1 grade round by+1 grade of meeting that right-angle prism (12) reflects, the light beam of-1 grade is reflexed to catoptron (7) place of placing top by beam splitter simultaneously, and-1 grade of meeting be reflected back by catoptron (7) be totally reflected+1 grade that prism (12) reflects and meet, receiving screen (9) place simultaneously arriving below forms coaxial interference, one piece of 1/2nd wave plate (10) is comprised for being changed by the Sense of polarization of+1 grade of rotatory polarization or rotating line polarisation polarization direction to orthogonal directions in this light path, this is Polarization Modulation passage (13), and now, because catoptron (7) fails+1 grade that is upwards reflected by beam splitter (8) to be reflected back light path, be totally reflected-1 grade that prism (12) reflects to meet with+1 grade after by beam splitter (8) downwards reflection, thus now there will be Spatial transmission passage (14) on the right side of Polarization Modulation passage, finally define by ± 1 grade of polarization regulation and control passage (13) of coaxially interfering to be formed and the Spatial transmission passage (14) only having-1 grade of light beam, the receiving screen (9) of below also can change detector C CD into or draw in subsequent optical path by catoptron by obtained light beam, in optical path adjusting process, need the front and back position of minute adjustment catoptron (7), the light path that the secondary light beam of two levels of interference is mutually passed by is completely the same can realize Polarization Modulation.

9. the hyperchannel space structure light field generating apparatus based on improved Mechelson interferometer as claimed in claim 8, it is characterized in that: the switching that can be realized basic vector by the quarter-wave plate (6) removed in light path, when there being quarter-wave plate in light path, be the rotatory polarization superposition that two bundle sense of rotation are contrary, after removing quarter-wave plate, become the line polarisation superposition that two bundle direction of vibration are orthogonal.