CN203519903U - Composite wave plate fast axis perpendicularity adjustment device - Google Patents

Abstract

The utility model discloses a composite wave plate fast axis perpendicularity adjustment device. The adjustment device comprises a polarized light source and a feedback control system. Parallel line polarized light emerged by the polarized light source sequentially passes through a first rotating disc, a second rotating disc, a polarization analyzer and a photoelectric detector. The first rotating disc, the second rotating disc, the polarization analyzer and the photoelectric detector are placed on a same transmission axis. The first rotating disc is connected with a first motor. The second rotating disc is connected with a second motor. The feedback control system is connected with the photoelectric detector, the first motor and the second motor to acquire photoelectric current data and control the rotating state of the first motor and the rotating state of the second motor through feedback. The first rotating disc and the second rotating disc are of a hollow structure. A locating device for fixing a first wave plate is arranged in the hollow structure of the first rotating disc. A locating device for fixing a second wave plate is arranged in the hollow structure of the second rotating disc. By the adoption of the composite wave plate fast axis perpendicularity adjustment device, the composite wave plate fast axis perpendicularity measurement accuracy is high, the measurement speed is high, and the composite wave plate fast axis perpendicularity adjustment device is simple, convenient to use and feasible.

Description

The fast axle perpendicularity regulating device of a kind of composite wave plate

Technical field

The utility model proposes the fast axis adjustment device of a kind of composite wave plate, particularly a kind of for regulating the high precision feedback regulation device of the fast axle verticality between each single wave plate of composite wave plate, the utility model belongs to polarization optics detection field.

Background technology

Wave plate is commonly used for the transformation device of light signal polarization state in ellipsometry or optical measurement, and its characteristic often can have a huge impact measurement result.From forming structure and using method, wave plate can be divided into single wave plate (hereinafter to be referred as single wave plate) and the large class of composite wave plate two; Composite wave plate is comprised of two or more multistage wave plates conventionally, and wherein the fast axle between adjacent wave plate is mutually vertical, is about to the fast axle of a wave plate and the slow axis of another adjacent wave plate and is parallel to each other, to obtain the gummed wave plate of required 0～π phase-delay quantity.Compare with single wave plate, composite wave plate has higher precision, even can eliminate the aberration of wave plate itself, therefore in Optical Instrument Designing and optical measurement, be applied widely, for example, based on whirl compensator, the broad sense ellipsometer of rotatable Composite Double wave plate is exhibited one's skill to the full at film and nano material fields of measurement.Wherein, the serviceability of two whirl compensators has material impact to the complete machine characteristic of broad sense ellipsometer, and its design, aligning and demarcation will directly have influence on the measuring accuracy of whole instrument.Periodical [Thin Solid Films, 455-456,14 – 23 (2004)] mention, in the Design and manufacturing process of ellipsometer, must guarantee each whirl compensator used, be that in composite wave plate, the fast axle of two single wave plates is strictly vertical, otherwise can cause that the phase differential through whirl compensator produces the higher-order of oscillation

In production application, the regulative mode of the fast axle verticality of composite wave plate divides two kinds of manual adjustments and motorized adjustment.Manual adjustments height depends on operating personnel's experience; Take Composite Double wave plate as example, first fix one of them single wave plate, another single wave plate of manual rotation then, when being observed visually the actual phase of composite wave plate and postponing to approach ideal value, think regulate complete.Although this mode operating process is relatively simple, the precision of fast axle verticality is difficult to guarantee, in the higher occasion of accuracy requirement, is often difficult to meet realistic accuracy requirement.Periodical [J.Opt.Soc.Am.A, 18,1980 (2001)] mention, electronic aligning aspect, the fast axle verticality that the people such as the Collins of Pennsylvania State Univ-Univ Park USA realize Composite Double wave plate by means of rotation analyzer formula ellipsometer regulates the method that Composite Double wave plate is regarded as to special test sample and measured, calculates its compound phase potential difference, with this, instruct the relative position that regulates the fast axle of double wave sheet, although degree of regulation is higher, but adjustment process relative complex, and final degree of regulation and operating personnel's experience has compared with Important Relations.In addition, in Chinese patent CN201110350098.X and CN201110349669.8, two single wave plates of Composite Double wave plate are set to respectively fixed and rotatable, utilize the method (similar to the measurement mechanism of rotation analyzer formula ellipsometer) of rotation analyzer to measure, calculate its compound phase potential difference, the rotation of instructing second single wave plate with this, the fast axle verticality realizing between two single wave plates regulates.As described in patent CN201110350098.X, the key of motorized adjustment method and apparatus is the running accuracy of control motor used (for directly or indirectly driving wave plate or analyzer rotation).; existing electronic alignment methods is to be all based upon on the hypothesis that motor has high running accuracy; all do not consider the error that the true running accuracy of motor self is introduced; more do not consider the error that the objective factor such as light source intensity fluctuation is introduced, this just causes always existing between practical adjustments result and ideal value certain error.So, how to take into full account under the condition of actual device measuring error, realize quick, the high precision alignment of the fast axle verticality of composite wave plate, remain a major issue to be solved.

Summary of the invention

The purpose of this utility model is to overcome the deficiency that prior art exists, provide a kind of for regulating the high precision feedback regulation device of the fast axle verticality between each single wave plate of composite wave plate, this device can be in the situation that several single wave plate quick shaft directions of composite wave plate be all unknown, the quick shaft direction of each single wave plate of fast detecting, and realize fast detecting and the high precision feedback regulation of fast axle verticality between adjacent single wave plate in composite wave plate.

The utility model adopts following technical scheme:

The fast axle perpendicularity regulating device of a kind of composite wave plate, comprise polarized light source, feedback control system, the parallel lines polarized light of polarized light source outgoing is successively by transmission axle is placed altogether the first rotating disk, the second rotating disk, analyzer, photodetector, the first rotating disk is connected with the first motor, and the second rotating disk is connected with the second motor; The same photodetector of feedback control system, the first motor, the second motor are connected and realize the rotation status of collection analysis photocurrent data FEEDBACK CONTROL the first motor and the second motor; Described the first rotating disk and the second rotating disk are hollow structure, in described the first rotating disk hollow structure, are provided with the locating device of fixing the first wave plate, in described the second rotating disk hollow structure, are provided with the locating device of fixing the second wave plate.

Described feedback control system is provided with the relational expression of the error of perpendicularity Δ θ that calculates the first wave plate and the fast axle of the second wave plate:

$\mathrm{\&Delta;\&theta;}=\left\{\begin{array}{cc}\sqrt{\frac{{(1+\cos {\mathrm{\&delta;}}_1)}^2}{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2}\&CenterDot;\left\{\right[\frac{I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{]}^2-{{\mathrm{\&sigma;}}_F}^2\}-{\mathrm{\&Delta;\&alpha;}}^2}& I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})\&GreaterEqual;I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})\\ -\sqrt{\frac{{(1+\cos {\mathrm{\&delta;}}_1)}^2}{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2}\&CenterDot;\left\{\right[\frac{I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}-{{\mathrm{\&sigma;}}_F}^2\}-{\mathrm{\&Delta;\&alpha;}}^2}& I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})<I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})\end{array}\right.$

Wherein, α is that the fast axle of the first wave plate is with respect to the absolute anglec of rotation of reference position; θ is the actual angle of the first wave plate and the fast between centers of the second wave plate; σ _ffor in regulating device with α and the irrelevant known fixed error of θ; δ ₁, δ ₂be respectively the phase-delay quantity of the first wave plate and the second wave plate; Δ α is the running accuracy of the first rotating disk and the second rotating disk; I _measurephotocurrent data when (α, θ) gathers α=k π+pi/2 for feedback control system, k is nonnegative integer; I _idealdesired light current value when (k π+pi/2, pi/2) is α=k π+pi/2, it is as follows that it obtains expression formula:

$I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})=\left\{\begin{array}{cc}{I}_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;\frac{1+\cos {\mathrm{\&delta;}}_1}{1+\cos {\mathrm{\&delta;}}_2}\&CenterDot;[1-\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;{\mathrm{\&Delta;\&alpha;}}^2}{(1+\cos {\mathrm{\&delta;}}_2{)}^2}}]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&GreaterEqual;\frac{K}{2}\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;I_i\&CenterDot;(1+\cos {\mathrm{\&delta;}}_2)\\ I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;\frac{1+\cos {\mathrm{\&delta;}}_1}{1+\cos {\mathrm{\&delta;}}_2}\&CenterDot;[1+\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;\mathrm{\&Delta;}{\mathrm{\&alpha;}}^2}{{(1+\cos {\mathrm{\&delta;}}_2)}^2}}]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})<\frac{K}{2}\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;I_i\&CenterDot;(1+\cos {\mathrm{\&delta;}}_2)\end{array}\right.$

Wherein, the quantum efficiency that K is photodetector, L are insertion loss, the I of feedback regulation device _iinput light intensity, I for polarized light source _measure(α, θ) is the photocurrent data of feedback control system collection α=k π.

Described polarized light source is linear polarization light source or the wavelength adjustable type polarized light source that output characteristics is stable.

The rotation precision of described the first rotating disk and the second rotating disk is all less than the Δ θ error margin of setting in feedback control system.

The utlity model has following beneficial effect:

The purpose of this utility model is to provide fast detecting and the high precision feedback regulation device of the fast axle verticality of a kind of composite wave plate, this device can be in the situation that several single wave plate quick shaft directions of composite wave plate be all unknown, the quick shaft direction of each single wave plate of fast detecting, and realize in composite wave plate fast detecting and the high precision feedback regulation of fast axle verticality between adjacent single wave plate, its actual degree of regulation can not be subject to the true running accuracy of motor and rotating disk in measurement mechanism, and the impact of light source intensity fluctuating error in device, measuring accuracy is high, measuring speed is fast and simple and easy to do.

Accompanying drawing explanation

Fig. 1 is the basic structure schematic diagram of the fast axle verticality of the related composite wave plate of the utility model feedback regulation device;

Fig. 2 is for adopting the utility model device to carry out the fast detecting of the fast axle verticality of composite wave plate and the process flow diagram of feedback regulation;

Wherein:

1, polarized light source;

2, the first rotating disk;

3, the second rotating disk;

4, analyzer;

5, photodetector;

6, feedback control system;

7, the first motor;

8, the second motor;

9, the first wave plate;

10, the second wave plate;

Embodiment

Below in conjunction with embodiment, the utility model is described in detail.

The fast detecting of the fast axle verticality of a kind of composite wave plate described in the utility model and the structure of high precision feedback regulation device are as shown in Figure 1, comprise a polarized light source 1, feedback control system 6, the parallel lines polarized light of polarized light source 1 its outgoing is successively by transmission axle is placed altogether the first rotating disk 2, the second rotating disk 3 and analyzer 4, by the photodetector 5 that altogether transmission axle is placed, received and be transformed into photocurrent, the rotation status of feedback control system 6 collection analysis photocurrent data FEEDBACK CONTROL the first motor 7 and the second motor 8; The first rotating disk 2 is connected with the first motor 7, and the second rotating disk 3 is connected with the second motor 8, and photodetector 5, the first motor 7, the second motor 8 are connected with feedback control system 6.Described the first rotating disk 2 and the second rotating disk 3 are hollow structure, in the hollow structure of the first rotating disk 2 and the second rotating disk, be provided with locating device, in the present embodiment, adopt the periphery of hollow structure to have a plurality of pilot holes, by this pilot hole, the first wave plate 9 and the second wave plate 10 are separately fixed to the hollow structure part of the first rotating disk 2 and the second rotating disk 3; And by the first motor 7 and the second motor 8, controlled respectively the rotation status of the first rotating disk 2 and the second rotating disk 3.

Described light source 1 is the linear polarization light source that output characteristics is stable, also can after the stable lamp of output characteristics, place the polarizer and obtain linearly polarized light, its output wavelength can specifically be selected according to the operation wavelength of the first wave plate 9 and the second wave plate 10, also may be selected to be wavelength adjustable type polarized light source.In concrete application, can add necessary expand-collimation lens set according to the spot size of this light source and beam quality.

The application requirements of described the first rotating disk 2 and the second rotating disk 3 is that the rotation precision of two rotating disks all should be less than the Δ θ error margin of setting in feedback control system 6, and common commercial product all can meet this application requirements.

Described analyzer 4 can adopt a kind of in dichroic polarizer or birefringent polarizer.

Described photodetector 5 is photodiode, photomultiplier or CCD(Charge-coupled Device) linear array or area array sensor, carry out data processing for the photo-signal detecting is reached to computing machine through data collecting card.

After the photocurrent data that described feedback control system 6 collection analysis photodetectors 5 detect, photocurrent data when especially the fast axle of the first wave plate 9 is α=k π and α=k π+pi/2 with respect to the absolute anglec of rotation α of reference position, send pulse signal according to certain feedback control algorithm and through motor driver, adjust the rotation status of motor.

Described the first motor 7 and the second motor 8 and motor driver thereof are selected servomotor, p-m step motor or reaction stepping motor, and the motor driver matching with the motor of above every type.Because the first rotating disk 2 in the utility model is connected with the first motor 7, the second rotating disk 3 is connected with the second motor 8, and by the first motor 7 and the second motor 8, controlled respectively the rotation status of the first rotating disk 2 and the second rotating disk 3, in practical application, also can select the integrated electric rotary commodity that are produced on together of single motor and single rotating disk to be come respectively as the first rotating disk 2 being connected and the first motor 7, and the second rotating disk 3 being connected and the second motor 8.

Described the first wave plate 9 and the second wave plate 10 are all the single wave plate by crystalline material or polymeric material, or by single wave plate composite wave plate glued together.

The process of the fast detecting of the fast axle verticality of a kind of composite wave plate described in the utility model and high precision feedback regulation device practical function is as follows:

The parallel lines polarized light of polarized light source 1 outgoing is successively by after transmission axle is placed altogether the first rotating disk 2, the second rotating disk 3 and analyzer 4, by the photodetector 5 that altogether transmission axle is placed, received and be transformed into photocurrent, photocurrent data are after feedback control system 6 collection analysises, according to certain feedback control algorithm, control the rotation status of the first motor 7 and the second motor 8, realize fast detecting and the high precision feedback regulation of the fast axle verticality of composite wave plate.Described the first rotating disk 2 and the second rotating disk 3 can be distinguished clamping, fixing the first wave plate 9 and the second wave plate 10 to be connected; The first rotating disk 2 and the first rotating disk 3 are controlled respectively its rotation status by the first motor 7 and the second motor 8.

Innovative point of the present utility model is, measuring method described in the utility model can be in the situation that several single wave plate quick shaft direction the unknowns of composite wave plate, the quick shaft direction of each single wave plate of fast detecting, and realize fast detecting and the high precision feedback regulation of axle verticality soon between two single wave plates.Below in conjunction with accompanying drawing 2, with in Composite Double wave plate between two single wave plates fast axle verticality be adjusted to example, principle of work and the regulating step of the fast axle perpendicularity regulating device of composite wave plate are presented below:

Step 1: regulate analyzer parallel with the polarization direction of polarized light source 1: open the fast axle alignment device of composite wave plate described in the utility model, guarantee all light path devices transmission axle placement altogether in measurement mechanism.Under the first wave plate 9 and the default state of the second wave plate 10, if the polarization direction of polarized light source 1 output optical signal is adjustable, regulate the polarization direction of polarized light source 1; Otherwise regulate the polarization axle orientation of the known analyzer 4 of polarization axis direction; Search the output photoelectric stream corresponding analyzer polarization axle of maximal value orientation, this orientation is the polarization axle position parallel with the polarization light output polarization direction of polarized light source 1 of analyzer 4.Step 1 is the operation steps of the fast axle alignment device of wave plate when enabling at first, and its operation object is to guarantee that polarized light source 1 is identical with the polarization direction of analyzer 4, in the repetition measurement of continued operation, conventionally can omit.

Step 2: the first wave plate 9, the second wave plate 10 are individually fixed on the locating device of the first rotating disk 2, the second rotating disk 3, regulate the fast axle of the first wave plate 9 and the second wave plate 10, make two wave plate quick shaft directions basic mutually vertical.Owing to all can having certain human error in the process of the fast axle of mark and adjustment process, so this is adjusted to coarse adjustment.

Wherein, between described step 1 and step 2, also comprise the steps:

Steps A: search the fast axis direction of the second wave plate 10, carry out after mark, it is taken off from the second rotating disk 3;

Step B: search the fast axis direction of the first wave plate 9, and carry out mark, then the second wave plate 10 is put back to the second rotating disk 3;

The specific implementation of searching the fast axis direction of wave plate in described steps A, step B is: wave plate is fixed on corresponding rotating disk, guarantees and light path devices transmission axle placement altogether, rotary turnplate is until the photocurrent of photodetector output reaches maximal value.For the first known wave plate 9 of quick shaft direction and the second wave plate 10, steps A and step B can omit conventionally.

Step 3: simultaneously start the first motor 7 and the second motor 8, the first motor 7 drives the first rotating disk 2 rotations that are loaded with the first wave plate 9, the second motor 8 drives the second rotating disk 3 rotations that are loaded with the second wave plate 10, and the first rotating disk 2 and angular velocity of rotation identical with the second rotating disk 3 sense of rotation is w.In the situation that system performance is stable, if the fast axle of the first wave plate 9 is denoted as to α (α=wt with respect to the absolute anglec of rotation of reference position, the initial time of t=0 is corresponding to α=0, after this every rotation half cycle of rotating disk, the value of α increases π, if rotating disk starts to rotate k week from the initial time of t=0, the value of α is just increased to 2k π from 0, wherein k is nonnegative integer), and the actual angle of the first wave plate 9 and the second wave plate 10 fast between centers is denoted as to θ; Owing to should have θ=pi/2 when two fast axles of wave plate are completely vertical, by the concrete theoretical analysis about step 3 below, can find out, the error of perpendicularity Δ θ of the fast axle of two wave plates is exactly photocurrent function I (α, θ) at θ=pi/2 place about the differentiate micro component of the θ that obtains of θ, have Δ θ=θ-pi/2; Photocurrent data I when feedback control system 6 collection α get special angle α=k π and α=k π+pi/2 _measure(α, θ), wherein k is nonnegative integer, feedback control system 6 New count of automatically the value zero clearing of k being laid equal stress on when step 3 starts to carry out at every turn, and also the first rotating disk 2 and the second rotating disk 3 often rotate a circle, and the numerical value of k increases by 2; The following relational expression arranging in feedback control system 6, calculates the error of perpendicularity Δ θ of the fast axle of two wave plates;

$\mathrm{\&Delta;\&theta;}=\left\{\begin{array}{cc}\sqrt{\frac{{(1+\cos {\mathrm{\&delta;}}_1)}^2}{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2}\&CenterDot;\left\{\right[\frac{I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{]}^2-{{\mathrm{\&sigma;}}_F}^2\}-{\mathrm{\&Delta;\&alpha;}}^2}& I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})\&GreaterEqual;I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})\\ -\sqrt{\frac{{(1+\cos {\mathrm{\&delta;}}_1)}^2}{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2}\&CenterDot;\left\{\right[\frac{I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}-{{\mathrm{\&sigma;}}_F}^2\}-{\mathrm{\&Delta;\&alpha;}}^2}& I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})<I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})\end{array}\right.$

Wherein, θ is the actual angle of the first wave plate 9 and the second wave plate 10 fast between centers, σ _ffor in regulating device with α and the irrelevant known fixed error of θ; δ ₁, δ ₂be respectively the phase-delay quantity of the first wave plate 9 and the second wave plate 10; I _measurephotocurrent data when (α, θ) is feedback control system (6) collection α=k π+pi/2, k is nonnegative integer; Δ α is the running accuracy of the first rotating disk 2 and the second rotating disk 3; I _idealdesired light current value when (k π+pi/2, pi/2) is α=k π+pi/2, its expression formula is as follows:

$I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})=\left\{\begin{array}{cc}{I}_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;\frac{1+\cos {\mathrm{\&delta;}}_1}{1+\cos {\mathrm{\&delta;}}_2}\&CenterDot;[1-\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;{\mathrm{\&Delta;\&alpha;}}^2}{(1+\cos {\mathrm{\&delta;}}_2{)}^2}}]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&GreaterEqual;\frac{K}{2}\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;I_i\&CenterDot;(1+\cos {\mathrm{\&delta;}}_2)\\ I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;\frac{1+\cos {\mathrm{\&delta;}}_1}{1+\cos {\mathrm{\&delta;}}_2}\&CenterDot;[1+\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;\mathrm{\&Delta;}{\mathrm{\&alpha;}}^2}{{(1+\cos {\mathrm{\&delta;}}_2)}^2}}]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})<\frac{K}{2}\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;I_i\&CenterDot;(1+\cos {\mathrm{\&delta;}}_2)\end{array}\right.$

In above formula, K is the quantum efficiency of photodetector 5, insertion loss, the I that L is feedback regulation device _iinput light intensity, I for polarized light source 1 _measure(α, θ) is the photocurrent data that feedback control system (6) gathers α=k π.

In the feedback regulation process described in step 3, for further reducing error, feedback control system 6 can gather k=0, and 1 ..., many groups I during k _measure(α, θ) data, comprise I _measure(0, θ), I _measure(pi/2, θ) ... I _measure(k π, θ) and I _measure(k π+pi/2, θ), wherein the value of nonnegative integer k can be selected the real needs of practical adjustments device governing speed and error margin Δ θ according to device operating personnel; By the relational expression of its setting

$\stackrel{\&OverBar;}{I_{\mathrm{measure}}}(0,\mathrm{\&theta;})=\sqrt{\frac{{\left[I_{\mathrm{measre}}(0,\mathrm{\&theta;})\right]}^2+{\left[I_{\mathrm{measure}}(\mathrm{\&pi;},\mathrm{\&theta;})\right]}^2+...+{\left[I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\right]}^2}{k}};$

$\stackrel{\&OverBar;}{I_{\mathrm{measure}}}(\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})=\sqrt{\frac{{\left[I_{\mathrm{measure}}(\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})\right]}^2+{\left[I_{\mathrm{measure}}(\frac{3\mathrm{\&pi;}}{2},\mathrm{\&theta;})\right]}^2+...+{\left[I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})\right]}^2}{k}};$

Calculate r.m.s.

with

with it, replace respectively I _measure(k π, θ) and I _measure(k π+pi/2, θ), in substitution feedback control system 6, arrange about Δ θ and I _idealthe expression formula of (k π+pi/2, pi/2), calculates Δ θ.

Step 4: judge whether result of calculation meets the default Δ θ error margin of feedback control system 6.When meeting specification error tolerance limit, feedback regulation finishes; When not meeting specification error tolerance limit, according to the size of Δ θ calculated value and positive and negative, to the second rotating disk 3, select its rotation step-length and sense of rotation to carry out the fast shaft angle degree of feedback regulation the second wave plate 10, then repeat the operation of step 3, until the result of calculation in subsequent step three meets default Δ θ error margin.

The approach that " regulates the fast shaft angle degree of the second wave plate 10 " in step 4 is expressed as to " the fast shaft angle degree of selecting suitable rotation step-length and sense of rotation to carry out feedback regulation the second wave plate 10 to the second rotating disk 3 " herein; In fact, the anglec of rotation of the second rotating disk 3 is directly corresponding to the anglec of rotation of the second wave plate 10 fast axles, and the second rotating disk 3 is by the second motor 8 driven rotary, between motor and the angular velocity of rotation of rotating disk, meet certain proportionate relationship, and this proportionate relationship is determined by the concrete gear ratio value of gearing used between motor and rotating disk, so what feedback control system 6 sent that instructions directly adjust is rotating shaft rotation step-length and the sense of rotation of the second motor 8, and this motor rotation step-length and the ratio of turntable rotation step-length just equal the ratio of both angular velocity of rotations; Due to the electric rotary commodity that can directly select in actual applications motor and rotating disk to combine, and the common proportionate relationship that has provided angular velocity of rotation between the second rotating disk 3 and the second motor 8 in the instructions of this series products, so more convenient for understanding is got up herein, the approach of " regulating the fast shaft angle degree of the second wave plate 10 " is expressed as to " the fast shaft angle degree of selecting suitable rotation step-length and sense of rotation to carry out feedback regulation the second wave plate 10 to the second rotating disk 3 ".In like manner, feedback control system 6 is when transmission instruction rotation is loaded with the first rotating disk 2 of the first wave plate 9, and what directly adjust is also the first motor 7; And in regulating device described in the utility model, the same direct anglec of rotation corresponding to the first wave plate 9 fast axles of the anglec of rotation of the first rotating disk 2, and between the first rotating disk 2 and the second rotating disk 3 and between the first motor 7 and the second motor 8, model is identical conventionally.

Wherein, the concrete theoretical analysis of step 3 is as shown below:

As shown in Figure 1, the parallel lines polarized light of polarized light source 1 outgoing is successively by after transmission axle is placed altogether the first wave plate 9, the second wave plate 10 and analyzer 4, after receiving, photodetector 5 becomes photocurrent, photocurrent data are after feedback control system 6 collection analysises, according to certain feedback control algorithm FEEDBACK CONTROL the first motor 7 and the rotation status of the second motor 8, realize fast detecting and the high precision feedback regulation of the fast axle verticality of composite wave plate.Described the first wave plate 9 and the second wave plate 10 are respectively by the first rotating disk 2 and the second rotating disk 3 clampings, fixing; The first rotating disk 2 and the second rotating disk 3 are controlled its rotation status by the first motor 7 and the second motor 8 respectively.

In the light channel structure shown in Fig. 1, the phase-delay quantity δ 2 of the phase-delay quantity δ 1 of the first wave plate 9 and the second wave plate 10 is directly provided by manufacturer conventionally, or the calculation of parameter such as the wave plate refractive index that can provide according to manufacturer and thickness draws; Actual angle between the first wave plate 9 and the fast axle of the second wave plate 10 is θ, when the fast axle of two wave plates is completely vertical, should have θ=pi/2; According to the correlation theory of polarization optics, shown in Fig. 3, in light channel structure, input represents with the Stokes of output optical signal, i.e. S _iand S _obetween pass be:

$S_o=\left(\begin{array}{cccc}A& A& 0& 0\\ A& A& 0& 0\\ 0& 0& 0& 0\\ 0& 0& 0& 0\end{array}\right)\&CenterDot;S_i=\left(\begin{array}{cccc}A& A& 0& 0\\ A& A& 0& 0\\ 0& 0& 0& 0\\ 0& 0& 0& 0\end{array}\right)\&CenterDot;\left(\begin{array}{c}{S}_{0i}\\ S_{1i}\\ S_{2i}\\ S_{3i}\end{array}\right)=\left(\begin{array}{c}A\&CenterDot;(S_{0i}+S_{1i})\\ A\&CenterDot;(S_{0i}+S_{1i})\\ 0\\ 0\end{array}\right)=\left(\begin{array}{c}{S}_0\\ S_1\\ S_2\\ S_3\end{array}\right)---\left(1\right)$

In formula (1), A is the function of α and θ, and its expression is as follows:

$\begin{array}{c}A(\mathrm{\&alpha;},\mathrm{\&theta;})=1+\frac{1}{4}[1+\cos 2\mathrm{\&alpha;}+(1-\cos 2\mathrm{\&alpha;})\&CenterDot;\cos {\mathrm{\&delta;}}_1]\&CenterDot;\{1+\cos 2(\mathrm{\&alpha;}+\mathrm{\&theta;})+[1-\cos 2(\mathrm{\&alpha;}+\mathrm{\&theta;})]\&CenterDot;\cos {\mathrm{\&delta;}}_2\}\\ +[\frac{1}{4}\&CenterDot;\sin 2\mathrm{\&alpha;}\&CenterDot;\sin 2(\mathrm{\&alpha;}+\mathrm{\&theta;})\&CenterDot;(1-\cos {\mathrm{\&delta;}}_1)\&CenterDot;(1-\cos {\mathrm{\&delta;}}_2)]+\sin \mathrm{\&alpha;}\&CenterDot;\sin (\mathrm{\&alpha;}+\mathrm{\&theta;})\&CenterDot;\sin {\mathrm{\&delta;}}_1\&CenterDot;\sin {\mathrm{\&delta;}}_2\end{array}---\left(2\right)$

In light intensity, be I _ithe situation of linearly polarized light incident under, the output photoelectric stream I of the receiving end photodetector unit of measurement mechanism described in the utility model is proportional to S in the Stokes representation of this wavelength place output optical signal ₀the light intensity of component,

$\begin{array}{c}I(\mathrm{\&alpha;},\mathrm{\&theta;})=\frac{1}{4}\&CenterDot;K\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;(S_{\mathrm{oi}}+S_{1i})\&CenterDot;A(\mathrm{\&alpha;},\mathrm{\&theta;})\\ =\frac{1}{2}\&CenterDot;K\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;{\left|E_p\right|}^2\&CenterDot;A(\mathrm{\&alpha;},\mathrm{\&theta;})\\ =\frac{K}{2}\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;I_i\&CenterDot;A(\mathrm{\&alpha;},\mathrm{\&theta;})\end{array}---\left(3\right)$

Wherein, the quantum efficiency K of photodetector 5 provides conventionally in product data, and K≤1; Ep is thoroughly the shake light amplitude of direction of analyzer 4; L is the total insertion loss of device described in the utility model, and unit is dB, and this loss value can measure.It should be noted that, for independent variable α, I (α, θ) and A (α, θ) are to be all the function of π in the cycle.Because motor and the rotating disk of any type in practical application all has certain running accuracy, the output intensity of polarized light source 1 also has certain fluctuation, even so the fast axle of the first wave plate 9 and the second wave plate 10 strict vertical (being θ=pi/2), the measured light electric current I of photodetector 5 _measure(α, θ) and its calculated value I _idealbetween (α, θ), also have certain error.In the fast axis adjustment device of existing several composite wave plates (or claiming optical axis alignment device), the source of error of photocurrent mainly contains three kinds: (i) the not strict vertical error of introducing of the fast axle of two wave plates to be aimed at; (ii) error that the running accuracy of electrical turntable is introduced, this running accuracy final decision is in the running accuracy of motor; (iii) with α and the irrelevant known fixed error of θ, be conventionally presented as the error that light source intensity fluctuation causes.In the fast axis adjustment device of composite wave plate described in the utility model, above-mentioned three kinds of photocurrent error characteristics can be analyzed in the following way: the photocurrent error while considering respectively every kind of error independent role, then obtain the root-mean-square error under all error actings in conjunction.Make a concrete analysis of as follows:

(i) the photocurrent relative error of the not strict vertical introducing of the fast axle of the first wave plate 9 and the second wave plate 10.Its expression formula is as follows:

${\mathrm{\&sigma;}}_1=\frac{\frac{\&PartialD;}{\&PartialD;\mathrm{\&theta;}}A(\mathrm{\&alpha;},\frac{\mathrm{\&pi;}}{2})\&CenterDot;\mathrm{\&Delta;\&theta;}}{A(\mathrm{\&alpha;},\frac{\mathrm{\&pi;}}{2})}---\left(4\right)$

Wherein, Δ θ be exactly photocurrent function I (α, θ) at θ=pi/2 place about the differentiate micro component of the θ that obtains of θ, the error of perpendicularity of the fast axle of two wave plates namely, and have Δ θ=θ-pi/2, and A about the partial derivative of θ is

$\begin{array}{c}\frac{\&PartialD;}{\&PartialD;\mathrm{\&theta;}}A(\mathrm{\&alpha;},\frac{\mathrm{\&pi;}}{2})=\frac{1}{2}[1+\cos 2\mathrm{\&alpha;}+(1-\cos 2\mathrm{\&alpha;})\&CenterDot;\cos {\mathrm{\&delta;}}_1]\&CenterDot;\sin 2\mathrm{\&alpha;}\&CenterDot;(1-\cos {\mathrm{\&delta;}}_2)\\ -[\frac{1}{2}\&CenterDot;\sin 2\mathrm{\&alpha;}\&CenterDot;\cos 2\mathrm{\&alpha;}\&CenterDot;(1-\cos {\mathrm{\&delta;}}_1)\&CenterDot;(1-\cos {\mathrm{\&delta;}}_2)]-{\sin }^2\mathrm{\&alpha;}\&CenterDot;\sin {\mathrm{\&delta;}}_1\&CenterDot;\sin {\mathrm{\&delta;}}_2\end{array}---(4.a)$

(ii) the photocurrent relative error that the running accuracy of the first wave plate 9 and the second wave plate 10 is introduced.Its expression formula is as follows:

${\mathrm{\&sigma;}}_2=\frac{\frac{\&PartialD;}{\&PartialD;\mathrm{\&alpha;}}A(\mathrm{\&alpha;},\frac{\mathrm{\&pi;}}{2})\&CenterDot;\mathrm{\&Delta;\&alpha;}}{A(\mathrm{\&alpha;},\frac{\mathrm{\&pi;}}{2})}---\left(5\right)$

Wherein, Δ α is the running accuracy of the first rotating disk 2 and the second rotating disk 3, and this running accuracy final decision is in the precision of the first motor 7 and the second motor 8, can calculate A about the partial derivative of α to be

$\begin{array}{c}\frac{\&PartialD;}{\&PartialD;\mathrm{\&alpha;}}A(\mathrm{\&alpha;},\frac{\mathrm{\&pi;}}{2})=\frac{1}{2}[1+\cos 2\mathrm{\&alpha;}+(1-\cos 2\mathrm{\&alpha;})\&CenterDot;\cos {\mathrm{\&delta;}}_1]\&CenterDot;\sin 2\mathrm{\&alpha;}\&CenterDot;(1-\cos {\mathrm{\&delta;}}_2)\\ +\frac{1}{2}[1-\cos 2\mathrm{\&alpha;}+(1+\cos 2\mathrm{\&alpha;})\&CenterDot;\cos {\mathrm{\&delta;}}_2]\&CenterDot;\sin 2\mathrm{\&alpha;}\&CenterDot;(\cos {\mathrm{\&delta;}}_1-1)\\ +[\frac{1}{2}\&CenterDot;\sin 4\mathrm{\&alpha;}\&CenterDot;(1-\cos {\mathrm{\&delta;}}_1)\&CenterDot;(1-\cos {\mathrm{\&delta;}}_2)]+\cos 2\mathrm{\&alpha;}\&CenterDot;\sin {\mathrm{\&delta;}}_1\&CenterDot;\sin {\mathrm{\&delta;}}_2\end{array}---(5.a)$

(iii) with α and the irrelevant known fixed error of θ.Conventionally the fixed error of device all can measure, or directly from the index instructions of related device, finds.The photocurrent relative error that the light source intensity of take fluctuation causes is example, and according to formula (3), the relative error of actual output photoelectric stream is:

${\mathrm{\&sigma;}}_F=\frac{\mathrm{\&Delta;I}}{I}=\frac{\frac{1}{2}\&CenterDot;K\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;A(\mathrm{\&alpha;},\mathrm{\&theta;})\&CenterDot;\mathrm{\&Delta;}{I}_i}{\frac{1}{2}\&CenterDot;K\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;A(\mathrm{\&alpha;},\mathrm{\&theta;})\&CenterDot;I_i}=\frac{{\mathrm{\&Delta;I}}_i}{I_i}---\left(6\right)$

Hence one can see that, and the relative error of actual output photoelectric stream always equals the relative error that light source intensity fluctuation is introduced, and generally this error can find from the index instructions of polarized light source 1, or directly measures with spectrometer.

(iv) the photocurrent total error under above-mentioned factors.The measured value I of photodetector 5 _measure(α, θ) and ideal value I _idealtotal error between (α, pi/2) is:

$\mathrm{\&sigma;}=\sqrt{{{\mathrm{\&sigma;}}_1}^2+{{\mathrm{\&sigma;}}_2}^2+{{\mathrm{\&sigma;}}_F}^2}---\left(7\right)$

When α=k π, can think

$\mathrm{\&sigma;}(\mathrm{k\&pi;},\mathrm{\&theta;})=\frac{|I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;},\frac{\mathrm{\&pi;}}{2})|}{I_{\mathrm{ideal}}(\mathrm{k\&pi;},\frac{\mathrm{\&pi;}}{2})}=\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;{\mathrm{\&Delta;\&alpha;}}^2}{{(1+\cos {\mathrm{\&delta;}}_2)}^2}}---(8.a)$

When α=k π+pi/2, can think

$\mathrm{\&sigma;}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})=\frac{|I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})|}{I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}=\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;{\left(}^{\mathrm{\&Delta;}{\mathrm{\&alpha;}}^2+{\mathrm{\&Delta;\&theta;}}^2}}{{(1+\cos {\mathrm{\&delta;}}_1)}^2}}---(8.b)$

From formula (8.a), σ (k π, θ) and Δ θ are irrelevant, so can utilize known σ _f, δ ₁, δ ₂calculate σ (k π, θ) with Δ α value, the photocurrent ideal value I while then obtaining α=k π _ideal(k π, pi/2), as shown in formula (9).

$I_{\mathrm{ideal}}(\mathrm{k\&pi;},\frac{\mathrm{\&pi;}}{2})=\left\{\begin{array}{cc}{I}_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;[1-\mathrm{\&sigma;}(\mathrm{k\&pi;},\mathrm{\&theta;})]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&GreaterEqual;I_{\mathrm{estimate}}(\mathrm{k\&pi;},\frac{\mathrm{\&pi;}}{2})\\ I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;[1+\mathrm{\&sigma;}(\mathrm{k\&pi;},\mathrm{\&theta;})]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})<I_{\mathrm{estimate}}(\mathrm{k\&pi;},\frac{\mathrm{\&pi;}}{2})\end{array}\right.---\left(9\right)$

I wherein _estimatewhen (k π, pi/2) is α=k π, the estimated value of photocurrent ideal value, its expression formula is as shown in formula (9.a).Because of parameter K, L and I wherein _iall known or can directly measure, so this estimated value can directly be calculated according to formula (9.a).

$I_{\mathrm{estimate}}(\mathrm{k\&pi;},\frac{\mathrm{\&pi;}}{2})=\frac{K}{2}\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;I_i\&CenterDot;A(\mathrm{k\&pi;},\frac{\mathrm{\&pi;}}{2})=\frac{K}{2}\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;I_i\&CenterDot;(1+\cos {\mathrm{\&delta;}}_2)---(9.a)$

Estimated value I herein _estimate(k π, pi/2) meaning is the in the situation that of taking into account system error (as light source intensity fluctuation etc.) not, the photoelectricity flow valuve only estimating according to the transport property of the characteristic parameter of each device in regulating device and whole light path, if photocurrent measured value is greater than estimated value, illustrate that measured value should be greater than ideal value I _ideal(k π, pi/2).Note having introduced being different from estimated value I herein _estimatethe photocurrent ideal value I of (k π, pi/2) _ideal(k π, pi/2), this is in order to make full use of the various known conditions in regulating device, to comprise known quantity σ _f, δ ₁, δ ₂, Δ α, K, L and I _i, k=0 especially, 1 ..., many groups photocurrent measured value I during k _measure(k π, θ) and I _measure(k π+pi/2, θ); Because in fact whole feedback regulation process is exactly the iterative computation by several times, constantly obtain I _idealthe optimization calculated value of (k π, pi/2), and then the optimization that realizes Δ θ regulates.Simultaneously according to formula (3), think photocurrent ideal value I _ideal(k π, pi/2) and I _idealbetween (k π+pi/2, pi/2), there is following relation:

$I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})=I_{\mathrm{ideal}}(\mathrm{k\&pi;},\frac{\mathrm{\&pi;}}{2})\&CenterDot;\frac{1+\cos {\mathrm{\&delta;}}_1}{1+\cos {\mathrm{\&delta;}}_2}---\left(10\right)$

Comprehensive above formula, can calculate the error of perpendicularity Δ θ of the fast axle of two wave plates:

$\mathrm{\&Delta;\&theta;}=\left\{\begin{array}{cc}\sqrt{\frac{{(1+\cos {\mathrm{\&delta;}}_1)}^2}{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2}\&CenterDot;\{{\left[\frac{I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}\right]}^2-{{\mathrm{\&sigma;}}_F}^2\}-{\mathrm{\&Delta;\&alpha;}}^2}& I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})\&GreaterEqual;I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})\\ -\sqrt{\frac{{(1+\cos {\mathrm{\&delta;}}_1)}^2}{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2}\&CenterDot;\{{\left[\frac{I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}\right]}^2-{{\mathrm{\&sigma;}}_F}^2\}-{\mathrm{\&Delta;\&alpha;}}^2}& I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})<I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})\end{array}---\left(11\right)\right.$

Wherein, desired light current value I _idealthe expression formula of (k π+pi/2, pi/2) is as follows:

$I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})=\left[\begin{array}{cc}{I}_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;\frac{1+\cos {\mathrm{\&delta;}}_1}{1+\cos {\mathrm{\&delta;}}_2}[1-\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;{\mathrm{\&Delta;\&alpha;}}^2}{{(1+\cos {\mathrm{\&delta;}}_2)}^2}}]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&GreaterEqual;\frac{K}{2}\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;I_i\&CenterDot;(1+\cos {\mathrm{\&delta;}}_2)\\ I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;\frac{1+\cos {\mathrm{\&delta;}}_1}{1+\cos {\mathrm{\&delta;}}_2}[1+\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;{\mathrm{\&Delta;\&alpha;}}^2}{{(1+\cos {\mathrm{\&delta;}}_2)}^2}}]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})<\frac{K}{2}\&CenterDot;{10}^{-\frac{\mathrm{<figure-callout\; id="10"\; label="L"\; filenames="130930155622.png"\; state="\{\{state\}\}">L</figure-callout>}}{10}}\&CenterDot;I_i\&CenterDot;(1+\cos {\mathrm{\&delta;}}_2)\end{array}\right]$

Thus, according to the size of resulting Δ θ and positive and negative, judge whether it meets the Δ θ error margin of setting; If met, feedback regulation finishes; When not meeting specification error tolerance limit, according to the size of Δ θ calculated value and positive and negative, to the second rotating disk 3, select its rotation step-length and sense of rotation to carry out the fast shaft angle degree of feedback regulation the second wave plate 10, then repeat the operation of step 3, until the result of calculation in subsequent step three meets default Δ θ error margin.Now, total phase-delay quantity δ of composite wave plate=| δ ₂-δ ₁|.

Adopt the described method of the utility model device to be actually by iterative computation repeatedly and to carry out respective feedback and regulate the optimal value that progressively approaches adjusting, i.e. θ=pi/2.Because the first wave plate 9 and the fast beam warp of the second wave plate 10 are crossed after the adjusting of step 2 substantially vertical, generally | Δ θ | 5 ° of <, so the governing speed of method is very fast described in the utility model device, and because this device has taken into full account the various factors that affects photocurrent measuring error, so degree of regulation is high, error delta θ can be adjusted to 0 in theory.

More than for the composite wave plate being comprised of two single wave plates carries out the concrete operation step that fast axle verticality regulates.For the composite wave plate being formed by a plurality of single wave plates, for example, to the achromatic waveplate being formed by which floor different polymkeric substance or the accurate alignment stack of crystal, can first regard respectively two single wave plates that form composite wave plate as the first wave plate 9 and the second wave plate 10, and adopt regulating device described in the utility model, according to above-mentioned regulating step, carry out the adjusting of fast axle verticality; Then by two single wave plate gummeds that regulate, and regard the composite wave plate having glued together as a new single wave plate, adopt regulating device described in the utility model and control method that itself and next one list wave plate to be glued together are carried out to the verticality adjusting of fast axle, and by the wave plate gummed regulating; By that analogy, again regard the composite wave plate having glued together as a new single wave plate, continue to aim at remaining single wave plate, etc.In addition, also can first several single wave plates that form composite wave plate be divided into groups, every group of two single wave plates, adopt respectively regulating device described in the utility model to regulate the fast axle of every group of list wave plate mutually vertical with control method, and by the every group of wave plate gummed regulating, for example, to the composite wave plate being formed by 5 single wave plates, can be first first and second the single wave plate grouping that form this composite wave plate be regulated and glued together, by forming the 3rd of this composite wave plate and the 4th single wave plate, divide into groups regulate and glue together, then the wave plate having glued together is regarded again as to new single wave plate, composite wave plate by the 3rd and the 4th single wave plate gummed and the 5th single wave plate are carried out to adjusting the gummed of fast axle verticality, then using this gummed wave plate as the second new wave plate 10, using the composite wave plate being glued together by first and second single wave plate as the first new wave plate 9, carry out adjusting and the gummed of fast axle verticality.

The above is preferred embodiment of the present utility model, but the utility model should not be confined to the disclosed content of this embodiment and accompanying drawing.So every, do not depart from various equivalences or the modification completing under spirit disclosed in the utility model, all within protection domain of the present utility model.

Claims (4)

1. the fast axle perpendicularity regulating device of composite wave plate, it is characterized in that: comprise polarized light source (1), feedback control system (6), the parallel lines polarized light of polarized light source (1) outgoing is successively by transmission axle is placed altogether the first rotating disk (2), the second rotating disk (3), analyzer (4), photodetector (5), the first rotating disk (2) is connected with the first motor (7), and the second rotating disk (3) is connected with the second motor (8); The same photodetector of feedback control system (6) (5), the first motor (7), the second motor (8) are connected and realize the rotation status of collection analysis photocurrent data FEEDBACK CONTROL the first motor (7) and the second motor (8); Described the first rotating disk (2) and the second rotating disk (3) are hollow structure, in described the first rotating disk (2) hollow structure, be provided with the locating device of fixing the first wave plate (9), in described the second rotating disk (3) hollow structure, be provided with the locating device of fixing the second wave plate (10).

2. the fast axle perpendicularity regulating device of a kind of composite wave plate as claimed in claim 1, is characterized in that: described feedback control system (6) is provided with calculates the first wave plate (9) and the second wave plate (10) relational expression of the error of perpendicularity Δ θ of axle soon:

$\mathrm{\&Delta;\&theta;}=\left\{\begin{array}{cc}\sqrt{\frac{{(1+\cos {\mathrm{\&delta;}}_1)}^2}{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2}\&CenterDot;\left\{\right[\frac{I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{]}^2-{{\mathrm{\&sigma;}}_F}^2\}-{\mathrm{\&Delta;\&alpha;}}^2}& I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})\&GreaterEqual;I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})\\ -\sqrt{\frac{{(1+\cos {\mathrm{\&delta;}}_1)}^2}{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2}\&CenterDot;\left\{\right[\frac{I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})-I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}{I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})}-{{\mathrm{\&sigma;}}_F}^2\}-{\mathrm{\&Delta;\&alpha;}}^2}& I_{\mathrm{measure}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\mathrm{\&theta;})<I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})\end{array}\right.$

Wherein, α is that the fast axle of the first wave plate (9) is with respect to the absolute anglec of rotation of reference position; θ is the actual angle of the first wave plate (9) and the fast between centers of the second wave plate (10); σ _ffor in regulating device with α and the irrelevant known fixed error of θ; δ 1, δ 2 are respectively the phase-delay quantity of the first wave plate (9) and the second wave plate (10); Δ α is the running accuracy of the first rotating disk (2) and the second rotating disk (3); I _measurephotocurrent data when (α, θ) is feedback control system (6) collection α=k π+pi/2, k is nonnegative integer; I _idealdesired light current value when (k π+pi/2, pi/2) is α=k π+pi/2, it is as follows that it obtains expression formula:

$I_{\mathrm{ideal}}(\mathrm{k\&pi;}+\frac{\mathrm{\&pi;}}{2},\frac{\mathrm{\&pi;}}{2})=\left\{\begin{array}{cc}{I}_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;\frac{1+\cos {\mathrm{\&delta;}}_1}{1+\cos {\mathrm{\&delta;}}_2}\&CenterDot;[1-\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;{\mathrm{\&Delta;\&alpha;}}^2}{(1+\cos {\mathrm{\&delta;}}_2{)}^2}}]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&GreaterEqual;\frac{K}{2}\&CenterDot;{10}^{-\frac{L}{10}}\&CenterDot;I_i\&CenterDot;(1+\cos {\mathrm{\&delta;}}_2)\\ I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})\&CenterDot;\frac{1+\cos {\mathrm{\&delta;}}_1}{1+\cos {\mathrm{\&delta;}}_2}\&CenterDot;[1+\sqrt{{{\mathrm{\&sigma;}}_F}^2+\frac{{\sin }^2{\mathrm{\&delta;}}_1\&CenterDot;{\sin }^2{\mathrm{\&delta;}}_2\&CenterDot;\mathrm{\&Delta;}{\mathrm{\&alpha;}}^2}{{(1+\cos {\mathrm{\&delta;}}_2)}^2}}]& I_{\mathrm{measure}}(\mathrm{k\&pi;},\mathrm{\&theta;})<\frac{K}{2}\&CenterDot;{10}^{-\frac{L}{10}}\&CenterDot;I_i\&CenterDot;(1+\cos {\mathrm{\&delta;}}_2)\end{array}\right.$

Wherein, K is the quantum efficiency of photodetector (5), insertion loss, the I that L is feedback regulation device _iinput light intensity, I for polarized light source (1) _measure(α, θ) is the photocurrent data that feedback control system (6) gathers α=k π.

3. the fast axle perpendicularity regulating device of a kind of composite wave plate as claimed in claim 1, is characterized in that: described polarized light source (1) is stable linear polarization light source or the wavelength adjustable type polarized light source of output characteristics.

4. the fast axle perpendicularity regulating device of a kind of composite wave plate as claimed in claim 1, is characterized in that: the rotation precision of described the first rotating disk (2) and the second rotating disk (3) is all less than the Δ θ error margin of setting in feedback control system (6).

Images