CN105628343A - Wave-plate detection device and method - Google Patents

Abstract

The invention discloses a wave-plate detection device, comprising a light source, a polarizing arm, a sample platform for placing a wave plate to be detected, a polarization detection arm and a detector; the centers of the polarizing arm, the wave plate to be detected and the polarization detection arm are on the same line; the light emitted by the light source is polarized and modulated by the polarizing arm to become modulation polarizing light; the modulation polarization light couples the wave plate information through the wave plate to be detected, and then the modulation and polarization detection are performed on the modulation polarization light through the polarization detection arm; and then the processed modulation polarization light is received by the detector. The invention utilizes the Mueller matrix to establish the relation between the wave plate characteristic parameter and the Mueller matrix, adopts the Mueller matrix ellipsometer to measure the Mueller matrix spectroscopic data of the wave plate to be detected so as to further obtain the characteristic parameter spectral data of the wave plate to be detected. The invention obtains the all characteristic parameter spectral data of any wave plate from one time measurement, and the parameter spectral data comprise phase retardation, a fast axis azimuth, a fast-slow axis transmittance amplitude ratio angle and a depolarization index.

Description

A kind of wave plate detecting device and method

Technical field

The invention belongs to optical element detection field, more particularly, to a kind of wave plate detecting device and method.

Background technology

Wave plate is the optical element that Optical Instrument Designing is conventional with field of optical measurements, and it enables to two vertical components of polarized light and produces additional light path (or phase contrast), and this optical path difference is called the phase-delay quantity of wave plate. The phase-delay characteristic of wave plate can be used for changing the polarization state (such as becoming circularly polarized light from line polarized light, become line polarized light etc. from elliptically polarized light) of light wave, or checks the polarization state of light wave. Wave plate is generally made by birefringece crystal, and conventional birefringece crystal includes Muscovitum, Gypsum Fibrosum, Afluon (Asta), sapphire, crystal quartz etc.

The optical characteristics of wave plate includes phase-delay quantity, phase retardation, angle of rotation, dichroism, depolarization index etc., these optical characteristics all can affect the performance of optical system, in actual use, it is necessary to the optical characteristics of wave plate is carried out detection accurately and demarcates.

At present, the detection of wave plate and calibration technique have a variety of, including interferometric method, laser frequency mode split method, phase-comparison method, phase compensation method, spectrographic method and time domain method etc. Some optical property parameter of wave plate can be carried out detection accurately and demarcate by these prior aries, but there is the deficiency of the following aspects: (1) prior art is typically only capable to characterize one or two characteristic parameter of wave plate, such as phase-delay quantity or phase retardation, and it is difficult to wave plate carries out comprehensively detection and characterizes; (2) some technology is typically only capable to provide the parameter of certain wavelength points of wave plate, then the dispersion equation of material is utilized, calculate the parameter value obtaining other wavelength, or provided the spectroscopic data of wave plate by scanning wavelength, it is also difficult in one-shot measurement, directly detect the spectrum parameter of wave plate; (3) some technology for detection precision are significantly high, and such as laser frequency mode split method the GB of detection (present retardation of wave plate be namely based on this method), but detection process and data process all complex, require higher to operator's technology.

Summary of the invention

It is an object of the invention to provide a kind of wave plate detecting device and method, the method utilizes Muller matrix to characterize wave plate optical characteristics, by setting up the equivalent model of wave plate, any wave plate is equivalent to a cascade system with the phase delay device of dichroic attenuation characteristic, a polarization apparatus and a depolarizer composition, with phase-delay quantity ��, phase retardation ��, fast and slow axis transmitance Amplitude Ration angle ��, angle of rotation �� and five parameter characterizations of depolarization index D. This invention device utilizes Muller matrix ellipsometer can provide the Muller matrix spectrum of wave plate, thus the method and device thereof can obtain all five the characteristic parameter spectrum of any wave plate in one-shot measurement, and the method and device processing ease, data process are simply.

Realizing the object of the invention and employed technical scheme comprise that a kind of wave plate detecting device, this device includes light source, is polarized arm, for placing the sample stage of wave plate to be detected, analyzing arm and detector; The described center being polarized arm, wave plate to be detected and analyzing arm is on same straight line, the light that light source sends obtains modulated polarized light after being polarized arm and being polarized and modulate, modulated polarized light is modulation and analyzing after analyzing arm after the information that wave plate to be detected couples wave plate, is finally received by a detector.

By the method that above-mentioned wave plate detecting device realizes wave plate detection, comprise the following steps:

S100, open light source, adjust and be polarized arm and analyzing arm so that it is center is on same straight line;

S200, wave plate to be detected is placed on sample stage, adjust height and the orientation of sample stage, ensure that the center of the center being put on sample stage wave plate to be detected and analyzing arm and analyzing arm is on same straight line, the beam orthogonal of light source incides wave plate to be detected, and beam and focus can all through wave plate to be detected;

S300, utilize the Muller matrix spectrum M of detector measurement wave plate to be detected_c, wave plate to be detected is at the measurement Muller matrix M that wavelength is during ��_c(��) be:

$M_c\left(\mathrm{\λ}\right)={\left[\begin{array}{cccc}1& m_{12}\left(\mathrm{\λ}\right)& m_{13}\left(\mathrm{\λ}\right)& m_{14}\left(\mathrm{\λ}\right)\\ m_{21}\left(\mathrm{\λ}\right)& m_{22}\left(\mathrm{\λ}\right)& m_{23}\left(\mathrm{\λ}\right)& m_{24}\left(\mathrm{\λ}\right)\\ m_{31}\left(\mathrm{\λ}\right)& m_{32}\left(\mathrm{\λ}\right)& m_{33}\left(\mathrm{\λ}\right)& m_{34}\left(\mathrm{\λ}\right)\\ m_{41}\left(\mathrm{\λ}\right)& m_{42}\left(\mathrm{\λ}\right)& m_{43}\left(\mathrm{\λ}\right)& m_{44}\left(\mathrm{\λ}\right)\end{array}\right]}_{\mathrm{\λ}\∈\mathrm{\Γ}}---\left(7\right)$

Wherein, �� is the spectral region of wave plate characteristic parameter to be detected, and �� is a subset in the available band scope of provided wave plate detecting device Muller matrix ellipsometer, and �� is any one wavelength points in wavelength band ��, for m_ij(��) (i=1,2,3,4; J=1,2,3,4) Muller matrix M is measured for the wave plate when wavelength is ��_c(��) normalization element;

S400, according to measuring the measurement Muller matrix M of wave plate to be detected obtained_cObtain characteristic parameter spectrum ��, �� of wave plate to be detected, ��, �� and D, �� is the phase retardation of wave plate to be detected, �� to be phase-delay quantity, �� be fast and slow axis transmitance Amplitude Ration angle �� (��), �� are angle of rotation, D is depolarization index.

Compared to existing technology, the present invention has following technical advantage:

(1) wave plate detecting device provided by the present invention and method can detect the characteristic parameter of any wave plate, including the unicast sheet of any center phase retardation of any materials, composite wave plate;

(2) wave plate detecting device provided by the present invention and method can provide all characteristic parameters of wave plate to be detected in one-shot measurement, including phase-delay quantity, phase retardation, angle of rotation, fast and slow axis transmitance reproduction ratio angle, depolarization index;

(3) wave plate detecting device provided by the present invention and method can in one-shot measurements, provide wave plate characteristic parameter phase-delay quantity to be detected, phase retardation, angle of rotation, fast and slow axis transmitance reproduction ratio angle, depolarization index spectrum, including the characteristic ginseng value of all wavelengths point in selected wavelength band.

Accompanying drawing explanation

Fig. 1 is unicast chip architecture schematic diagram.

Fig. 2 is the composite wave plate structural representation formed an angle according to optical axis by n unicast sheet.

Fig. 3 is wave plate structure of the detecting device schematic diagram proposed by the invention.

Fig. 4 is the 532nm quarter-wave quartz compound zero-th order waveplates structural representation that there is optical axis alignment error involved by the embodiment of the present invention.

Fig. 5 is the Muller matrix spectrogram of the 532nm quarter-wave quartz compound zero-th order waveplates of the existence optical axis alignment error utilizing the carried wave plate detecting device of the present invention to obtain.

Fig. 6 is the characteristic parameter spectrogram of the 532nm quarter-wave quartz compound zero-th order waveplates of the existence optical axis alignment error utilizing the carried wave plate detecting device of the present invention to obtain.

Detailed description of the invention

In order to make the purpose of the present invention, technical scheme and advantage clearly understand, below in conjunction with accompanying drawing, the present invention is further elaborated. If described herein as when relating to instantiation only in order to explain the present invention, do not limit the present invention.

In the present invention, any wave plate refers to the wave plate being become any angle to combine according to its optical axis by the single wafer of any number, and the wave plate being wherein made up of single single-chip is called unicast sheet, and the wave plate being made up of multiple single-chips is called composite wave plate.

The structural representation of single wave plate is as it is shown in figure 1, light is propagated along z-axis negative direction, and wave plate placement parallel with x-o-y plane, the angle theta between fast axle (F) and the x of wave plate is called the phase retardation of wave plate. Multiple unicast sheets combine according to optical axis is at a certain angle, are called composite wave plate, as shown in Figure 2, light is propagated along z-axis negative direction, according to the light direction of propagation, each unicast sheet of any composite wave plate is called wave plate 1, wave plate 2 ..., wave plate n, and the fast axle of each unicast sheet is expressed as F₁��F₂������F₃, ��₁����₂��������₃The respectively angle between fast axle and the x-axis of each unicast sheet, is called the phase retardation of each unicast sheet.

In the present invention, wave plate Muller matrix is expressed as:

$M=\left[\begin{array}{cccc}{M}_{11}& M_{12}& M_{13}& M_{14}\\ M_{21}& M_{22}& M_{23}& M_{24}\\ M_{31}& M_{32}& M_{33}& M_{34}\\ M_{41}& M_{42}& M_{43}& M_{44}\end{array}\right]=M_{11}\left[\begin{array}{cccc}1& m_{12}& m_{13}& m_{14}\\ m_{21}& m_{22}& m_{23}& m_{24}\\ m_{31}& m_{32}& m_{33}& m_{34}\\ m_{41}& m_{42}& m_{43}& m_{44}\end{array}\right]---\left(1\right)$

Wherein M is the Muller matrix of wave plate, M_ij(i=1,2,3,4; J=1,2,3,4) for 16 non-normalized elements of wave plate Muller matrix, m_ij(i=1,2,3,4; J=1,2,3,4) for wave plate Muller matrix relative to M₁₁Normalized Muller matrix element.

As present invention further optimization, the Muller matrix with the phase delay device of dichroic attenuation characteristic, polarization apparatus and depolarizer can be expressed as

$\begin{array}{c}M(\mathrm{\θ},\mathrm{\δ},\mathrm{\ψ})=R(-\mathrm{\θ})M(\mathrm{\δ},\mathrm{\ψ})R\left(\mathrm{\θ}\right)\\ \left[\begin{array}{cccc}1& 0& 0& 0\\ 0& \cos 2\mathrm{\θ}& -\sin 2\mathrm{\θ}& 0\\ 0& \sin 2\mathrm{\θ}& \cos 2\mathrm{\θ}& 0\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{cccc}1& -\cos 2\mathrm{\ψ}& 0& 0\\ -\cos 2\mathrm{\ψ}& 1& 0& 0\\ 0& 0& \sin 2\mathrm{\ψ}\cos \mathrm{\δ}& \sin 2\mathrm{\ψ}\sin \mathrm{\δ}\\ 0& 0& -\sin 2\mathrm{\ψ}\sin \mathrm{\δ}& \sin 2\mathrm{\ψ}\cos \mathrm{\δ}\end{array}\right]\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& \cos 2\mathrm{\θ}& \sin 2\mathrm{\θ}& 0\\ 0& -\sin 2\mathrm{\θ}& \cos 2\mathrm{\θ}& 0\\ 0& 0& 0& 1\end{array}\right]\end{array}---\left(2\right)$

$R\left(\mathrm{\ρ}\right)=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& \cos 2\mathrm{\ρ}& \sin 2\mathrm{\ρ}& 0\\ 0& -\sin 2\mathrm{\ρ}& \cos 2\mathrm{\ρ}& 0\\ 0& 0& 0& 1\end{array}\right]---\left(3\right)$

$M\left(D\right)=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& d_a& 0& 0\\ 0& 0& d_b& 0\\ 0& 0& 0& d_c\end{array}\right]---\left(4\right)$

Wherein, M (��, ��, ��), R (��) and M (D) respectively there is the Muller matrix of the phase delay device of dichroic attenuation characteristic, polarization apparatus, depolarizer, �� is the phase retardation of phase delay device, and �� is the phase-delay quantity of phase delay device, �� is the fast and slow axis transmitance Amplitude Ration angle of phase delay device, �� is the angle of rotation of polarization apparatus, and D is the depolarization index of depolarizer, and wherein D can by a point depolarization index d_a��d_bAnd d_cCalculating obtains,

$D=1-\frac{\left|d_a\right|+\left|d_c\right|+\left|d_c\right|}{3}---\left(5\right)$

The equivalent model of any wave plate Muller matrix form describes

M=R (��) R (-��) M (��, ��) R (��) M (D) (6)

Wherein, M is the Muller matrix of any wave plate, and M (��, ��, ��), R (��) and M (D) respectively have the Muller matrix of the phase delay device of dichroic attenuation characteristic, polarization apparatus, depolarizer.

The optical characteristics of any wave plate can represent with a Muller matrix as shown in formula (1). Ideally, become the composite wave plate that certain optical axis included angle forms optically can be equivalent to an optical phase delay device and a polarization apparatus by multiple unicast sheets according to optical axis, represent with phase-delay quantity, phase retardation and three characteristic parameters of angle of rotation. Under practical situation, wave plate can produce certain dichroic attenuation characteristic and depolarization characteristic due to the factor such as fault in material, manufacturing deficiency, now, one actual composite wave plate can be equivalent to one and have the phase delay device of dichroic attenuation characteristic, a polarization apparatus and a depolarizer, with phase-delay quantity ��, phase retardation ��, fast and slow axis transmitance Amplitude Ration angle ��, angle of rotation �� and five parameter characterizations of depolarization index D, as shown in formula (6). Wave plate detection method provided by the present invention is based on the above-mentioned wave plate principle of equal effects.

Wave plate detecting device of the present invention is Muller matrix ellipsometer, as shown in Figure 3, this Muller matrix ellipsometer includes a light source 1, and is polarized arm PSG2,3, analyzing arm PSA4 of a sample stage, a detector 5, wherein wave plate 6 to be detected is placed on sample stage, wherein sample stage 3 can move up and down and horizontally rotate to adjust height and the orientation of wave plate 6 to be measured, is polarized arm PSG2 and analyzing arm PSA4 and can adjust angle so that light beam can with wave plate 6 to be detected on different incident angles to sample stage 3. it is polarized arm PSG2, wave plate 6 to be detected, the center of analyzing arm PSA4 three is on same straight line, the light that light source 1 sends is called modulated polarized light after being polarized arm PSG2 and being polarized and modulate, modulated polarized light is through wave plate to be detected, there is certain change in the polarization state of polarized light, thus having coupled the information of wave plate, after being then passed through analyzing arm PSA4, polarized light is modulated and analyzing further, finally received by detector 5, the signal that detector 5 is received carries out processing the Muller matrix that can obtain wave plate 6 to be detected, all characteristic parameters of wave plate are obtained further with wave plate detection method provided by the present invention.

The detection process realizing any wave plate all characteristic parameters obtaining wave plate are implemented in accordance with the following steps:

S100, open the light source of wave plate detecting device Muller matrix ellipsometer provided by the present invention, what adjust Muller matrix ellipsometer is polarized arm PSG and analyzing arm PSA, Shi Qi center is on same straight line, ensureing that the light beam sent from light source can sequentially pass through and be polarized arm PSG and analyzing arm PSA, the light intensity signal that detector receives reaches the strongest.

S200, wave plate to be detected is placed on the sample stage of Muller matrix ellipsometer, adjust height of specimen and orientation, the center of guarantee wave plate and the center of Muller matrix ellipsometer analyzing arm PSG and analyzing arm PSA are on same straight line, beam orthogonal incides wave plate to be detected, and beam and focus can all through wave plate to be detected.

S300, utilize the Muller matrix spectrum M of the Muller matrix ellipsometer measurement wave plate to be detected of wave plate detecting device provided by the present invention_c, wave plate to be detected is at the measurement Muller matrix M that wavelength is during ��_c(��) be:

$M_c\left(\mathrm{\λ}\right)={\left[\begin{array}{cccc}1& m_{12}\left(\mathrm{\λ}\right)& m_{13}\left(\mathrm{\λ}\right)& m_{14}\left(\mathrm{\λ}\right)\\ m_{21}\left(\mathrm{\λ}\right)& m_{22}\left(\mathrm{\λ}\right)& m_{23}\left(\mathrm{\λ}\right)& m_{24}\left(\mathrm{\λ}\right)\\ m_{31}\left(\mathrm{\λ}\right)& m_{32}\left(\mathrm{\λ}\right)& m_{33}\left(\mathrm{\λ}\right)& m_{34}\left(\mathrm{\λ}\right)\\ m_{41}\left(\mathrm{\λ}\right)& m_{42}\left(\mathrm{\λ}\right)& m_{43}\left(\mathrm{\λ}\right)& m_{44}\left(\mathrm{\λ}\right)\end{array}\right]}_{\mathrm{\λ}\∈\mathrm{\Γ}}---\left(7\right)$

Wherein, �� is the spectral region of wave plate characteristic parameter to be detected, and �� is a subset in the available band scope of provided wave plate detecting device Muller matrix ellipsometer, and �� is any one wavelength points in wavelength band ��, for m_ij(��) (i=1,2,3,4; J=1,2,3,4) Muller matrix M is measured for the wave plate when wavelength is ��_c(��) normalization element.

S400, the wave plate to be detected obtained according to Muller matrix ellipsometer measurement measurement Muller matrix M_cObtain the characteristic parameter spectrum (��, ��, ��, ��, D) of wave plate to be detected, specifically can carry out according to following steps.

S401, it is that Muller matrix M measured by wave plate during �� according to wavelength_c(��), it is the depolarization index D (��) during �� that calculating obtains wave plate to be detected at wavelength, as follows

$D\left(\mathrm{\λ}\right)=1-{\left\{\frac{Tr\[M_c\left(\mathrm{\λ}\right)M_c^T\left(\mathrm{\λ}\right)\]-1}{3}\right\}}^{1/2}---\left(8\right)$

Wherein, the mark of Tr representing matrix, the transposition of T representing matrix.

S402, it is that Muller matrix M measured by wave plate during �� according to wavelength_c(��) wave plate to be detected obtained with step 1 is the depolarization index D (��) during �� at wavelength, calculates wave plate to be detected and does not comprise the Muller matrix M of depolarization parameter_c' (��), can be obtained by following formula

$M_c^{\′}\left(\mathrm{\λ}\right)=M_c\left(\mathrm{\λ}\right)M^{-1}\[D\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& m_{12}^{\′}\left(\mathrm{\λ}\right)& m_{13}^{\′}\left(\mathrm{\λ}\right)& m_{14}^{\′}\left(\mathrm{\λ}\right)\\ m_{21}^{\′}\left(\mathrm{\λ}\right)& m_{22}^{\′}\left(\mathrm{\λ}\right)& m_{23}^{\′}\left(\mathrm{\λ}\right)& m_{24}^{\′}\left(\mathrm{\λ}\right)\\ m_{31}^{\′}\left(\mathrm{\λ}\right)& m_{32}^{\′}\left(\mathrm{\λ}\right)& m_{33}^{\′}\left(\mathrm{\λ}\right)& m_{34}^{\′}\left(\mathrm{\λ}\right)\\ m_{41}^{\′}\left(\mathrm{\λ}\right)& m_{42}^{\′}\left(\mathrm{\λ}\right)& m_{43}^{\′}\left(\mathrm{\λ}\right)& m_{44}^{\′}\left(\mathrm{\λ}\right)\end{array}\right]---\left(9\right)$

Wherein, M^-1[D (��)] represents the inverse matrix that depolarization index is D (��) depolarizer Muller matrix, m_ij' (��) (i=1,2,3,4; J=1,2,3,4) represent that wave plate to be detected does not comprise the Muller matrix M of depolarization parameter_c' the normalization element of (��).

S403, obtain wave plate to be detected when wavelength is �� according to step 2 and do not comprise the Muller matrix M of depolarization parameter_c' (��), calculate and obtain the phase retardation �� (��) of the wave plate to be detected wave plate to be detected when wavelength is ��, phase-delay quantity �� (��), fast and slow axis transmitance Amplitude Ration angle �� (��), angle of rotation �� (��). Now there is following relation

M_c' (��)=R [�� (��)] R [-�� (��)] M [�� (��), �� (��)] R [�� (��)] (10)

Wherein, R [�� (��)], R [-�� (��)], R [�� (��)] and M [�� (��), �� (��)] has respectively is form as follows

$R\[\mathrm{\ρ}\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& \cos 2\mathrm{\ρ}\left(\mathrm{\λ}\right)& \sin 2\mathrm{\ρ}\left(\mathrm{\λ}\right)& 0\\ 0& -\sin 2\mathrm{\ρ}\left(\mathrm{\λ}\right)& \cos 2\mathrm{\ρ}\left(\mathrm{\λ}\right)& 0\\ 0& 0& 0& 1\end{array}\right]---\left(11\right)$

$R\[-\mathrm{\θ}\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& \cos 2\mathrm{\θ}\left(\mathrm{\λ}\right)& -\sin 2\mathrm{\θ}\left(\mathrm{\λ}\right)& 0\\ 0& \sin 2\mathrm{\θ}\left(\mathrm{\λ}\right)& \cos 2\mathrm{\θ}\left(\mathrm{\λ}\right)& 0\\ 0& 0& 0& 1\end{array}\right]---\left(12\right)$

$R\[\mathrm{\θ}\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& \cos 2\mathrm{\θ}\left(\mathrm{\λ}\right)& \sin 2\mathrm{\θ}\left(\mathrm{\λ}\right)& 0\\ 0& -\sin 2\mathrm{\θ}\left(\mathrm{\λ}\right)& \cos 2\mathrm{\θ}\left(\mathrm{\λ}\right)& 0\\ 0& 0& 0& 1\end{array}\right]---\left(13\right)$

$M\[\mathrm{\δ}\left(\mathrm{\λ}\right),\mathrm{\ψ}\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& -\cos 2\mathrm{\ψ}\left(\mathrm{\λ}\right)& 0& 0\\ -\cos 2\mathrm{\ψ}\left(\mathrm{\λ}\right)& 1& 0& 0\\ 0& 0& \sin 2\mathrm{\ψ}\left(\mathrm{\λ}\right)\cos \mathrm{\δ}\left(\mathrm{\λ}\right)& \sin 2\mathrm{\ψ}\left(\mathrm{\λ}\right)\sin \mathrm{\δ}\left(\mathrm{\λ}\right)\\ 0& 0& -\sin 2\mathrm{\ψ}\left(\mathrm{\λ}\right)\sin \mathrm{\δ}\left(\mathrm{\λ}\right)& \sin 2\mathrm{\ψ}\left(\mathrm{\λ}\right)\cos \mathrm{\δ}\left(\mathrm{\λ}\right)\end{array}\right]---\left(14\right)$

Simultaneous formula (9)-(14) can obtain the phase retardation �� (��) of the wave plate to be detected when wavelength is �� of wave plate to be detected, phase-delay quantity �� (��), fast and slow axis transmitance Amplitude Ration angle �� (��), angle of rotation �� (��).

S404, conversion wavelength, repeat step S401��S403, obtain the phase retardation �� (��) of wave plate to be detected under another one wavelength, phase-delay quantity �� (��), fast and slow axis transmitance Amplitude Ration angle �� (��), angle of rotation �� (��) and depolarization index D (��).

S405, constantly repetition step S404, until the phase retardation of wave plate to be detected, phase-delay quantity, fast and slow axis transmitance Amplitude Ration angle, angle of rotation and depolarization index under all wavelengths in selected wavelength band ��, obtain all characteristic parameter spectrum of wave plate to be detected.

In the present embodiment, illustrate the implementation process of wave plate detection method provided by the present invention and device with a homemade Muller matrix ellipsometer, but wave plate detection method provided by the present invention and device thereof are not limited thereto. The usable wavelength range of the self-control Muller matrix ellipsometer in the embodiment of the present invention is 200-1000nm.

In order to further explain implementation process and effect of wave plate detection method provided by the present invention and device thereof, there is the 532nm quarter-wave quartz compound zero-th order waveplates of certain alignment error for wave plate to be detected with optical axis in above-described embodiment. As shown in Figure 4, this composite wave plate comprises two unicast sheets, and respectively at the parallel placement of x-o-y plane, light is propagated along z-axis negative direction, and according to the light direction of propagation, two unicast sheets are called wave plate 1, wave plate 2, and its fast axle is expressed as F₁��F₂, ��₁����₂Respectively the angle between fast axle and the x-axis of two unicast sheets, is called its phase retardation, S₁For the slow axis of wave plate 1, the fast axle of unicast sheet and slow axis are orthogonal, therefore F₁��S₁. Compound zero-th order waveplates to ideal design, is mutually perpendicular between fast axle and the fast axle of wave plate 1 of wave plate 2, therefore has F₁��F₂Or F₂��S₁. In actual processing, between the fast axle of two wave plates will not desired vertical, can there is certain alignment error ��, therefore F₂And S₁Between angle be ��. This alignment error can make certain fluctuation occur in the parameter spectrum such as the phase-delay quantity of composite wave plate, phase retardation and angle of rotation.

The wave plate detection method of the present embodiment and the operating procedure of device thereof are described in detail below in conjunction with specific implementation process:

(1) light source of wave plate detecting device Muller matrix ellipsometer provided by the present invention is opened, what adjust Muller matrix ellipsometer is polarized arm PSG and analyzing arm PSA, Muller matrix ellipsometer is made to be in straight-through measurement pattern, namely the center of arm PSG and analyzing arm PSA that is polarized is on same straight line, ensureing that the light beam sent from light source can sequentially pass through and be polarized arm PSG and analyzing arm PSA, the light intensity signal that detector receives reaches the strongest.

(2) quartz compound zero-th order waveplates to be detected is placed on the sample stage of Muller matrix ellipsometer, adjust height of specimen and orientation, the center of guarantee wave plate and the center of Muller matrix ellipsometer analyzing arm PSG and analyzing arm PSA are on same straight line, beam orthogonal incides wave plate to be detected, and beam and focus can all through wave plate to be detected.

(3) the Muller matrix spectrum M of the Muller matrix ellipsometer measurement wave plate to be detected of wave plate detecting device provided by the present invention is utilized_c, wherein, wavelength detecting wavelength �� elects the spectral range available of this self-control Muller matrix ellipsometer as, i.e. ��=[200nm, 1000nm], and the Muller matrix spectroscopic data of this embodiment 532nm quarter-wave quartz compound zero-th order waveplates is as shown in Figure 5.

(4) the measurement Muller matrix M of the wave plate to be detected obtained according to Muller matrix ellipsometer measurement_cCharacteristic parameter spectrum (�� with the process acquisition wave plate to be detected that formula (8)-(14) are shown, ��, ��, ��, D), the characteristic parameter spectroscopic data of this embodiment 532nm quarter-wave quartz compound zero-th order waveplates as shown in Figure 6, including phase-delay quantity, phase retardation, angle of rotation, fast and slow axis transmitance Amplitude Ration angle, depolarization index.

By above example, visible wave plate detection method provided by the present invention and device thereof can provide whole characteristic parameter spectroscopic datas of wave plate in one-shot measurement, including phase-delay quantity, phase retardation, angle of rotation, fast and slow axis transmitance Amplitude Ration angle, depolarization index, this is that existing wave plate detection technique is difficult to.

Only optical axis is existed for usable wavelength range for the self-control Muller matrix ellipsometer of 200-1000nm the detection process of the 532nm quarter-wave quartz compound zero-th order waveplates of certain alignment error above when describing concrete implementation process, but the present invention is not only limited to above-mentioned detailed description of the invention, persons skilled in the art are according to method for designing disclosed by the invention, other multiple detailed description of the invention can be adopted to implement the present invention, as selected different Muller matrix ellipsometers, different wave plates to be detected etc., therefore, the wave plate detection method of every employing present invention and the thinking of device thereof, do some designs simply changing or changing, both fall within the scope of protection of the invention.

Claims (4)

1. a wave plate detecting device, it is characterised in that: include light source, be polarized arm, for placing the sample stage of wave plate to be detected, analyzing arm and detector; The described center being polarized arm, wave plate to be detected and analyzing arm is on same straight line, the light that light source sends obtains modulated polarized light after being polarized arm and being polarized and modulate, modulated polarized light is modulation and analyzing after analyzing arm after the information that wave plate to be detected couples wave plate, is finally received by a detector.

2. wave plate detecting device according to claim 1, it is characterised in that: described sample stage is provided with and moves up and down governor motion and horizontally rotate governor motion.

3. the method realizing wave plate detection by wave plate detecting device described in claim 1, it is characterised in that including:

S100, open light source, adjust and be polarized arm and analyzing arm so that it is center is on same straight line;

S200, wave plate to be detected is placed on sample stage, adjust height and the orientation of sample stage, ensure that the center of the center being put on sample stage wave plate to be detected and analyzing arm and analyzing arm is on same straight line, the beam orthogonal of light source incides wave plate to be detected, and beam and focus can all through wave plate to be detected;

S300, utilize the Muller matrix spectrum M of detector measurement wave plate to be detected_c, wave plate to be detected is at the measurement Muller matrix M that wavelength is during ��_c(��) be:

$M_c\left(\mathrm{\λ}\right)={\left[\begin{array}{cccc}1& m_{12}\left(\mathrm{\λ}\right)& m_{13}\left(\mathrm{\λ}\right)& m_{14}\left(\mathrm{\λ}\right)\\ m_{21}\left(\mathrm{\λ}\right)& m_{22}\left(\mathrm{\λ}\right)& m_{23}\left(\mathrm{\λ}\right)& m_{24}\left(\mathrm{\λ}\right)\\ m_{31}\left(\mathrm{\λ}\right)& m_{32}\left(\mathrm{\λ}\right)& m_{33}\left(\mathrm{\λ}\right)& m_{34}\left(\mathrm{\λ}\right)\\ m_{41}\left(\mathrm{\λ}\right)& m_{42}\left(\mathrm{\λ}\right)& m_{43}\left(\mathrm{\λ}\right)& m_{44}\left(\mathrm{\λ}\right)\end{array}\right]}_{\mathrm{\λ}\∈\mathrm{\Γ}}---\left(7\right)$

Wherein, �� is the spectral region of wave plate characteristic parameter to be detected, and �� is a subset in the available band scope of provided wave plate detecting device Muller matrix ellipsometer, and �� is any one wavelength points in wavelength band ��, for m_ij(��) (i=1,2,3,4; J=1,2,3,4) Muller matrix M is measured for the wave plate when wavelength is ��_c(��) normalization element;

S400, according to measuring the measurement Muller matrix M of wave plate to be detected obtained_cObtain characteristic parameter spectrum ��, �� of wave plate to be detected, ��, �� and D, �� is the phase retardation of wave plate to be detected, �� to be phase-delay quantity, �� be fast and slow axis transmitance Amplitude Ration angle �� (��), �� are angle of rotation, D is depolarization index.

4. the method realizing wave plate detection according to claim 3, it is characterised in that described step S400 includes:

S401, it is that Muller matrix M measured by wave plate during �� according to wavelength_c(��), it is the depolarization index D (��) during �� that calculating obtains wave plate to be detected at wavelength, as follows

$D\left(\mathrm{\λ}\right)=1-{\left\{\frac{Tr\[M_c\left(\mathrm{\λ}\right)M_c^T\left(\mathrm{\λ}\right)\]-1}{3}\right\}}^{1/2}---\left(8\right)$

Wherein, the mark of Tr representing matrix, the transposition of T representing matrix;

S402, it is that Muller matrix M measured by wave plate during �� according to wavelength_c(��) wave plate to be detected obtained with step S401 is the depolarization index D (��) during �� at wavelength, calculates wave plate to be detected and does not comprise the Muller matrix M of depolarization parameter_c' (��), can be obtained by following formula

$M_c^{\′}\left(\mathrm{\λ}\right)=M_c\left(\mathrm{\λ}\right)M^{-1}\[D\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& m_{12}^{\′}\left(\mathrm{\λ}\right)& m_{13}^{\′}\left(\mathrm{\λ}\right)& m_{14}^{\′}\left(\mathrm{\λ}\right)\\ m_{21}^{\′}\left(\mathrm{\λ}\right)& m_{22}^{\′}\left(\mathrm{\λ}\right)& m_{23}^{\′}\left(\mathrm{\λ}\right)& m_{24}^{\′}\left(\mathrm{\λ}\right)\\ m_{31}^{\′}\left(\mathrm{\λ}\right)& m_{32}^{\′}\left(\mathrm{\λ}\right)& m_{33}^{\′}\left(\mathrm{\λ}\right)& m_{34}^{\′}\left(\mathrm{\λ}\right)\\ m_{41}^{\′}\left(\mathrm{\λ}\right)& m_{42}^{\′}\left(\mathrm{\λ}\right)& m_{43}^{\′}\left(\mathrm{\λ}\right)& m_{44}^{\′}\left(\mathrm{\λ}\right)\end{array}\right]---\left(9\right)$

Wherein, M^-1[D (��)] represents the inverse matrix that depolarization index is D (��) depolarizer Muller matrix, m_ij' (��) (i=1,2,3,4; J=1,2,3,4) represent that wave plate to be detected does not comprise the Muller matrix M of depolarization parameter_c' the normalization element of (��);

S403, obtain wave plate to be detected when wavelength is �� according to step S402 and do not comprise the Muller matrix M of depolarization parameter_c' (��), calculate and obtain the phase retardation �� (��) of the wave plate to be detected wave plate to be detected when wavelength is ��, phase-delay quantity �� (��), fast and slow axis transmitance Amplitude Ration angle �� (��), angle of rotation �� (��), now have following relation

M��_c(��)=R [�� (��)] R [-�� (��)] M [�� (��), �� (��)] R [�� (��)] (10)

Wherein, R [�� (��)], R [-�� (��)], R [�� (��)] and M [�� (��), �� (��)] has respectively is form as follows

$R\[\mathrm{\ρ}\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& cos2\mathrm{\ρ}\left(\mathrm{\λ}\right)& \sin 2\mathrm{\ρ}\left(\mathrm{\λ}\right)& 0\\ 0& -\sin 2\mathrm{\ρ}\left(\mathrm{\λ}\right)& cos2\mathrm{\ρ}\left(\mathrm{\λ}\right)& 0\\ 0& 0& 0& 1\end{array}\right]---\left(11\right)$

$R\[-\mathrm{\θ}\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& cos2\mathrm{\θ}\left(\mathrm{\λ}\right)& -\sin 2\mathrm{\θ}\left(\mathrm{\λ}\right)& 0\\ 0& \sin 2\mathrm{\θ}\left(\mathrm{\λ}\right)& \cos 2\mathrm{\θ}\left(\mathrm{\λ}\right)& 0\\ 0& 0& 0& 1\end{array}\right]---\left(12\right)$

$R\[\mathrm{\θ}\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& cos2\mathrm{\θ}\left(\mathrm{\λ}\right)& \sin 2\mathrm{\θ}\left(\mathrm{\λ}\right)& 0\\ 0& -sin2\mathrm{\θ}\left(\mathrm{\λ}\right)& cos2\mathrm{\θ}\left(\mathrm{\λ}\right)& 0\\ 0& 0& 0& 1\end{array}\right]---\left(13\right)$

$M\[\mathrm{\δ}\left(\mathrm{\λ}\right),\mathrm{\ψ}\left(\mathrm{\λ}\right)\]=\left[\begin{array}{cccc}1& -\cos 2\mathrm{\ψ}\left(\mathrm{\λ}\right)& 0& 0\\ -\cos 2\mathrm{\ψ}\left(\mathrm{\λ}\right)& 1& 0& 0\\ 0& 0& \sin 2\mathrm{\ψ}\left(\mathrm{\λ}\right)\cos \mathrm{\δ}\left(\mathrm{\λ}\right)& \sin 2\mathrm{\ψ}\left(\mathrm{\λ}\right)\sin \mathrm{\δ}\left(\mathrm{\λ}\right)\\ 0& 0& -\sin 2\mathrm{\ψ}\left(\mathrm{\λ}\right)\sin \mathrm{\δ}\left(\mathrm{\λ}\right)& \sin 2\mathrm{\ψ}\left(\mathrm{\λ}\right)\cos \mathrm{\δ}\left(\mathrm{\λ}\right)\end{array}\right]---\left(14\right)$

Simultaneous formula (9)-(14) can obtain the phase retardation �� (��) of the wave plate to be detected when wavelength is �� of wave plate to be detected, phase-delay quantity �� (��), fast and slow axis transmitance Amplitude Ration angle �� (��), angle of rotation �� (��);

S404, conversion wavelength, repeat step S401-S403, obtain the phase retardation �� (��) of wave plate to be detected under another one wavelength, phase-delay quantity �� (��), fast and slow axis transmitance Amplitude Ration angle �� (��), angle of rotation �� (��) and depolarization index D (��);

S405, constantly repetition step S404, until the phase retardation of wave plate to be detected, phase-delay quantity, fast and slow axis transmitance Amplitude Ration angle, angle of rotation and depolarization index under all wavelengths in selected wavelength band ��, obtain all characteristic parameter spectrum of wave plate to be detected.