CN102426058A - Static interference imaging polarizer and method for acquiring polarization information of target - Google Patents

Abstract

The invention relates to a static interference imaging polarizer which comprises a front telescope system, a modulation delayer, a polarized interferometer, an optical collecting lens, a planar array detector and a computer processing system which are arranged in the direction of incident light in sequence, wherein the modulation delayer consists of a first delayer and a second delayer, and the polarized interferometer consists of a polarizer, a Savart polariscope and an analyzer. The static interference imaging polarizer has the advantage of detecting imaging information, spectral information and polarization information at the same time.

Description

The method of the polarization information of a kind of static interference imaging polarimeter and acquisition target

Technical field

The invention belongs to optical field, relate to a kind of structure of static interference imaging polarimeter and utilize this static state interference imaging polarimeter to obtain the method for the polarization information of target.

Background technology

In recent decades, along with the develop rapidly of information science and space remote sensing technology, a kind of polarization technology that utilizes that has been born carries out many-sided new method of surveying to target.Light wave is a kind of transverse electromagnetic wave, and its electric vector is vertical each other with the direction of propagation of light, and the electric field direction of vibration promptly is called polarization with respect to the asymmetry of optical propagation direction.When light wave reflects in certain medium or on the interface, when scattering, transmission and absorption, its emergent light all will show the characteristic polarization that is determined by the target self property, the different conditions of different objects or same object will produce different polarizations.Survey and obtain this polarization information of object so and analyze, just can obtain the characteristics such as material, pattern, state of object.

Polarization information is surveyed can provide the relevant target emission that traditional actinometry can not provide and the polarization information of radiant light, and compares with actinometry, and the polarization information detection has higher accuracy, sharpness and contrast.Therefore this technology has just obtained the great attention of countries in the world at the beginning of being born, and the research of its correlation theory and device is the focus that various countries' space technology is competitively studied always.

The polarization information detection method of research comparative maturity has two kinds at present: first kind is electric light, magneto-optic, photoelastic modulation method.Incident light changes the state (like polarizing angle or phase delay angle etc.) of detection optical element through mechanical rotation or continuous periodic modulation through a series of detection optical element (like analyzer and phase delay device etc.); Measure the light intensity value of one group of emergent light; And to make Fourier analysis, and then obtain describing 4 parameters of the Stokes vector of polarization state.This traditional metering system has moving component, is unfavorable for accurate control and measurement, and only is applicable to steady light beam or gradual continuous radiation light beam, can't carry out real-time detection for fast-changing polarization state.Second kind is four detector division of amplitude methods, adopts the mode of wavefront division or division of amplitude, and light source to be measured is divided into some discrete small light sources, carries out passage and surveys, and accomplishes the measurement to a certain instantaneous four the Stokes parameters of target simultaneously.This method does not have machinery and rotates the measuring polarization state that mainly is applicable to light-pulse generator or transition, but parts too much in its system, complex structure is not compact, is unfavorable for very much the application in space flight, aviation and the remote sensing.

K.Oka once proposed a kind of channel spectrum detection method, had the ability of real-time detection spectrum and polarization information, but can not obtain image information.This seminar had once proposed a kind of novel polarization interference imaging spectrometer based on the Savart polariscope of development voluntarily, can obtain the spectrum and the image information of target simultaneously, but the polarization information that can not obtain.

Summary of the invention

The object of the present invention is to provide a kind of static interference imaging polarimeter of shape shadow information, spectral information and the polarization information that can record target simultaneously and utilize this static state interference imaging polarimeter to obtain the method for the polarization information of target.

For achieving the above object; The present invention provides a kind of static interference imaging polarimeter; Comprise the preposition telescopic system, modulation delayer, polarized interferometer, optical collection lens, planar array detector and the computer processing system that set gradually along the incident light direction, said modulation delayer is made up of first delayer and second delayer; Said polarized interferometer is made up of the polarizer, Savart polariscope (Savall polariscope) and analyzer; The incident light that is wherein sent by target gets into the modulation delayer behind preposition telescopic system collimation; Behind the ovennodulation delayer, become the emergent light that is loaded with modulation intelligence; This emergent light becomes the linearly polarized light that the parallel and direction of propagation of two bundle vibrations is parallel to the incident light direction through polarized interferometer again; This linearly polarized light interferes and converges on the planar array detector through behind the collecting lens, handles shape shadow information, spectral information and the polarization information that obtains target through computer processing system again.

Preferably, the thickness proportion of described first delayer and second delayer is 1: 2.

Preferably, the angle of the quick shaft direction of the quick shaft direction of described first delayer and second delayer is 45 °.

Preferably, the printing opacity direction of the said polarizer and analyzer is parallel with the quick shaft direction of first delayer.

The present invention also provides a kind of and obtains the method for the polarization information of target according to above-mentioned static interference imaging polarimeter, carries out according to following steps:

Step 1: the Mueller matrix M that obtains static interference imaging polarimeter by formula (1):

$M=\frac{1}{4}[1+\cos \mathrm{\δ}]\left[\begin{array}{cccc}1& 0& 1& 0\\ 0& 0& 0& 0\\ 1& 0& 1& 0\\ 0& 0& 0& 0\end{array}\right]---\left(1\right);$

Wherein δ=2 π Δ σ are the phase differential between the two-beam in the Savart polariscope; Δ is the optical path difference between the two-beam in the Savart polariscope; σ=1/ λ is a wave number, depends on the wavelength response range of spectrometer;

Step 2: obtain the Stokes vector of incident light before and after the ovennodulation delayer by formula (2):

S _out＝M _SavartM _ПM _IS _in (2)；

M in the formula _I, M _ПAnd M _SavartBe respectively the Mueller matrix of first delayer, second delayer and polarized interferometer, establish M=M _SavartM _ПM _IBe total Mueller matrix; S _OutRepresent the Stokes vector of incident light behind the ovennodulation delayer; S _InRepresent the Stokes vector of incident light before the ovennodulation delayer;

Step 3: will modulate the phase differential

of delayer and the relation between the wave number σ and represent by (3) formula:

Wherein

With

Represent the phase-delay quantity of light through first delayer, second delayer respectively, σ=1/ λ is the wavelength response range that wave number depends on spectrometer; Δ n is the refringence between o light and the e light in the delayer; d _jThickness for delayer;

Step 4: order

$S_{\mathrm{in}}=\left[\begin{array}{c}I\\ M\\ C\\ S\end{array}\right],$ $S_{\mathrm{out}}=\left[\begin{array}{c}{I}^{\′}\\ M^{\′}\\ C^{\′}\\ S^{\′}\end{array}\right]$

Wherein I represents total light intensity of incident light; M represents the component intensity of horizontal direction, vertical direction poor; C represents the component intensity of 45 ° of directions of incident light and 135 ° of directions poor; S represents the component intensity of incident light dextrorotation direction and left hand direction poor; I ' represents total light intensity of emergent light; M ' represents the component intensity of emergent light horizontal direction, vertical direction poor; C ' represents the component intensity of 45 ° of directions of emergent light and 135 ° of directions poor; S ' represents the component intensity of emergent light dextrorotation direction and left hand direction poor; By formula S _Out=M _SavartM _ПM _IS _InThe intensity spectrum I ' that obtains emergent light is:

Step 5: I ' is carried out the Stokes vector that Fourier transform can obtain incident light, thereby obtain the polarization information of target.

The present invention has following beneficial effect:

Static interference imaging polarimeter is compared with existing polarization information detection method; Its maximum advantage is to have no in the total system mechanical rotation or movable parts; Also have no the device of electric light, acousto-optic or magneto-optic control, thereby realized the complete static real-time detection of polarization information.Secondly; Used field-compensation type Savart polarized interferometer; It has also played the effect of analyzer in spectral interference, the lateral shear beam splitting principle of field-compensation type Savart polariscope makes that the vertical bar line visual field of whole polarimeter is bigger simultaneously, and spectral resolution is higher.The 3rd; Total system is simple and compact for structure; It is single shaft light path system altogether; Only be made up of the colimated light system of looking in the distance, modulation delayer, polarized interferometer, imaging mirror and detector five parts, this is very beneficial for design, processing, experiment and the through engineering approaches of static interference imaging polarimeter, thereby has promoted the rapid popularization and the development of polarization information Detection Techniques greatly; The 4th, obtain when can realize target shape shadow information, spectral information and polarization information.

Description of drawings

Fig. 1 is the structural representation of static interference imaging polarimeter;

Fig. 2 is four parameter oscillograms simulating the target incident light Stokes vector that obtains.

Embodiment

Static interference imaging polarimeter according to the invention, it comprises preposition telescopic system 1, modulation delayer 2, polarized interferometer 3, optical collection lens 4, planar array detector 5 and the computer processing system 6 that sets gradually along the incident light direction.Said modulation delayer 2 is made up of first delayer 21 and second delayer 22.Said polarized interferometer 3 is made up of the polarizer 31, Savart polariscope 32 and analyzer 33.The incident light that is wherein sent by target gets into modulation delayer 2 behind preposition telescopic system 1 collimation; Behind ovennodulation delayer 2, become the emergent light that is loaded with modulation intelligence; This emergent light becomes the linearly polarized light that the parallel and direction of propagation of two bundle vibrations is parallel to the incident light direction through polarized interferometer 3 again; This linearly polarized light interferes and converges on the planar array detector 5 through behind the collecting lens 4, handles shape shadow information, spectral information and the polarization information that obtains target through computer processing system 6 again.

The thickness proportion of first delayer 21 and second delayer 22 is 1: 2.The angle of the quick shaft direction of the quick shaft direction of first delayer 21 and second delayer 22 is 45 °.The printing opacity direction of the said polarizer 31 and analyzer 33 is parallel with the quick shaft direction of first delayer 21.

The polarization information that obtains target according to above-mentioned static interference imaging polarimeter carries out according to following steps:

Step 1: the Mueller matrix M that obtains static interference imaging polarimeter by formula (1):

$M=\frac{1}{4}[1+\cos \mathrm{\δ}]\left[\begin{array}{cccc}1& 0& 1& 0\\ 0& 0& 0& 0\\ 1& 0& 1& 0\\ 0& 0& 0& 0\end{array}\right]---\left(1\right);$

Wherein δ=2 π Δ σ are the optical path difference between the two-beam in the Savart polariscope; Δ is the optical path difference between the two-beam in the Savart polariscope; σ=1/ λ is a wave number, depends on the wavelength response range of spectrometer.

Step 2: obtain the Stokes vector of incident light before and after the ovennodulation delayer by formula (2):

S _out＝M _SavartM _ПM _IS _in (2)；

M in the formula _I, M _ПAnd M _SavartBe respectively the Mueller matrix of first delayer, second delayer and polarized interferometer, establish M=M _SavartM _ПM ₁Be total Mueller matrix; S _OutRepresent the Stokes vector of incident light behind the ovennodulation delayer; S _InRepresent the Stokes vector of incident light before the ovennodulation delayer.

Step 3: will modulate the phase differential

of delayer and the relation between the wave number σ and represent by (3) formula:

Wherein

With Represent the phase-delay quantity of light through first delayer, second delayer respectively, σ=1/ λ is the wavelength response range that wave number depends on spectrometer; Δ n is the refringence between o light and the e light in the delayer; d _jThickness for delayer.

Step 4: order

$S_{\mathrm{in}}=\left[\begin{array}{c}I\\ M\\ C\\ S\end{array}\right],$ $S_{\mathrm{out}}=\left[\begin{array}{c}{I}^{\′}\\ M^{\′}\\ C^{\′}\\ S^{\′}\end{array}\right]$

Wherein I represents total light intensity of incident light; M represents the component intensity of incident light horizontal direction, vertical direction poor; C represents the component intensity of 45 ° of directions of incident light and 135 ° of directions poor; S represents the component intensity of incident light dextrorotation direction and left hand direction poor; I ' represents total light intensity of emergent light; M ' represents the component intensity of emergent light horizontal direction, vertical direction poor; C ' represents the component intensity of 45 ° of directions of emergent light and 135 ° of directions poor; S ' represents the component intensity of emergent light dextrorotation direction and left hand direction poor;

By formula S _Out=M _SavartM _ПM _IS _InThe total light intensity I ' that obtains emergent light is:

Wherein total light intensity I ' of emergent light is the linear superposition of incident light Stokes vector element spectrum after the different frequency carrier modulation.

Step 5: I ' is carried out the Stokes vector (please with reference to Fig. 2) that Fourier transform can obtain the target incident light, thereby obtain the polarization information of target.

Claims (5)

1. static interference imaging polarimeter; It is characterized in that: comprise the preposition telescopic system (1), modulation delayer (2), polarized interferometer (3), optical collection lens (4), planar array detector (5) and the computer processing system (6) that set gradually along the incident light direction, said modulation delayer (2) is made up of first delayer (21) and second delayer (22); Said polarized interferometer (3) is made up of the polarizer (31), Savall polariscope (32) and analyzer (33);

The incident light that is wherein sent by target gets into modulation delayer (2) behind preposition telescopic system (1) collimation; Behind ovennodulation delayer (2), become the emergent light that is loaded with modulation intelligence; This emergent light becomes the linearly polarized light that the parallel and direction of propagation of two bundle vibrations is parallel to the incident light direction through polarized interferometer (3) again; Interfere and converge on the planar array detector (5) behind this linearly polarized light process collecting lens (4), handle shape shadow information, spectral information and the polarization information that obtains target through computer processing system (6) again.

2. static interference imaging polarimeter according to claim 1 is characterized in that: described first delayer (21) is 1: 2 with the thickness proportion of second delayer (22).

3. static interference imaging polarimeter according to claim 1 is characterized in that: the angle of the quick shaft direction of the quick shaft direction of described first delayer (21) and second delayer (22) is 45 °.

4. static interference imaging polarimeter according to claim 2 is characterized in that: the printing opacity direction of the said polarizer (31) and analyzer (33) is parallel with the quick shaft direction of first delayer (21).

5. a static interference imaging polarimeter according to claim 1 obtains the method for the polarization information of target, and it is characterized in that: described method is carried out according to following steps:

Step 1: the Mueller matrix M that obtains static interference imaging polarimeter by formula (1):

$M=\frac{1}{4}[1+\cos \mathrm{\δ}]\left[\begin{array}{cccc}1& 0& 1& 0\\ 0& 0& 0& 0\\ 1& 0& 1& 0\\ 0& 0& 0& 0\end{array}\right]---\left(1\right);$

Wherein δ=2 π Δ σ are the phase differential between the two-beam in the Savart polariscope; Δ is the optical path difference between the two-beam in the Savart polariscope; σ=1/ λ is a wave number, depends on the wavelength response range of spectrometer;

Step 2: obtain the Stokes vector of incident light before and after ovennodulation delayer and polarized interferometer by formula (2):

S _out＝M _SavartM _ПM _IS _in (2)；

M in the formula _I, M _ПAnd M _SavartBe respectively the Mueller matrix of first delayer, second delayer and polarized interferometer, establish M=M _SavartM _ПM _IBe total Mueller matrix; S _OutRepresent incident light through the Stokes vector behind the polarized interferometer; S _InRepresent the Stokes vector of incident light before the ovennodulation delayer;

Step 3: will modulate the phase differential

of delayer and the relation between the wave number σ and represent by (3) formula:

Wherein

With

Represent the phase-delay quantity of light through first delayer, second delayer respectively, σ=1/ λ is the wavelength response range that wave number depends on spectrometer; Δ n is the refringence between o light and the e light in the delayer; d _jThickness for delayer;

Step 4: order

$S_{\mathrm{in}}=\left[\begin{array}{c}I\\ M\\ C\\ S\end{array}\right],$ $S_{\mathrm{out}}=\left[\begin{array}{c}{I}^{\′}\\ M^{\′}\\ C^{\′}\\ S^{\′}\end{array}\right]$

Wherein I represents total light intensity of incident light; M represents the intensity difference of horizontal direction, vertical direction; C represents the intensity difference of 45 ° of directions of incident light and 135 ° of directions; S represents the intensity difference of incident light dextrorotation direction and left hand direction; I ' represents total light intensity of emergent light; M ' represents the intensity difference of emergent light horizontal direction, vertical direction; C ' represents the intensity difference of 45 ° of directions of emergent light and 135 ° of directions; S ' represents the intensity difference of emergent light dextrorotation direction and left hand direction; By formula S _Out=M _SavartM _ПM _IS _InThe intensity spectrum I ' that obtains emergent light is:

Wherein intensity spectrum I ' is the linear superposition of incident light Stokes vector element spectrum after the different frequency carrier modulation;

Step 5: I ' is carried out the Stokes vector that Fourier transform can obtain incident light, thereby obtain the polarization information of target.

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