CN103115683A - Method of measuring monochromatic light polarization state - Google Patents

Abstract

The invention discloses a method of measuring a monochromatic light polarization state and belongs to the technical field of photoelectric detecting. The method of measuring the monochromatic light polarization state solves the problems that an existing measuring method of a light polarization state can just measure a specific wavelength and efficiency is low. The method of measuring the monochromatic light polarization state is sequentially provided with a main polarization piece and a charge coupled device (CCD) detector along a direction vertical to the direction from which a monochromatic light path is emitted so that monochromatic light goes through the main polarization piece and is emitted to a light receiving face of the CCD detector. The direction of a light shaft of the monochromatic light is taken as the direction of a Z axis of a three-dimensional coordinate system. By collection of the CCD detector, transmission light intensity is obtained after the emitted monochromatic light goes through the main polarization piece, the main polarization piece is rotated for N times so that included angles of a transmission light shaft and a Y axis are different after every rotation of the main polarization piece. Every time the main polarization piece is rotated, transmission light intensity is collected, and calculation is performed. The emitted monochromatic light polarization state is obtained according to calculation of all the included angles of the transmission light shaft and the Y axis of the main polarization state and transmission light intensity correspondingly collected and obtained by the CCD detector. The method of measuring the monochromatic light polarization state is suitable for measuring monochromatic light polarization states.

Description

Measure the method for monochromatic light polarization state

Technical field

The present invention relates to measure the method for monochromatic light polarization state, belong to photoelectric detection technology field.

Background technology

Polarized light has a wide range of applications in science and technology and commercial production.The development that the measuring technique of polarized light is also used along with polarized light.

Use at present maximum stokes parameter measuring methods that are.Its measuring principle is that in light path to be measured, the optical axis direction of adjusting polaroid and quarter wave plate is measured and obtained transmitted light intensity, by the calculating of output signal being tried to achieve the Stokes Stokes parameter for the treatment of photometry.Can by polaroid optical axis and quarter wave plate quick shaft direction in the rotation light path, obtain at least 6 group light intensity values during measurement; Also can be first after the incident light light splitting, record light intensity after the different optical axises that every Shu Guang process fixes and the polaroid of quick shaft direction and quarter wave plate combination.Because the method has been used quarter wave plate, a specific device can only be measured for the light of a certain specific wavelength, need to change quarter wave plate corresponding to its wavelength when measuring other wavelength light, and this has limited the efficient of polarized light measurement to a great extent.

Summary of the invention

The present invention can only measure for the light of a certain specific wavelength the measuring method of polarisation of light attitude in order to solve to have now, and inefficient problem provides a kind of method of measuring the monochromatic light polarization state.

The method of measurement monochromatic light polarization state of the present invention, it comprises the following steps:

Step 1: along arranging successively main polaroid and ccd detector perpendicular to the direction of incident monochromatic light light path, make monochromatic light be incident to the light receiving surface of ccd detector after main polaroid, wherein the direction of monochromatic light optical axis is as the Z-direction of three-dimensional system of coordinate;

Step 2: obtain the transmitted light intensity of incident monochromatic light after main polaroid by the ccd detector collection;

Step 3: rotate main polaroid N time, make the each postrotational light transmission shaft of main polaroid different from the angle of Y-axis, after rotating main polaroid at every turn, repeating step two; Then execution in step four; Wherein N is equal to, or greater than 6 natural number;

Step 4: calculate the monochromatic polarization state of acquisition incident with angle and the corresponding transmitted light intensity that obtains that gathers of ccd detector of Y-axis according to the light transmission shaft of each main polaroid.

It is further comprising the steps of:

Step 5: the XY rotation with in surface Y direction in three-dimensional system of coordinate, then calculate the monochromatic polarization state of acquisition incident according to the method in step 4, and judge that obtaining incident monochromatic light is elliptically polarized light or partial poolarized light.

It is further comprising the steps of:

Step 6: the direction perpendicular to the monochromatic light light path before ccd detector arranges additional polaroid;

Step 7: obtain the transmitted light intensity of incident monochromatic light after additional polaroid by the ccd detector collection; Then execution in step three and step 4, and judge that obtaining incident monochromatic light is circularly polarized light or natural light.

Calculating the concrete grammar that obtains the monochromatic polarization state of incident in step 4 is:

Transmitted light intensity I according to ccd detector collection acquisition:

$I=E_x^2{\sin }^2\mathrm{\&theta;}+E_y^2{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA00002762346300011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&theta;}+E_x{E}_y\sin 2\mathrm{\&theta;}\cos \mathrm{\&alpha;}+\frac{I_0}{2}+n(E_x^2{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA00002762346300011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&theta;}+E_y^2{\sin }^2\mathrm{\&theta;}+E_x{E}_y\sin 2\mathrm{\&theta;}\cos \mathrm{\&alpha;}+\frac{I_0}{2}),$

$=({\sin }^2\mathrm{\&theta;}+\mathrm{<figure-callout\; id="2"\; label="n\; cos"\; filenames="HDA00002762346300011.png"\; state="\{\{state\}\}">n</figure-callout>}{\cos }^{}{}^2\mathrm{\&theta;})E_x^2+({\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA00002762346300011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&theta;}+n{\sin }^2)E_y^2+(1+n)E_x{E}_y\sin 2\mathrm{\&theta;}\cos \mathrm{\&alpha;}+(1+n)\frac{I_0}{2}$

E wherein _xBe X-direction electric field intensity intensity, E _yBe Y direction electric field intensity intensity, θ is the light transmission shaft of main polaroid and the angle of Y-axis, and α is E _yWith respect to E _yPhasic difference, I ₀Be the intensity of equivalent natural light in incident monochromatic light, n is the extinctivity of main polaroid,

With the light transmission shaft of the main polaroid of above-mentioned each acquisition and angle theta and the corresponding transmitted light intensity I substitution following formula that obtains that gathers of ccd detector of Y-axis, calculate and obtain E _x, E _y, α, I ₀, namely obtain the monochromatic polarization state of incident.

Advantage of the present invention: a main polaroid and ccd detector are only used in the realization of the inventive method, and embodiment is simple, and is workable, extremely are fit to carry out in the laboratory measuring polarization state of simple high-precision; It can measure the polarization state of any wavelength incident light, and can measure the distribution of incident light polarization state.

In people's traditional understanding, polaroid can only be distinguished linearly polarized light and elliptically polarized light.The present invention has overcome technology prejudice, has realized using polaroid to the measurement of various polarized light polarization states.

Description of drawings

Fig. 1 is the measuring principle figure of the method for measurement monochromatic light polarization state of the present invention;

Fig. 2 is the optical axis rotation schematic diagram of main polaroid; E in figure _x', E _y' be the XY rotation with in surface Y-axis in three-dimensional system of coordinate after, with E _x, E _yCorresponding variable;

Fig. 3 is the match schematic diagram of the incident monochromatic light polarization state polarization state curve theoretical with it of experiment measuring acquisition, and wherein curve is the monochromatic theoretical polarization state curve of incident, and trigpoint is the experiment measuring point.

Embodiment

Embodiment one: below in conjunction with Fig. 1 and Fig. 2, present embodiment is described, the method for the described measurement monochromatic light of present embodiment polarization state, it comprises the following steps:

Step 1: along arranging successively main polaroid 1 and ccd detector 2 perpendicular to the direction of incident monochromatic light light path, make monochromatic light be incident to the light receiving surface of ccd detector 2 after main polaroid 1, wherein the direction of monochromatic light optical axis is as the Z-direction of three-dimensional system of coordinate;

Step 2: gather by ccd detector 2 and obtain the transmitted light intensity of incident monochromatic light after main polaroid 1;

Step 3: rotate main polaroid 1N time, make the each postrotational light transmission shaft of main polaroid 1 different from the angle of Y-axis, after rotating main polaroid 1 at every turn, repeating step two; Then execution in step four; Wherein N is equal to, or greater than 6 natural number;

Step 4: calculate the monochromatic polarization state of acquisition incident with angle and the corresponding transmitted light intensity that obtains that gathers of ccd detector 2 of Y-axis according to the light transmission shaft of each main polaroid 1.

Embodiment two: present embodiment is for to the further illustrating of embodiment one, and present embodiment is further comprising the steps of:

Step 5: the XY rotation with in surface Y direction in three-dimensional system of coordinate, then calculate the monochromatic polarization state of acquisition incident according to the method in step 4, and judge that obtaining incident monochromatic light is elliptically polarized light or partial poolarized light.

Present embodiment can't be distinguished elliptically polarized light and partial polarization light time at embodiment one, be cos α=0 o'clock, the step of carrying out, it is by the rotation three-dimensional system of coordinate, the light transmission shaft of main polaroid 1 and the angle theta of Y-axis are changed, recomputate and to solve the monochromatic polarization state of incident.

Embodiment three: present embodiment is for to the further illustrating of embodiment two, and present embodiment is further comprising the steps of:

Step 6: the direction perpendicular to the monochromatic light light path before ccd detector 2 arranges additional polaroid 3;

Step 7: gather by ccd detector 2 and obtain the transmitted light intensity of incident monochromatic light after additional polaroid 3; Then execution in step three and step 4, and judge that obtaining incident monochromatic light is circularly polarized light or natural light.

Described in present embodiment, additional 3 of polaroids just can be used in the time can't distinguishing circularly polarized light and natural light, and the not corresponding specific wavelength of this additional polaroid 3 is any one polaroid.

Embodiment four: below in conjunction with Fig. 1 to Fig. 3, present embodiment is described, present embodiment is for to embodiment one, two or three further illustrate, and calculates the concrete grammar that obtains the monochromatic polarization state of incident in the described step 4 of present embodiment and is:

Gather according to ccd detector 2 the transmitted light intensity I that obtains:

$I=E_x^2{\sin }^2\mathrm{\&theta;}+E_y^2{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA00002762346300011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&theta;}+E_x{E}_y\sin 2\mathrm{\&theta;}\cos \mathrm{\&alpha;}+\frac{I_0}{2}+n(E_x^2{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA00002762346300011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&theta;}+E_y^2{\sin }^2\mathrm{\&theta;}+E_x{E}_y\sin 2\mathrm{\&theta;}\cos \mathrm{\&alpha;}+\frac{I_0}{2}),$

$=({\sin }^2\mathrm{\&theta;}+\mathrm{<figure-callout\; id="2"\; label="n\; cos"\; filenames="HDA00002762346300011.png"\; state="\{\{state\}\}">n</figure-callout>}{\cos }^{}{}^2\mathrm{\&theta;})E_x^2+({\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA00002762346300011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&theta;}+n{\sin }^2)E_y^2+(1+n)E_x{E}_y\sin 2\mathrm{\&theta;}\cos \mathrm{\&alpha;}+(1+n)\frac{I_0}{2}$

E wherein _xBe X-direction electric field intensity intensity, E _yBe Y direction electric field intensity intensity, θ is the light transmission shaft of main polaroid 1 and the angle of Y-axis, and α is E _yWith respect to E _xPhasic difference, I ₀Be the intensity of equivalent natural light in incident monochromatic light, n is the extinctivity of main polaroid 1,

With the light transmission shaft of the main polaroid 1 of above-mentioned each acquisition and angle theta and the corresponding transmitted light intensity I substitution following formula that obtains that gathers of ccd detector 2 of Y-axis, calculate and obtain E _x, E _y, α, I ₀, namely obtain the monochromatic polarization state of incident.

Step 6 and step 7 are just can use in the time can't distinguishing circularly polarized light and natural light, and this result that can't the differentiation state embodies is E _x=E _y

In present embodiment, if calculate respectively the polarization state of the incident light of each sensing point on ccd detector 2, the polarization state that can measure the incident light xsect distributes.

As shown in Figure 3, adopt the inventive method higher to the measuring accuracy of monochromatic light polarization state, better with the fitting effect of theoretical polarization state curve.The inventive method has proposed only to use the method that polaroid is measured the polarisation of light attitude first, has proposed first the rotary reference coordinate system and has reappraised the polarisation of light attitude.

Claims (4)

1. a method of measuring the monochromatic light polarization state, is characterized in that, it comprises the following steps:

Step 1: along arranging successively main polaroid (1) and ccd detector (2) perpendicular to the direction of incident monochromatic light light path, make monochromatic light be incident to the light receiving surface of ccd detector (2) after main polaroid (1), wherein the direction of monochromatic light optical axis is as the Z-direction of three-dimensional system of coordinate;

Step 2: obtain the transmitted light intensity of incident monochromatic light after main polaroid (1) by ccd detector (2) collection;

Step 3: rotate main polaroid (1) N time, make the each postrotational light transmission shaft of main polaroid (1) different from the angle of Y-axis, after rotating main polaroid (1) at every turn, repeating step two; Then execution in step four; Wherein N is equal to, or greater than 6 natural number;

Step 4: calculate the monochromatic polarization state of acquisition incident with angle and the corresponding transmitted light intensity that obtains that gathers of ccd detector (2) of Y-axis according to the light transmission shaft of each main polaroid (1).

2. the method for measurement monochromatic light polarization state according to claim 1, is characterized in that, it is further comprising the steps of:

Step 5: the XY rotation with in surface Y direction in three-dimensional system of coordinate, then calculate the monochromatic polarization state of acquisition incident according to the method in step 4, and judge that obtaining incident monochromatic light is elliptically polarized light or partial poolarized light.

3. the method for measurement monochromatic light polarization state according to claim 2, is characterized in that, it is further comprising the steps of:

Step 6: additional polaroid (3) is set in the front direction perpendicular to the monochromatic light light path of ccd detector (2);

Step 7: obtain the transmitted light intensity of incident monochromatic light after additional polaroid (3) by ccd detector (2) collection; Then execution in step three and step 4, and judge that obtaining incident monochromatic light is circularly polarized light or natural light.

4. the method for according to claim 1,2 or 3 described measurement monochromatic light polarization states, is characterized in that, calculates the concrete grammar that obtains the monochromatic polarization state of incident in step 4 to be:

Gather the transmitted light intensity I of acquisition according to ccd detector (2):

$I=E_x^2{\sin }^2\mathrm{\&theta;}+E_y^2{\cos }^2\mathrm{\&theta;}+E_x{E}_y\sin 2\mathrm{\&theta;}\cos \mathrm{\&alpha;}+\frac{I_0}{2}+n(E_x^2{\cos }^2\mathrm{\&theta;}+E_y^2{\sin }^2\mathrm{\&theta;}+E_x{E}_y\sin 2\mathrm{\&theta;}\cos \mathrm{\&alpha;}+\frac{I_0}{2}),$

$=({\sin }^2\mathrm{\&theta;}+n{\cos }^2\mathrm{\&theta;})E_x^2+({\cos }^2\mathrm{\&theta;}+n{\sin }^2)E_y^2+(1+n)E_x{E}_y\sin 2\mathrm{\&theta;}\cos \mathrm{\&alpha;}+(1+n)\frac{I_0}{2}$

E wherein _xBe X-direction electric field intensity intensity, E _yBe Y direction electric field intensity intensity, θ is the light transmission shaft of main polaroid (1) and the angle of Y-axis, and α is E _yWith respect to E _xPhasic difference, I ₀Be the intensity of equivalent natural light in incident monochromatic light, n is the extinctivity of main polaroid (1),

With the light transmission shaft of the main polaroid (1) of above-mentioned each acquisition and angle theta and the corresponding transmitted light intensity I substitution following formula that obtains that gathers of ccd detector (2) of Y-axis, calculate and obtain Ex, Ey, α, I ₀, namely obtain the monochromatic polarization state of incident.

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