CN106896371A - A kind of atomic low light signals degree of polarization detection system and the detection method based on the system - Google Patents

Abstract

A kind of atomic low light signals degree of polarization detection system and the detection method based on the system, are related to laser radar technique field.The present invention is, in order to solve during existing laser radar detection pole distant object, to obtain information in single, it is impossible to the problem of enough judgement and the identification for effectively carrying out target.A kind of atomic low light signals degree of polarization detection system of the present invention and the detection method based on the system, target is irradiated by the optical signal of Polarization Modulation, and echo-signal light is carried out into four tunnel light splitting and photon counting is carried out with Gm APD.The photon polarization information of echo-signal light is can obtain according to count results, so as to reach the purpose of identification target.The present invention carries out photon counting using Gm APD, and response sensitivity has reached single photon magnitude, breaches the counting bottleneck that conventional radar runs into, and the resolving of the degree of polarization of atomic weak signal is realized according to response count.Detection and the other Feebleness Light Signal Examining of single-photon-level are recognized suitable for distant object.

Description

A kind of atomic low light signals degree of polarization detection system and the detection method based on the system

Technical field

The invention belongs to laser radar technique field, more particularly to extremely remote target acquisition identification technology.

Background technology

For extremely remote target, the echo-signal light of detectable signal light is often extremely faint, has reached single photon Magnitude, common light intensity detector cannot respond to so faint signal, this be also conventional laser radar to remote target acquisition when The bottleneck for being run into.

Current single-photon detecting survey technology can only obtain the three-dimensional distance picture of target, and response sensitivity is restricted, only The judgement and identification of target are carried out by the Range Profile of target, information is excessively single, tends not to effectively obtain target polarization Information, enters the judgement and identification for being unable to effectively carry out target.

The content of the invention

The present invention is, in order to solve during existing laser radar detection pole distant object, to obtain information in single, it is impossible to enough The problem of effective judgement and the identification for carrying out target, now provides a kind of atomic low light signals degree of polarization detection system and based on this The detection method of system.

A kind of atomic low light signals degree of polarization detection system, including：Emission part and acceptance division；

Emission part includes：Pulse laser 110, the emission part polarizer 120, emission part quarter wave plate 130, transmitting optical system System 140 and pseudorandomcode controller 150,

The coded sequence letter of the coded sequence signal output end connection pulse laser 110 of pseudorandomcode controller 150 Number input, the pulse laser that pulse laser 110 sends sequentially passes through the emission part polarizer 120 and emission part quarter wave plate 130 It is transmitted through optical transmitting system 140, optical transmitting system 140 carries out collimator and extender to incident light and outgoing is to target to be detected；

Acceptance division includes：222, No. three optical splitters 223 of the optical splitter of optical splitter 221, two of receiving optics 210, Acceptance division quarter wave plate 230, number polarizer 241 of acceptance division, No. two polarizers 242 of acceptance division, No. three polarizers 243 of acceptance division, Number 253, No. four single-photon detectors of single-photon detector of single-photon detector 252, three of single-photon detector 251, two 254th, symbol converter 270 and synchronizing signal processing system 260,

Receiving optics 210 is used to focusing on and gathering the flashlight that detection target is returned, and receiving optics 210 goes out It is a transmitted light and a reflected light that light is penetrated through the beam splitting of an optical splitter 221, and a transmitted light is through the beam splitting of No. two optical splitters 222 It is No. two transmitted lights and No. two reflected lights, a reflected light is No. three transmitted lights and No. three reflections through the beam splitting of No. three optical splitters 223 Light, No. two reflected lights sequentially pass through number polarizer 241 of acceptance division quarter wave plate 230 and acceptance division and are transmitted through No. two single-photon detectings Survey on the photosurface of device 252, No. two transmitted lights are transmitted through No. three single-photon detectors 253 by No. three polarizers 243 of acceptance division Photosurface on, No. three transmitted lights are incident on a photosurface for single-photon detector 251, and No. three reflected lights are by acceptance division No. two polarizers 242 are transmitted through on No. four photosurfaces of single-photon detector 254, the synchronous acquisition of synchronizing signal processing system 260 A number single-photon detector 253 of single-photon detector 252, three of single-photon detector 251, two and No. four single-photon detectors The signal of 254 outputs,

The coded sequence letter of the coded sequence signal output end connection symbol converter 270 of pseudorandomcode controller 150 Number input, the encoded signal input of the encoded signal output end connection synchronizing signal processing system 260 of symbol converter 270 End,

Synchronizing signal processing system 260 is processed to obtain the polarization of echo-signal light to four road signals of synchronous acquisition Degree.

Detection method based on above-mentioned detection system comprises the following steps：

Flashlight debugging step：

Open pulse laser 110 so that a list of single-photon detector 252, three of single-photon detector 251, two Photon detector 253 and No. four single-photon detectors 254 can receive echo-signal light；

Stokes parameter setting procedure：

If the stokes parameter of the echo-signal light of the collection of receiving optics 210 is：

(S₀ S₁ S₂ S₃)^T

Wherein, S₀、S₁、S₂、S₃It is respectively four parameters of normalized stokes parameter,

Because echo-signal light is divided into four tunnels by 221, No. two optical splitters 222 of an optical splitter and No. three optical splitters 223, if The overall strength of echo letter light number is I₀, then it is per the strength S tokes of echo-signal light stokes parameter all the way：

The corresponding light intensity of detector obtains step：

The stokes parameter Stokes1 of No. four single-photon detectors 254 is：

Wherein,It is 90 ° of acting matrixes of the analyzer of placement, and

Then single-photon detector 254 responds light intensity I_s(1) it is：

Above formula is expressed as the form N of photoelectron number_s(1), as：

Wherein h is planck constant, and υ is the frequency of light

The stokes parameter Stokes2 of No. three single-photon detectors 253 is：

Then No. three single-photon detectors 253 respond light intensity I_s(2) it is：

Above formula is expressed as the form N of photoelectron number_s(2), as：

The stokes parameter Stokes3 of No. two single-photon detectors 252 is：

Then No. two single-photon detectors 252 respond light intensity I_s(3) it is：

Above formula is expressed as the form N of photoelectron number_s(3), as：

The stokes parameter Stokes1 of a number single-photon detector 251 is：

Then a single-photon detector 251 responds light intensity I_s(4) it is：

Above formula is expressed as the form N of photoelectron number_s(4), as：

Polarization degree information obtains step：

Derivation simultaneous according to four road signals can obtain the relation of stokes parameter and four detector signal intensity, That is stokes parameter solution formula：

If the pulse number of the transmitting of pulse laser 110 is M, in four single-photon detectors to the intensity of atomic dim light When measuring, the snowslide umber of pulse of the i-th road signal is K (i), i=1,2,3,4, then detection probability P (i) be：

The photoelectron sum for being then incident to four single-photon detectors is respectively：

According to four countings of single-photon detector, the light intensity of the photoelectron number form on each road is calculated respectively, bring Si Tuo into Gram this parameter solution formula, and by normalized, it becomes possible to obtain the stokes parameter (S of echo-signal light₀ S₁ S₂ S₃)^T, then formula according to degree of polarization obtain the polarization degree information P of target：

A kind of atomic low light signals degree of polarization detection system of the present invention and the detection method based on the system, by The optical signal irradiation target of Polarization Modulation, carries out echo-signal light four tunnel light splitting and is carried out with Gm-APD (single-photon detector) Photon counting.The photon polarization information of echo-signal light is can obtain according to count results, so as to reach the purpose of identification target.This Invention carries out photon counting using Gm-APD, and response sensitivity has reached single photon magnitude, breaches what conventional radar ran into Bottleneck is counted, and the resolving of the degree of polarization of atomic weak signal is realized according to response count.

The beneficial effects of the invention are as follows：

(1) response sensitivity reaches single photon magnitude, breaches the response sensitivity that conventional radar runs under weak signal Bottleneck；

(2) single photon rank small-signal polarization information acquisition methods are given.

The present invention is applied to distant object and recognizes detection and the other Feebleness Light Signal Examining of single-photon-level.

Brief description of the drawings

Fig. 1 is the structural representation of a kind of atomic low light signals degree of polarization detection system described in specific embodiment one.

Specific embodiment

Specific embodiment one：Reference picture 1 illustrates present embodiment, a kind of atomic dim light described in present embodiment Signal degree of polarization detection system, including：Emission part and acceptance division；

Emission part includes：Pulse laser 110, the emission part polarizer 120, emission part quarter wave plate 130, transmitting optical system System 140 and pseudorandomcode controller 150,

The coded sequence letter of the coded sequence signal output end connection pulse laser 110 of pseudorandomcode controller 150 Number input, the pulse laser that pulse laser 110 sends sequentially passes through the emission part polarizer 120 and emission part quarter wave plate 130 It is transmitted through optical transmitting system 140, optical transmitting system 140 carries out collimator and extender to incident light and outgoing is to target to be detected；

Acceptance division includes：222, No. three optical splitters 223 of the optical splitter of optical splitter 221, two of receiving optics 210, Acceptance division quarter wave plate 230, number polarizer 241 of acceptance division, No. two polarizers 242 of acceptance division, No. three polarizers 243 of acceptance division, Number 253, No. four single-photon detectors of single-photon detector of single-photon detector 252, three of single-photon detector 251, two 254th, symbol converter 270 and synchronizing signal processing system 260,

Receiving optics 210 is used to focusing on and gathering the flashlight that detection target is returned, and receiving optics 210 goes out It is a transmitted light and a reflected light that light is penetrated through the beam splitting of an optical splitter 221, and a transmitted light is through the beam splitting of No. two optical splitters 222 It is No. two transmitted lights and No. two reflected lights, a reflected light is No. three transmitted lights and No. three reflections through the beam splitting of No. three optical splitters 223 Light, No. two reflected lights sequentially pass through number polarizer 241 of acceptance division quarter wave plate 230 and acceptance division and are transmitted through No. two single-photon detectings Survey on the photosurface of device 252, No. two transmitted lights are transmitted through No. three single-photon detectors 253 by No. three polarizers 243 of acceptance division Photosurface on, No. three transmitted lights are incident on a photosurface for single-photon detector 251, and No. three reflected lights are by acceptance division No. two polarizers 242 are transmitted through on No. four photosurfaces of single-photon detector 254, the synchronous acquisition of synchronizing signal processing system 260 A number single-photon detector 253 of single-photon detector 252, three of single-photon detector 251, two and No. four single-photon detectors The signal of 254 outputs；

The coded sequence letter of the coded sequence signal output end connection symbol converter 270 of pseudorandomcode controller 150 Number input, the encoded signal input of the encoded signal output end connection synchronizing signal processing system 260 of symbol converter 270 End,

Synchronizing signal processing system 260 is processed to obtain the polarization of echo-signal light to four road signals of synchronous acquisition Degree.

In emission part, the emitted portion's polarizer 120 of pulse laser that pulse laser 110 sends obtains complete line after transmiting Polarised light, the complete emitted portion's quarter wave plate 130 of linearly polarized light is incident to optical transmitting system 140 after carrying out Polarization Modulation, transmitting Optical system 140 carries out collimator and extender to incident light and exposes to target to be detected；Pseudorandomcode controller produce first with 0/1 coded sequence of machine, wherein the ratio shared by 0 and 1 code element is impartial, all it is 50%, but position is random.1 is exactly One high level can control laser to produce pulse, and 0 is a low level room, and at this moment laser does not launch pulse, this Sample laser pulse just carries out regulation and control and launches by pseudorandomcode.

In acceptance division, echo-signal light is carried out into four tunnel light splitting, respectively by different optical elements, finally counted by Gm-APD Number, by substantial amounts of statistics, the degree of polarization of echo-signal light can be resolved according to 4 response counts of Gm-APD.Using Gm- APD carries out photon counting to echo-signal light, and response sensitivity reaches photon magnitude.

The important innovation of present embodiment is to devise pseudorandomcode control system, pseudorandomcode control all the way Laser processed produces laser signal, and another road by 1 original reservation, and the code element of corresponding room 0 is turned by symbol converter Change -1 into, the big of the code element is less than 1 equal, symbol contrast.Sequence of symhols after so changing is waited for and four detections The echo-signal of device carries out coherent detection, and that relevant peaks add up is exactly the situation N of the photoelectron counting of correspondence detector_s(1), N_s(2),N_s(3),N_s(4).Benefit is that the influence of noise can be removed in the case of small-signal, because noise is random appearance , and 1 symbol probability with -1 is equal, therefore noise to appear in 1 element position equal with the probability of -1 element position, pass through Symbol equal in magnitude is opposite to be added up, and the average value of noise just can be 0, effectively eliminate the influence of noise, effectively Improve the detectivity of the atomic low light signals degree of polarization detection system of present embodiment.

Specific embodiment two：Present embodiment is to a kind of atomic low light signals polarization described in specific embodiment one Degree detection system is described further, and in present embodiment, No. two polarizing angles of the polarizer 242 of acceptance division are 90 °, acceptance division one The polarizing angle of number No. three polarizers 243 of the polarizer 241 and acceptance division is 45 °, and the azimuth of acceptance division quarter wave plate 230 is 0 °.

Specific embodiment three：Present embodiment is to a kind of atomic low light signals polarization described in specific embodiment two Degree detection system is described further, and in present embodiment, synchronizing signal processing system 260 is included with lower unit：

Stokes parameter setup unit：

If the stokes parameter of the echo-signal light of the collection of receiving optics 210 is：

(S₀ S₁ S₂ S₃)^T

Wherein, S₀、S₁、S₂、S₃It is respectively four parameters of normalized stokes parameter,

Because echo-signal light is divided into four tunnels by 221, No. two optical splitters 222 of an optical splitter and No. three optical splitters 223, if The overall strength of echo letter light number is I₀, then it is per the strength S tokes of echo-signal light stokes parameter all the way：

The corresponding light intensity obtaining unit of detector：

The stokes parameter Stokes1 of No. four single-photon detectors 254 is：

Wherein,It is 90 ° of acting matrixes of the analyzer of placement, and

Then single-photon detector 254 responds light intensity I_s(1) it is：

Above formula is expressed as the form N of photoelectron number_s(1), as：

Wherein h is planck constant, and υ is the frequency of light

The stokes parameter Stokes2 of No. three single-photon detectors 253 is：

Wherein,It is 45 ° of acting matrixes of the analyzer of placement, and：

Then No. three single-photon detectors 253 respond light intensity I_s(2) it is：

Above formula is expressed as the form N of photoelectron number_s(2), as：

The stokes parameter Stokes3 of No. two single-photon detectors 252 is：

Wherein, M_1/4(0 °) is 0 ° of acting matrix of the quarter wave plate of placement, and：

Then No. two single-photon detectors 252 respond light intensity I_s(3) it is：

Above formula is expressed as the form N of photoelectron number_s(3), as：

The stokes parameter Stokes1 of a number single-photon detector 251 is：

Then a single-photon detector 251 responds light intensity I_s(4) it is：

Above formula is expressed as the form N of photoelectron number_s(4), as：

Polarization degree information obtaining unit：

Derivation simultaneous according to four road signals can obtain the relation of stokes parameter and four detector signal intensity, That is stokes parameter solution formula：

In actual applications, one-shot measurement is the 2M signal pulse sequence of code element using one group long degree, due to initial 1 and 0 (have the probability of no pulse equal) is set, therefore the pulse number of transmitting should be M.In four single-photon detectors When intensity to atomic dim light is measured, the result of counting carries out ASSOCIATE STATISTICS with 1 and -1 sequence after code element conversion respectively, So counting of noise can just be removed, remaining relevant peaks are corresponding be exactly signal (the snowslide pulse of signal of counting situation Number), it is K (i), wherein i represents several signals, i=1,2,3,4.

It is K (i) in the snowslide umber of pulse of the i-th road signal, then detection probability P (i) is：

The photoelectron sum for being then incident to four single-photon detectors is respectively：

According to four countings of single-photon detector, the light intensity of the photoelectron number form on each road is calculated respectively, bring Si Tuo into Gram this parameter solution formula, and by normalized, it becomes possible to obtain the stokes parameter (S of echo-signal light₀ S₁ S₂ S₃)^T, then formula according to degree of polarization obtain the polarization degree information P of target：

Specific embodiment four：Present embodiment is to a kind of atomic low light signals polarization described in specific embodiment three Degree detection system is described further, and in four road photon stokes parameter detection light paths, the optical element for being used is not Completely preferably, in test result of detection is larger with the deviation of actual value, i.e., echo-signal light enters into the Si Tuo of receiver Gram this parameter S_inWith the stokes parameter S for eventually passing through reception system arrival detector_outIt is not fully equal, and it is non-ideal Pilot system can regard a matrix N as, that is, have relation S_in=N*S_outIf instrument matrix N can be found by experiment, according to Detecting the combination of stokes parameter containing the error above formula for obtaining counter can still release the Stokes for just inciding receiver Parameter (i.e. the stokes parameter of echo-signal light, does not influence by reception system),

Therefore, the acquisition system that stokes parameter is given in present embodiment includes：

Parameter setup unit：

If actual signal light stokes parameter is (S₀',S₁',S₂',S₃')^T,

The stokes parameter that detection is obtained is (S₀,S₁,S₂,S₃)^T,

Nonideal instrument matrix

Then there is relational expression：

Above-mentioned relation formula is launched to obtain：

Instrument matrix N obtaining unit：

N regulation is carried out to the emission part polarizer 120 and emission part quarter wave plate 130 so that each single-photon detector is obtained N kinds detect light, the equation set up between n stokes parameter and instrument matrix element：

S₀'¹=m₁₁S₀ ¹+m₁₂S₁ ¹+m₁₃S₂ ¹+m₁₄S₃ ¹

S₁'¹=m₂₁S₀ ¹+m₂₂S₁ ¹+m₂₃S₂ ¹+m₂₄S₃ ¹

S₂'¹=m₃₁S₀ ¹+m₃₂S₁ ¹+m₃₃S₂ ¹+m₃₄S₃ ¹

S₃'¹=m₄₁S₀ ¹+m₄₂S₁ ¹+m₄₃S₂ ¹+m₄₄S₃ ¹

S₀'²=m₁₁S₀ ²+m₁₂S₁ ²+m₁₃S₂ ²+m₁₄S₃ ²

S₁'²=m₂₁S₀ ²+m₂₂S₁ ²+m₂₃S₂ ²+m₂₄S₃ ²

S₃'ⁿ=m₄₁S₀ ⁿ+m₄₂S₁ ⁿ+m₄₃S₂ ⁿ+m₄₄S₃ ⁿ

One least square solution is given to above equation, and then near the instrument matrix N of actual value；

Stokes parameter obtaining unit：

The stokes parameter for being incident to each single-photon detector is instead released using above-mentioned instrument matrix N.

Present embodiment has 16 unknown quantitys, and 4 equations can be set up in one-shot measurement, and four need to be only measured in theory It is secondary completely to determine instrument matrix.But the crystalline axis direction of shaken thoroughly due to polarizer direction and wave plate point to be not it is perfect, Number of photons rises and falls also under low light condition can produce large effect to result of detection.Other Metzler matrix is probably singular matrix, side Journey group may be without solution.Therefore need repeatedly to adjust the sensing of polarizer and wave plate, the light of various different polarization states is produced, through detection, The equation set up between multiple stokes parameters and instrument matrix element.

Specific embodiment five：Described in present embodiment based on a kind of spy of atomic low light signals degree of polarization detection system Survey method, the system includes：Emission part and acceptance division；

Emission part includes：Pulse laser 110, the emission part polarizer 120, emission part quarter wave plate 130, transmitting optical system System 140 and pseudorandomcode controller 150,

The coded sequence letter of the coded sequence signal output end connection pulse laser 110 of pseudorandomcode controller 150 Number input, the pulse laser that pulse laser 110 sends sequentially passes through the emission part polarizer 120 and emission part quarter wave plate 130 It is transmitted through optical transmitting system 140, optical transmitting system 140 carries out collimator and extender to incident light and outgoing is to target to be detected；

Acceptance division includes：222, No. three optical splitters 223 of the optical splitter of optical splitter 221, two of receiving optics 210, Acceptance division quarter wave plate 230, number polarizer 241 of acceptance division, No. two polarizers 242 of acceptance division, No. three polarizers 243 of acceptance division, Number 253, No. four single-photon detectors of single-photon detector of single-photon detector 252, three of single-photon detector 251, two 254 and symbol converter 270,

Receiving optics 210 is used to focusing on and gathering the flashlight that detection target is returned, and receiving optics 210 goes out It is a transmitted light and a reflected light that light is penetrated through the beam splitting of an optical splitter 221, and a transmitted light is through the beam splitting of No. two optical splitters 222 It is No. two transmitted lights and No. two reflected lights, a reflected light is No. three transmitted lights and No. three reflections through the beam splitting of No. three optical splitters 223 Light, No. two reflected lights sequentially pass through number polarizer 241 of acceptance division quarter wave plate 230 and acceptance division and are transmitted through No. two single-photon detectings Survey on the photosurface of device 252, No. two transmitted lights are transmitted through No. three single-photon detectors 253 by No. three polarizers 243 of acceptance division Photosurface on, No. three transmitted lights are incident on a photosurface for single-photon detector 251, and No. three reflected lights are by acceptance division No. two polarizers 242 are transmitted through on No. four photosurfaces of single-photon detector 254, the code sequence of pseudorandomcode controller 150 Column signal output end connects the coded sequence signal input of symbol converter 270；

Methods described comprises the following steps：

Flashlight debugging step：

Open pulse laser 110 so that a list of single-photon detector 252, three of single-photon detector 251, two Photon detector 253 and No. four single-photon detectors 254 can receive echo-signal light；

Stokes parameter setting procedure：

If the stokes parameter of the echo-signal light of the collection of receiving optics 210 is：

(S₀ S₁ S₂ S₃)^T

Wherein, S₀、S₁、S₂、S₃It is respectively four parameters of normalized stokes parameter,

Because echo-signal light is divided into four tunnels by 221, No. two optical splitters 222 of an optical splitter and No. three optical splitters 223, if The overall strength of echo letter light number is I₀, then it is per the strength S tokes of echo-signal light stokes parameter all the way：

The corresponding light intensity of detector obtains step：

The stokes parameter Stokes1 of No. four single-photon detectors 254 is：

Wherein,It is 90 ° of acting matrixes of the analyzer of placement, and

Then single-photon detector 254 responds light intensity I_s(1) it is：

Above formula is expressed as the form N of photoelectron number_s(1), as：

Wherein h is planck constant, and υ is the frequency of light

The stokes parameter Stokes2 of No. three single-photon detectors 253 is：

Then No. three single-photon detectors 253 respond light intensity I_s(2) it is：

Above formula is expressed as the form N of photoelectron number_s(2), as：

The stokes parameter Stokes3 of No. two single-photon detectors 252 is：

Then No. two single-photon detectors 252 respond light intensity I_s(3) it is：

Above formula is expressed as the form N of photoelectron number_s(3), as：

The stokes parameter Stokes1 of a number single-photon detector 251 is：

Then a single-photon detector 251 responds light intensity I_s(4) it is：

Above formula is expressed as the form N of photoelectron number_s(4), as：

Polarization degree information obtains step：

Derivation simultaneous according to four road signals can obtain the relation of stokes parameter and four detector signal intensity, That is stokes parameter solution formula：

If the pulse number of pulse laser (110) transmitting is M, in four single-photon detectors to the strong of atomic dim light Degree is when measuring, and the snowslide umber of pulse of the i-th road signal is K (i), i=1,2,3,4, then detection probability P (i) be：

The photoelectron sum for being then incident to four single-photon detectors is respectively：

According to four countings of single-photon detector, the light intensity of the photoelectron number form on each road is calculated respectively, bring Si Tuo into Gram this parameter solution formula, and by normalized, it becomes possible to obtain the stokes parameter (S of echo-signal light₀ S₁ S₂ S₃)^T, then formula according to degree of polarization obtain the polarization degree information P of target：

Specific embodiment six：Present embodiment be to described in specific embodiment five based on a kind of atomic low light signals The detection method of degree of polarization detection system is described further, and the preparation method of stokes parameter is comprised the following steps：

Parameter setting procedure：

If actual signal light stokes parameter is (S₀',S₁',S₂',S₃')^T,

The stokes parameter that detection is obtained is (S₀,S₁,S₂,S₃)^T,

Nonideal instrument matrix

Then there is relational expression：

Above-mentioned relation formula is launched to obtain：

Instrument matrix N obtains step：

N regulation is carried out to the emission part polarizer 120 and emission part quarter wave plate 130 so that each single-photon detector is obtained N kinds detect light, the equation set up between n stokes parameter and instrument matrix element：

S₀'¹=m₁₁S₀ ¹+m₁₂S₁ ¹+m₁₃S₂ ¹+m₁₄S₃ ¹

S₁'¹=m₂₁S₀ ¹+m₂₂S₁ ¹+m₂₃S₂ ¹+m₂₄S₃ ¹

S₂'¹=m₃₁S₀ ¹+m₃₂S₁ ¹+m₃₃S₂ ¹+m₃₄S₃ ¹

S₃'¹=m₄₁S₀ ¹+m₄₂S₁ ¹+m₄₃S₂ ¹+m₄₄S₃ ¹

S₀'²=m₁₁S₀ ²+m₁₂S₁ ²+m₁₃S₂ ²+m₁₄S₃ ²

S₁'²=m₂₁S₀ ²+m₂₂S₁ ²+m₂₃S₂ ²+m₂₄S₃ ²

S₃'ⁿ=m₄₁S₀ ⁿ+m₄₂S₁ ⁿ+m₄₃S₂ ⁿ+m₄₄S₃ ⁿ

One least square solution is given to above equation, and then near the instrument matrix N of actual value；

Stokes parameter obtains step：

The stokes parameter for being incident to each single-photon detector is instead released using above-mentioned instrument matrix N.

Claims (6)

1. a kind of atomic low light signals degree of polarization detection system, it is characterised in that including：Emission part and acceptance division；

Emission part includes：Pulse laser (110), the emission part polarizer (120), emission part quarter wave plate (130), transmitting optics System (140) and pseudorandomcode controller (150),

The coded sequence letter of coded sequence signal output end connection pulse laser (110) of pseudorandomcode controller (150) Number input, the pulse laser that pulse laser (110) sends sequentially passes through the emission part polarizer (120) and the ripple of emission part 1/4 Piece (130) is transmitted through optical transmitting system (140), optical transmitting system (140) collimator and extender is carried out to incident light and outgoing extremely Target to be detected；

Acceptance division includes：Receiving optics (210), optical splitter (221), No. two optical splitters (222), No. three optical splitters (223), acceptance division quarter wave plate (230), number polarizer (241) of acceptance division, acceptance division No. two polarizers (242), acceptance divisions three Number polarizer (243), single-photon detector (251), No. two single-photon detectors (252), No. three single-photon detectors (253), No. four single-photon detectors (254), symbol converter (270) and synchronizing signal processing systems (260),

Receiving optics (210) is for focusing on and gathers the flashlight that detection target is returned, and receiving optics (210) go out It is a transmitted light and a reflected light that light is penetrated through the beam splitting of an optical splitter (221), and a transmitted light is through No. two optical splitters (222) Beam splitting is No. two transmitted lights and No. two reflected lights, and a reflected light is No. three transmitted lights and three through the beam splitting of No. three optical splitters (223) Number reflected light, No. two reflected lights sequentially pass through number polarizer (241) of acceptance division quarter wave plate (230) and acceptance division and are transmitted through two On the photosurface of number single-photon detector (252), No. two transmitted lights are transmitted through No. three lists by No. three polarizers (243) of acceptance division On the photosurface of photon detector (253), No. three transmitted lights are incident on a photosurface for single-photon detector (251), and three Number reflected light is transmitted through on No. four photosurfaces of single-photon detector (254) by No. two polarizers (242) of acceptance division, synchronous letter Number number single-photon detector (251) of processing system (260) synchronous acquisition, No. two single-photon detectors (252), No. three single photons Detector (253) and No. four signals of single-photon detector (254) output,

The coded sequence letter of coded sequence signal output end connection symbol converter (270) of pseudorandomcode controller (150) Number input, the encoded signal of encoded signal output end connection synchronizing signal processing system (260) of symbol converter (270) is defeated Enter end,

Synchronizing signal processing system (260) is processed to obtain the polarization of echo-signal light to four road signals of synchronous acquisition Degree.

2. a kind of atomic low light signals degree of polarization detection system according to claim 1, it is characterised in that acceptance division two The polarizing angle of the polarizer (242) is 90 °, No. three polarizing angles of the polarizer (243) of number polarizer (241) of acceptance division and acceptance division 45 ° are, the azimuth of acceptance division quarter wave plate (230) is 0 °.

3. a kind of atomic low light signals degree of polarization detection system according to claim 2, it is characterised in that at synchronizing signal Reason system (260) is including with lower unit：

Stokes parameter setup unit：

If the stokes parameter of the echo-signal light of receiving optics (210) collection is：

(S₀ S₁ S₂ S₃)^T

Wherein, S₀、S₁、S₂、S₃It is respectively four parameters of normalized stokes parameter,

Because echo-signal light is divided into four tunnels by an optical splitter (221), No. two optical splitters (222) and No. three optical splitters (223), If the overall strength of echo letter light number is I₀, then it is per the strength S tokes of echo-signal light stokes parameter all the way：

$Stokes=\frac{I_0}{4}\left(\begin{array}{c}{S}_0\\ S_1\\ S_2\\ S_3\end{array}\right);$

The corresponding light intensity obtaining unit of detector：

The stokes parameter Stokes1 of No. four single-photon detectors (254) is：

Wherein,It is 90 ° of acting matrixes of the analyzer of placement,

Then single-photon detector (254) responds light intensity I_s(1) it is：

$I_s\left(1\right)=\frac{I_0}{8}(S_0-S_1),$

Above formula is expressed as the form N of photoelectron number_s(1), as：

$N_s\left(1\right)=\frac{I_s\left(1\right)}{h\mathrm{\υ}}=\frac{I_0}{8h\mathrm{\υ}}(S_0-S_1);$

Wherein h is planck constant, and υ is the frequency of light

The stokes parameter Stokes2 of No. three single-photon detectors (253) is：

Wherein,It is 45 ° of acting matrixes of the analyzer of placement,

Then No. three single-photon detectors (253) respond light intensity I_s(2) it is：

$I_s\left(2\right)=\frac{1}{8}(S_0+S_2),$

Above formula is expressed as the form N of photoelectron number_s(2), as：

$N_s\left(2\right)=\frac{I_s\left(2\right)}{h\mathrm{\υ}}=\frac{I_0}{8h\mathrm{\υ}}(S_0+S_2);$

The stokes parameter Stokes3 of No. two single-photon detectors (252) is：

Wherein, M_1/4(0 °) is 0 ° of acting matrix of the quarter wave plate of placement,

Then No. two single-photon detectors (252) respond light intensity I_s(3) it is：

$I_s\left(3\right)=\frac{1}{8}(S_0-S_3),$

Above formula is expressed as the form N of photoelectron number_s(3), as：

$N_s\left(3\right)=\frac{I_s\left(3\right)}{h\mathrm{\υ}}=\frac{I_0}{8h\mathrm{\υ}}(S_0-S_3);$

The stokes parameter Stokes1 of a number single-photon detector (251) is：

$Stokes1=Stokes=\frac{I_0}{4}\left(\begin{array}{c}{S}_0\\ S_1\\ S_2\\ S_3\end{array}\right),$

Then a single-photon detector (251) responds light intensity I_s(4) it is：

$I_s\left(4\right)=\frac{I_0}{4}{S}_0,$

Above formula is expressed as the form N of photoelectron number_s(4), as：

$N_s\left(4\right)=\frac{I_s\left(4\right)}{h\mathrm{\υ}}=\frac{I_0}{4h\mathrm{\υ}}{S}_0;$

Polarization degree information obtaining unit：

Derivation simultaneous according to four road signals can obtain the relation of stokes parameter and four detector signal intensity, i.e., this Lentor parameter solution formula：

$\left(\begin{array}{c}{S}_0\\ S_1\\ S_2\\ S_3\end{array}\right)=\frac{4h\mathrm{\υ}}{I_0}\left(\begin{array}{c}{N}_s\left(4\right)\\ N_s\left(4\right)-2N_s\left(1\right)\\ 2N_s\left(2\right)-N_s\left(4\right)\\ N_s\left(4\right)-2N_s\left(3\right)\end{array}\right)$

If the pulse number of pulse laser (110) transmitting is M, the intensity of atomic dim light is entered in four single-photon detectors During row measurement, the snowslide umber of pulse of the i-th road signal is K (i), i=1,2,3,4, then detection probability P (i) be：

$P\left(i\right)=\frac{K\left(i\right)}{M}$

The photoelectron sum for being then incident to four single-photon detectors is respectively：

$N_S\left(i\right)=-ln\[1-P\left(i\right)\]=-ln\[1-\frac{K\left(i\right)}{M}\],$

According to four countings of single-photon detector, the light intensity of the photoelectron number form on each road is calculated respectively, bring Stokes into Parameter solution formula, and by normalized, it becomes possible to obtain the stokes parameter (S of echo-signal light₀ S₁ S₂ S₃)^T, Then the formula according to degree of polarization obtains the polarization degree information P of target：

$P=\frac{\sqrt{{S_1}^2+{S_2}^2+{S_3}^2}}{S_0}.$

4. a kind of atomic low light signals degree of polarization detection system according to claim 3, it is characterised in that Stokes is joined The acquisition system of amount includes：

Parameter setup unit：

If actual signal light stokes parameter is (S₀',S₁',S₂',S₃')^T,

The stokes parameter that detection is obtained is (S₀,S₁,S₂,S₃)^T,

Nonideal instrument matrix

Then there is relational expression：

Above-mentioned relation formula is launched to obtain：

$\begin{array}{c}{S_0}^{\′}=m_{11}{S}_0+m_{12}{S}_1+m_{13}{S}_2+m_{14}{S}_3\\ {S_1}^{\′}=m_{21}{S}_0+m_{22}{S}_1+m_{23}{S}_2+m_{24}{S}_3\\ {S_2}^{\′}=m_{31}{S}_0+m_{32}{S}_1+m_{33}{S}_2+m_{34}{S}_3\\ {S_3}^{\′}=m_{41}{S}_0+m_{42}{S}_1+m_{43}{S}_2+m_{44}{S}_3\end{array},$

Instrument matrix N obtaining unit：

N regulation is carried out to the emission part polarizer (120) and emission part quarter wave plate (130) so that each single-photon detector is obtained N kinds detect light, the equation set up between n stokes parameter and instrument matrix element：

S₀'¹=m₁₁S₀ ¹+m₁₂S₁ ¹+m₁₃S₂ ¹+m₁₄S₃ ¹

S₁'¹=m₂₁S₀ ¹+m₂₂S₁ ¹+m₂₃S₂ ¹+m₂₄S₃ ¹

S₂'¹=m₃₁S₀ ¹+m₃₂S₁ ¹+m₃₃S₂ ¹+m₃₄S₃ ¹

S₃'¹=m₄₁S₀ ¹+m₄₂S₁ ¹+m₄₃S₂ ¹+m₄₄S₃ ¹

S₀'²=m₁₁S₀ ²+m₁₂S₁ ²+m₁₃S₂ ²+m₁₄S₃ ²

S₁'²=m₂₁S₀ ²+m₂₂S₁ ²+m₂₃S₂ ²+m₂₄S₃ ²

S₃'ⁿ=m₄₁S₀ ⁿ+m₄₂S₁ ⁿ+m₄₃S₂ ⁿ+m₄₄S₃ ⁿ

One least square solution is given to above equation, and then near the instrument matrix N of actual value；

Stokes parameter obtaining unit：

The stokes parameter for being incident to each single-photon detector is instead released using above-mentioned instrument matrix N.

5. a kind of detection method of atomic low light signals degree of polarization detection system is based on, it is characterised in that the system includes：Hair Penetrate portion and acceptance division；

Emission part includes：Pulse laser (110), the emission part polarizer (120), emission part quarter wave plate (130), transmitting optics System (140) and pseudorandomcode controller (150),

The coded sequence letter of coded sequence signal output end connection pulse laser (110) of pseudorandomcode controller (150) Number input, the pulse laser that pulse laser (110) sends sequentially passes through the emission part polarizer (120) and the ripple of emission part 1/4 Piece (130) is transmitted through optical transmitting system (140), optical transmitting system (140) collimator and extender is carried out to incident light and outgoing extremely Target to be detected；

Acceptance division includes：Receiving optics (210), optical splitter (221), No. two optical splitters (222), No. three optical splitters (223), acceptance division quarter wave plate (230), number polarizer (241) of acceptance division, acceptance division No. two polarizers (242), acceptance divisions three Number polarizer (243), single-photon detector (251), No. two single-photon detectors (252), No. three single-photon detectors (253), No. four single-photon detectors (254) and symbol converter (270),

Receiving optics (210) is for focusing on and gathers the flashlight that detection target is returned, and receiving optics (210) go out It is a transmitted light and a reflected light that light is penetrated through the beam splitting of an optical splitter (221), and a transmitted light is through No. two optical splitters (222) Beam splitting is No. two transmitted lights and No. two reflected lights, and a reflected light is No. three transmitted lights and three through the beam splitting of No. three optical splitters (223) Number reflected light, No. two reflected lights sequentially pass through number polarizer (241) of acceptance division quarter wave plate (230) and acceptance division and are transmitted through two On the photosurface of number single-photon detector (252), No. two transmitted lights are transmitted through No. three lists by No. three polarizers (243) of acceptance division On the photosurface of photon detector (253), No. three transmitted lights are incident on a photosurface for single-photon detector (251), and three Number reflected light is transmitted through on No. four photosurfaces of single-photon detector (254) by No. two polarizers (242) of acceptance division, pseudorandom The coded sequence signal input of coded sequence signal output end connection symbol converter (270) of coding controller (150)；

Methods described comprises the following steps：

Flashlight debugging step：

Open pulse laser (110) so that single-photon detector (251), No. two single-photon detectors (252), No. three Single-photon detector (253) and No. four single-photon detectors (254) can receive echo-signal light；

Stokes parameter setting procedure：

If the stokes parameter of the echo-signal light of receiving optics (210) collection is：

(S₀ S₁ S₂ S₃)^T

Wherein, S₀、S₁、S₂、S₃It is respectively four parameters of normalized stokes parameter,

Because echo-signal light is divided into four tunnels by an optical splitter (221), No. two optical splitters (222) and No. three optical splitters (223), If the overall strength of echo letter light number is I₀, then it is per the strength S tokes of echo-signal light stokes parameter all the way：

$Stokes=\frac{I_0}{4}\left(\begin{array}{c}{S}_0\\ S_1\\ S_2\\ S_3\end{array}\right);$

The corresponding light intensity of detector obtains step：

The stokes parameter Stokes1 of No. four single-photon detectors (254) is：

Wherein,It is 90 ° of acting matrixes of the analyzer of placement, and

Then single-photon detector (254) responds light intensity I_s(1) it is：

$I_s\left(1\right)=\frac{I_0}{8}(S_0-S_1),$

Above formula is expressed as the form N of photoelectron number_s(1), as：

$N_s\left(1\right)=\frac{I_s\left(1\right)}{h\mathrm{\υ}}=\frac{I_0}{8h\mathrm{\υ}}(S_0-S_1);$

Wherein h is planck constant, and υ is the frequency of light

The stokes parameter Stokes2 of No. three single-photon detectors (253) is：

Then No. three single-photon detectors (253) respond light intensity I_s(2) it is：

$I_s\left(2\right)=\frac{1}{8}(S_0+S_2),$

Above formula is expressed as the form N of photoelectron number_s(2), as：

$N_s\left(2\right)=\frac{I_s\left(2\right)}{h\mathrm{\υ}}=\frac{I_0}{8h\mathrm{\υ}}(S_0+S_2);$

The stokes parameter Stokes3 of No. two single-photon detectors (252) is：

Then No. two single-photon detectors (252) respond light intensity I_s(3) it is：

$I_s\left(3\right)=\frac{1}{8}(S_0-S_3),$

Above formula is expressed as the form N of photoelectron number_s(3), as：

$N_s\left(3\right)=\frac{I_s\left(3\right)}{h\mathrm{\υ}}=\frac{I_0}{8h\mathrm{\υ}}(S_0-S_3);$

The stokes parameter Stokes1 of a number single-photon detector (251) is：

$Stokes1=Stokes=\frac{I_0}{4}\left(\begin{array}{c}{S}_0\\ S_1\\ S_2\\ S_3\end{array}\right),$

Then a single-photon detector (251) responds light intensity I_s(4) it is：

$I_s\left(4\right)=\frac{I_0}{4}{S}_0,$

Above formula is expressed as the form N of photoelectron number_s(4), as：

$N_s\left(4\right)=\frac{I_s\left(4\right)}{h\mathrm{\υ}}=\frac{I_0}{4h\mathrm{\υ}}{S}_0;$

Polarization degree information obtains step：

Derivation simultaneous according to four road signals can obtain the relation of stokes parameter and four detector signal intensity, i.e., this Lentor parameter solution formula：

$\left(\begin{array}{c}{S}_0\\ S_1\\ S_2\\ S_3\end{array}\right)=\frac{4h\mathrm{\υ}}{I_0}\left(\begin{array}{c}{N}_s\left(4\right)\\ N_s\left(4\right)-2N_s\left(1\right)\\ 2N_s\left(2\right)-N_s\left(4\right)\\ N_s\left(4\right)-2N_s\left(3\right)\end{array}\right)$

If the pulse number of pulse laser (110) transmitting is M, the intensity of atomic dim light is entered in four single-photon detectors During row measurement, the snowslide umber of pulse of the i-th road signal is K (i), i=1,2,3,4, then detection probability P (i) be：

$P\left(i\right)=\frac{K\left(i\right)}{M}$

The photoelectron sum for being then incident to four single-photon detectors is respectively：

$N_S\left(i\right)=-ln\[1-P\left(i\right)\]=-ln\[1-\frac{K\left(i\right)}{M}\],$

According to four countings of single-photon detector, the light intensity of the photoelectron number form on each road is calculated respectively, bring Stokes into Parameter solution formula, and by normalized, it becomes possible to obtain the stokes parameter (S of echo-signal light₀ S₁ S₂ S₃)^T, Then the formula according to degree of polarization obtains the polarization degree information P of target：

$P=\frac{\sqrt{{S_1}^2+{S_2}^2+{S_3}^2}}{S_0}.$

6. detection method according to claim 5, it is characterised in that the preparation method of stokes parameter includes following step Suddenly：

Parameter setting procedure：

If actual signal light stokes parameter is (S₀',S₁',S₂',S₃')^T,

The stokes parameter that detection is obtained is (S₀,S₁,S₂,S₃)^T,

Nonideal instrument matrix

Then there is relational expression：

Above-mentioned relation formula is launched to obtain：

$\begin{array}{c}{S_0}^{\′}=m_{11}{S}_0+m_{12}{S}_1+m_{13}{S}_2+m_{14}{S}_3\\ {S_1}^{\′}=m_{21}{S}_0+m_{22}{S}_1+m_{23}{S}_2+m_{24}{S}_3\\ {S_2}^{\′}=m_{31}{S}_0+m_{32}{S}_1+m_{33}{S}_2+m_{34}{S}_3\\ {S_3}^{\′}=m_{41}{S}_0+m_{42}{S}_1+m_{43}{S}_2+m_{44}{S}_3\end{array},$

Instrument matrix N obtains step：

N regulation is carried out to the emission part polarizer (120) and emission part quarter wave plate (130) so that each single-photon detector is obtained N kinds detect light, the equation set up between n stokes parameter and instrument matrix element：

S₀'¹=m₁₁S₀ ¹+m₁₂S₁ ¹+m₁₃S₂ ¹+m₁₄S₃ ¹

S₁'¹=m₂₁S₀ ¹+m₂₂S₁ ¹+m₂₃S₂ ¹+m₂₄S₃ ¹

S₂'¹=m₃₁S₀ ¹+m₃₂S₁ ¹+m₃₃S₂ ¹+m₃₄S₃ ¹

S₃'¹=m₄₁S₀ ¹+m₄₂S₁ ¹+m₄₃S₂ ¹+m₄₄S₃ ¹

S₀'²=m₁₁S₀ ²+m₁₂S₁ ²+m₁₃S₂ ²+m₁₄S₃ ²

S₁'²=m₂₁S₀ ²+m₂₂S₁ ²+m₂₃S₂ ²+m₂₄S₃ ²

S₃'ⁿ=m₄₁S₀ ⁿ+m₄₂S₁ ⁿ+m₄₃S₂ ⁿ+m₄₄S₃ ⁿ

One least square solution is given to above equation, and then near the instrument matrix N of actual value；

Stokes parameter obtains step：

The stokes parameter for being incident to each single-photon detector is instead released using above-mentioned instrument matrix N.