CN102426058B - 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 mutually vertical with the direction of propagation of light, and electric field direction of vibration is called polarization with respect to the asymmetry of optical propagation direction.When light wave reflects in certain medium or on interface, when scattering, transmission and absorption, its emergent light all will show the feature polarization being determined by target self property, and the different conditions of different objects or same object will produce different polarizations.Survey so and obtain this polarization information of object and analyzed, just can obtain the features such as material, pattern, state of object.

Polarization information is surveyed can provide relevant target transmitting that traditional actinometry can not provide and the polarization information of radiant light, and compares with actinometry, and 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: the first is electric light, magneto-optic, photoelastic modulation method.Incident light changes by mechanical rotation or continuous periodic modulation the state (as polarizing angle or phase delay angle etc.) that detects optical element by a series of detection optical element (as 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 is only applicable to steady light beam or gradual continuous radiation light beam, for fast-changing polarization state, cannot carry out real-time detection.The second 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 channel detection, completes the measurement to a certain instantaneous four the Stokes parameters of target simultaneously.This method machinery-free rotates the measuring polarization state that is mainly applicable to light-pulse generator or transition, but in its system, parts too much, complex structure is not compact, is unfavorable for very much the application in space flight, aviation and 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 Savart polariscope of development voluntarily, can obtain spectrum and the image information of target simultaneously, but not obtainable polarization information.

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 simultaneously record target and utilize this static state interference imaging polarimeter to obtain the method for the polarization information of target.

For achieving the above object, the 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 along incident light direction, set gradually, described modulation delayer is comprised of the first delayer and the second delayer; Described polarized interferometer is comprised of the polarizer, Savart polariscope (Savall polariscope) and analyzer; The incident light wherein being sent by target enters modulation delayer after preposition telescopic system collimation, after ovennodulation delayer, become the emergent light that is loaded with modulation intelligence, this emergent light becomes by polarized interferometer the linearly polarized light that the parallel and direction of propagation of two bundles vibrations is parallel to incident light direction again, this linearly polarized light interferes and converges on planar array detector after collecting lens, then machine disposal system is processed shape shadow information, spectral information and the polarization information that obtains target as calculated.

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

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

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

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

Step 1: the Mueller matrix M that is obtained 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, is the phase differential between two-beam in Savart polariscope; Δ is the optical path difference between two-beam in Savart polariscope; σ=1/ λ is wave number, depends on the wavelength response range of spectrometer;

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

S _out＝M _SavartM _ПM _IS _in (2)；

M in formula _i, M _Пand M _savartbe respectively the Mueller matrix of the first delayer, the second delayer and polarized interferometer, establish M=M _savartm _Пm _ifor total Mueller matrix; S _outrepresent the Stokes vector of incident light after ovennodulation delayer; S _inrepresent the Stokes vector of incident light before ovennodulation delayer;

Step 3: by the phase differential of modulation delayer

and the relation between wave number σ is represented by (3) formula:

Wherein

with

represent that respectively light is through the phase-delay quantity of the first delayer, the second delayer, σ=1/ λ is the wavelength response range that wave number depends on spectrometer; Δ n is the refringence between o light and e light in 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 that the component intensity of horizontal direction, vertical direction is poor; C represents that the component intensity of 45 ° of directions of incident light and 135 ° of directions is poor; S represents that the component intensity of incident light clockwise direction and left hand direction is poor; I ' represents total light intensity of emergent light; M ' represents that the component intensity of emergent light horizontal direction, vertical direction is poor; C ' represents that the component intensity of 45 ° of directions of emergent light and 135 ° of directions is poor; S ' represents that the component intensity of emergent light clockwise direction and left hand direction is poor; By formula S _out=M _savartm _Пm _is _inthe intensity spectrum I ' that obtains emergent light is:

Step 5: I ' is carried out to 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 in whole system without any mechanical rotation or movable parts, also the device of controlling without any electric light, acousto-optic or magneto-optic, thus 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, and the lateral shear beam splitting principle of field-compensation type Savart polariscope makes the vertical bar line visual field of whole polarimeter larger simultaneously, and spectral resolution is higher.The 3rd, whole system is simple and compact for structure, it is single shaft light path system altogether, only by the colimated light system of looking in the distance, modulation delayer, polarized interferometer, imaging lens and detector five parts, formed, this is very beneficial for design, processing, experiment and the through engineering approaches of static interference imaging polarimeter, thereby has greatly promoted rapid popularization and the development of polarization information Detection Techniques; The 4th, can realize target shape shadow information, obtain when spectral information and polarization information.

Accompanying drawing explanation

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

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

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 setting gradually along incident light direction.Described modulation delayer 2 is comprised of the first delayer 21 and the second delayer 22.Described polarized interferometer 3 is comprised of the polarizer 31, Savart polariscope 32 and analyzer 33.The incident light wherein being sent by target enters modulation delayer 2 after preposition telescopic system 1 collimation, after ovennodulation delayer 2, become the emergent light that is loaded with modulation intelligence, this emergent light becomes by polarized interferometer 3 linearly polarized light that the parallel and direction of propagation of two bundles vibrations is parallel to incident light direction again, this linearly polarized light interferes and converges on planar array detector 5 after collecting lens 4, then machine disposal system 6 is processed shape shadow information, spectral information and the polarization information that obtains target as calculated.

The thickness proportion of the first delayer 21 and the second delayer 22 is 1: 2.The angle of the quick shaft direction of the quick shaft direction of the first delayer 21 and the second delayer 22 is 45 °.The printing opacity direction of the described polarizer 31 and analyzer 33 is parallel with the quick shaft direction of the 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 is obtained 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, is the optical path difference between two-beam in Savart polariscope; Δ is the optical path difference between two-beam in Savart polariscope; σ=1/ λ is wave number, depends on the wavelength response range of spectrometer.

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

S _out＝M _SavartM _ПM _IS _in (2)；

M in formula _i, M _Пand M _savartbe respectively the Mueller matrix of the first delayer, the second delayer and polarized interferometer, establish M=M _savartm _Пm ₁for total Mueller matrix; S _outrepresent the Stokes vector of incident light after ovennodulation delayer; S _inrepresent the Stokes vector of incident light before ovennodulation delayer.

Step 3: by the phase differential of modulation delayer

and the relation between wave number σ is represented by (3) formula:

Wherein

with

represent that respectively light is through the phase-delay quantity of the first delayer, the second delayer, σ=1/ λ is the wavelength response range that wave number depends on spectrometer; Δ n is the refringence between o light and e light in 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 that the component intensity of incident light horizontal direction, vertical direction is poor; C represents that the component intensity of 45 ° of directions of incident light and 135 ° of directions is poor; S represents that the component intensity of incident light clockwise direction and left hand direction is poor; I ' represents total light intensity of emergent light; M ' represents that the component intensity of emergent light horizontal direction, vertical direction is poor; C ' represents that the component intensity of 45 ° of directions of emergent light and 135 ° of directions is poor; S ' represents that the component intensity of emergent light clockwise direction and left hand direction is 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 different frequency carrier modulation.

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

Claims (3)

1. a 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 along incident light direction, set gradually, described modulation delayer (2) is comprised of the first delayer (21) and the second delayer (22); Described polarized interferometer (3) is comprised of the polarizer (31), Savall polariscope (32) and analyzer (33); Described the first delayer (21) is 1:2 with the thickness proportion of the second delayer (22); The angle of the quick shaft direction of described the first delayer (21) and the quick shaft direction of the second delayer (22) is 45 °

The incident light wherein being sent by target enters modulation delayer (2) after preposition telescopic system (1) collimation, after ovennodulation delayer (2), become the emergent light that is loaded with modulation intelligence, this emergent light becomes by polarized interferometer (3) linearly polarized light that the parallel and direction of propagation of two bundles vibrations is parallel to incident light direction again, it is upper that this linearly polarized light interferes and converge at planar array detector (5) after collecting lens (4), then machine disposal system (6) is processed shape shadow information, spectral information and the polarization information that obtains target as calculated.

2. static interference imaging polarimeter according to claim 1, is characterized in that: the printing opacity direction of the described polarizer (31) and analyzer (33) is parallel with the quick shaft direction of the first delayer (21).

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

Step 1: the Mueller matrix M that is obtained 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, is the phase differential between two-beam in Savart polariscope; Δ is the optical path difference between two-beam in Savart polariscope; σ=1/ λ is 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 _ΠM _ΙS _in （2）；

M in formula _Ι, M _Πand M _savartbe respectively the Mueller matrix of the first delayer, the second delayer and polarized interferometer, establish M=M _savartm _Πm _Ιfor total Mueller matrix; S _outrepresent the Stokes vector of incident light after polarized interferometer; S _inrepresent the Stokes vector of incident light before ovennodulation delayer;

Step 3: by the phase differential of modulation delayer

and the relation between wave number σ is represented by (3) formula:

（i=j；i=1,2；j=1,2） (3)；

Wherein

with

represent that respectively light is through the phase-delay quantity of the first delayer, the second delayer, σ=1/ λ is the wavelength response range that wave number depends on spectrometer; Δ n is the refringence between o light and e light in 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 clockwise 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 clockwise direction and left hand direction; By formula S _out=M _savartm _Πm _Ιs _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 different frequency carrier modulation;

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

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