Spectroscopic polarimetry

Abstract

In the channeled spectroscopic polarimetry, a measurement error of a parameter showing a spectropolarization characteristic of a sample is effectively removed, the error being generated by various variations in retardation of a retarder depending upon the state of the sample. With attention being focused on that the retardation of the retarder may be kept constant by stabilization of an incident direction of light that transmits through the retarder, the retarder was arranged on the light source side with respect to the sample so as to effectively remove an influence relative to a measurement error, such as variations in direction of a light ray due to the sample.

1 . A spectroscopic polarimetry, comprising the steps of: 
 preparing an object to be measured;    preparing a polarimetric spectroscope which includes    a projection optical system, comprising a light source, a polarizer and a plurality of retarders, where the light source, the polarizer and the plurality of retarders are arranged such that light emitted from the light source is irradiated on the object to be measured after passing through the polarizer and the plurality of retarders in this order,    an analyzer for allowing light to transmit therethrough, the light having been emitted from the projection optical system and reflected on or transmitted through the object to be measured, and    a device for obtaining the spectral intensity of the light having transmitted through the analyzer; and    obtaining the spectral intensity of the object to be measured by use of the polarimetric spectroscope.    
   
   
       2 . The spectroscopic polarimetry according to  claim 1 , further comprising a step of obtaining at least one of spectropolarization parameters of the object to be measured by use of the obtained spectral intensity.  
   
   
       3 . The spectroscopic polarimetry according to  claim 2 , wherein 
 the plurality of retarders that the projection optical system comprises are a first retarder and a second retarder, and    the light source, the polarizer, the first retarder and the second retarder are arranged such that light emitted from the light source transmits through the polarizer, the second retarder and the first retarder in this order, the orientation of a transmission axis of the polarizer disagrees with the orientation of a principal axis of the second retarder, and the orientation of the principal axis of the second retarder disagrees with the orientation of a principal axis of the first retarder.    
   
   
       4 . The spectroscopic polarimetry according to  claim 3 , wherein the step of obtaining at least one of spectropolarization parameters is a step which comprises: 
 obtaining, from the spectral intensity, a spectral intensity component (first spectral intensity component) which nonperiodically vibrates with wavenumber and a spectral intensity component (third spectral intensity component) which vibrates at a frequency depending upon a retardation (φ 2 (σ)) of the second retarder and not depending upon a retardation (φ 1 (σ)) of the first retarder, with wavenumber; and    obtaining at least one of spectropolarization parameters by use of each of the spectral intensity components.    
   
   
       5 . The spectroscopic polarimetry according to  claim 3 , wherein the step of obtaining at least one of spectropolarization parameters is a step which comprises: 
 obtaining, from the spectral intensity, at least one of a spectral intensity component (second spectral intensity component) which vibrates at a frequency depending upon a variation between the retardation (φ 1  (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder with wavenumber, a spectral intensity component (fourth spectral intensity component) which vibrates at a frequency depending upon the sum of the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder with wavenumber, and a spectral intensity component (fifth spectral intensity component) which vibrates at a frequency depending upon the retardation (φ 1 (σ)) of the first retarder and not depending upon the retardation (φ 2 (σ)) of the second retarder, with wavenumber; and    obtaining at least one of the spectropolarization parameters of the object to be measured by use of the obtained spectral intensity component.    
   
   
       6 . The spectroscopic polarimetry according to  claim 3 , wherein the step of obtaining at least one of spectropolarization parameters is a step which comprises: 
 obtaining, from the spectral intensity,    at least one of the spectral intensity component (first spectral intensity component) which nonperiodically vibrates with wavenumber and the spectral intensity component (third spectral intensity component) which vibrates at a frequency depending upon the retardation (φ 2 (σ)) of the second retarder and not depending upon the retardation (φ 1 (σ)) of the first retarder, with wavenumber, and    at least one of the spectral intensity component (second spectral intensity component) which vibrates at a frequency depending upon the difference between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder with wavenumber, the spectral intensity component (fourth spectral intensity component) which vibrates at a frequency depending upon the sum of the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder with wavenumber, and the spectral intensity component (fifth spectral intensity component) which vibrates at a frequency depending upon the retardation (φ 1 (σ)) of the first retarder and not depending upon the retardation (φ 2 (σ)) of the second retarder, with wavenumber; and    obtaining at least one of the spectropolarization parameters of the object to be measured by use of each of the obtained spectral intensity components.    
   
   
       7 . The spectroscopic polarimetry according to  claim 3 , wherein the step of obtaining at least one of spectropolarization parameters is a step which comprises: 
 obtaining the retardation (φ 2 (σ)) of the second retarder from the spectral intensity; and    obtaining at least one of the spectropolarization parameters of the object to be measured by use of the spectral intensity and the retardation (φ 2 (σ)) of the second retarder.    
   
   
       8 . The spectroscopic polarimetry according to  claim 3 , further comprising a step of acquiring data showing the relation between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder, wherein the step of obtaining at least one of spectropolarization parameters is a step which comprises: 
 obtaining the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder from the spectral intensity and the data showing the relation between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder; and    obtaining at least one of the spectropolarization parameters of the object to be measured by use of the spectral intensity, the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder.    
   
   
       9 . The spectroscopic polarimetry according to  claim 3 , further comprising the steps of: 
 acquiring data showing the relation between the retardation variation (Δφ 1 (σ)) of the first retarder and the retardation variation (Δφ 2 (σ)) of the second retarder; and    acquiring a reference value (φ 1   (i) (σ)) for calibration of retardation of the first retarder and a reference value (φ 2   (i) (σ)) for calibration of retardation of the second retarder,    wherein the step of obtaining at least one of spectropolarization parameters is a step which comprises:    obtaining, from the spectral intensity, the retardation (φ 2 (σ)) of the second retarder and the retardation variation (Δφ 2 (σ)) of the second retarder from the reference value (φ 2   (i) (σ)) for calibration;    obtaining the retardation variation (Δφ 1 (σ)) of the first retarder by use of the obtained retardation variation (Δφ 2 (σ)) of the second retarder and data showing the relation between the retardation variation (Δφ 1 (σ)) of the first retarder and the retardation variation (Δφ 2 (σ)) of the second retarder;    obtaining the retardation (φ 1 (σ)) of the first retarder from a reference value (φ 1   (i) (σ)) for calibration of retardation of the first retarder and the obtained retardation variation (Δφ 1 (σ)) of the first retarder; and    obtaining at least one of the spectropolarization parameters of the object to be measured by use of the spectral intensity, the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder.    
   
   
       10 . The spectroscopic polarimetry according to  claim 3 , wherein the polarizer and the second retarder are arranged such that an angle between the orientation of the transmission axis of the polarizer and the orientation of a fast axis of the second retarder is 45°.  
   
   
       11 . The spectroscopic polarimetry according to  claim 2 , further comprising a step of obtaining a spectral intensity for calibration by use of the polarimetric spectroscope in a state where an object to be measured having an unknown spectropolarization characteristic does not exist in a light path between the projection optical system and the analyzer, wherein 
 the step of obtaining at least one of spectropolarization parameters is a step of obtaining at least one of the spectropolarization parameters of the object to be measured by use of the spectral intensity regarding the object to be measured and the spectral intensity for calibration or data based upon the spectral intensity for calibration.    
   
   
       12 . The spectroscopic polarimetry according to  claim 11 , wherein 
 the step of obtaining the spectral intensity for calibration is a step of preparing an analyzer for calibration in a position in which light emitted from the projection optical system is received in a state where the object to be measured having an unknown spectropolarization characteristic does not exist in the light path between the projection optical system and the analyzer.    
   
   
       13 . The spectroscopic polarimetry according to  claim 11 , further comprising a step of obtaining the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder by use of the spectral intensity for calibration, wherein 
 the step of obtaining at least one of spectropolarization parameters is a step of obtaining at least one of the spectropolarization parameters of the object to be measured by use of the spectral intensity regarding the object to be measured, the retardation (φ 1 (σ)) of the first retarder, and the retardation (φ 2 (σ)) of the second retarder, which are obtained by use of the spectral intensity for calibration.    
   
   
       14 . The spectroscopic polarimetry according to  claim 8 , wherein 
 the step of acquiring data showing the relation between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder is a step which comprises:    obtaining the spectral intensity for calibration by use of the polarimetric spectroscope in a state where the object to be measured having an unknown spectropolarization characteristic does not exist in the light path between the projection optical system and the analyzer; and    obtaining the data showing the relation between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder by use of the obtained spectral intensity for calibration.    
   
   
       15 . The spectroscopic polarimetry according to  claim 9 , wherein 
 the step of acquiring data showing the relation between the retardation variation (Δφ 1 (σ)) of the first retarder and the retardation variation (Δφ 2 (σ)) of the second retarder is a step which comprises:    obtaining the spectral intensity for calibration by use of the polarimetric spectroscope in a state where the object to be measured having an unknown spectropolarization characteristic does not exist in the light path between the projection optical system and the analyzer; and    obtaining the data showing the relation between the retardation variation (Δφ 1 (σ)) of the first retarder and the retardation variation (Δφ 2 (σ)) of the second retarder by use of the obtained spectral intensity for calibration.    
   
   
       16 . The spectroscopic polarimetry according to  claim 1 , comprising a step of obtaining the spectroscopic quasi-tokes parameter of the object to be measured by use of the obtained spectral intensity.  
   
   
       17 . The spectroscopic polarimetry according to  claim 16 , wherein 
 the plurality of retarders that the projection optical system comprises are a first retarder and a second retarder,    the light source, the polarizer, the first retarder and the second retarder are arranged such that light emitted from the light source transmits through the polarizer, the second retarder and the first retarder in this order, the orientation of the transmission axis of the polarizer disagrees with the orientation of the principal axis of the second retarder, and the orientation of the principal axis of the second retarder disagrees with the orientation of the principal axis of the first retarder,    the spectroscopic polarimetry further comprises a step of acquiring data showing the relation between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder, and    the step of obtaining the spectroscopic quasi-tokes parameter comprises:    obtaining, from the obtained spectral intensity,    at least one of the spectral intensity component (first spectral intensity component) which nonperiodically vibrates with wavenumber and the spectral intensity component (third spectral intensity component) which vibrates at a frequency depending upon the retardation (φ 2 (σ)) of the second retarder and not depending upon the retardation (φ 1 (σ)) of the first retarder, with wavenumber, and    at least one of the spectral intensity component (second spectral intensity component) which vibrates at a frequency depending upon the difference between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder with wavenumber, the spectral intensity component (fourth spectral intensity component) which vibrates at a frequency depending upon the sum of the retardation (φ 1 (σ) of the first retarder and the retardation (φ 2 (σ)) of the second retarder with wavenumber, and the spectral intensity component (fifth spectral intensity component) which vibrates at a frequency depending upon the retardation (φ 1 (σ)) of the first retarder and not depending upon the retardation (φ 2 (σ)) of the second retarder, with wavenumber; and    obtaining the retardation (φ 1 (σ)) of the first retarder, the retardation (φ 2 (σ)) of the second retarder and the spectroscopic quasi-Stokes parameter by use of the data showing the relation between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder, and each of the obtained spectral intensity components.    
   
   
       18 . The spectroscopic polarimetry according to  claim 16 , wherein 
 the plurality of retarders that the projection optical system comprises are a first retarder and a second retarder,    the light source, the polarizer, the first retarder and the second retarder are arranged such that light emitted from the light source transmits through the polarizer, the second retarder and the first retarder in this order, the orientation of a transmission axis of the polarizer disagrees with the orientation of a principal axis of the second retarder, and the orientation of the principal axis of the second retarder disagrees with the orientation of a principal axis of the first retarder,    the spectroscopic polarimetry further comprises the steps of:    acquiring data showing the relation between the retardation variation (Δφ 1 (σ)) of the first retarder and the retardation variation (Δφ 2 (σ)) of the second retarder; and    acquiring a reference value (φ 1   (i) (σ)) for calibration of retardation of the first retarder and a reference value (φ 2   (i) (σ)) for calibration of retardation of the second retarder, and    the step of obtaining the spectroscopic quasi-Stokes parameter comprises:    obtaining, from the obtained spectral intensity,    at least one of the spectral intensity component (first spectral intensity component) which nonperiodically vibrates with wavenumber and the spectral intensity component (third spectral intensity component) which vibrates at a frequency depending upon the retardation (φ 2 (σ)) of the second retarder and not depending upon the retardation (φ 1 (σ)) of the first retarder, with wavenumber, and    at least one of the spectral intensity component (second spectral intensity component) which vibrates at a frequency depending upon the difference between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder with wavenumber, the spectral intensity component (fourth spectral intensity component) which vibrates at a frequency depending upon the sum of the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder with wavenumber, and the spectral intensity component (fifth spectral intensity component) which vibrates at a frequency depending upon the retardation (φ 1 (σ)) of the first retarder and not depending upon the retardation (φ 2 (σ)) of the second retarder, with wavenumber;    obtaining the retardation (φ 2 (σ)) of the second retarder and the retardation variation (Δφ 2 (σ)) of the second retarder from the reference value (φ 2   (i) (σ)) for calibration by use of the obtained spectral intensity;    obtaining the retardation variation (Δφ 1 (σ)) of the first retarder by use of the obtained retardation variation (Δφ 2 (σ)) of the second retarder and data showing the relation between the retardation variation (Δφ 1 (σ)) of the first retarder and the retardation variation (Δφ 2 (σ)) of the second retarder;    obtaining the retardation (φ 1 (σ)) of the first retarder from the reference value (φ 1   (i) (σ)) for calibration of retardation of the first retarder and the obtained retardation variation (Δφ1(σ)) of the first retarder; and    obtaining the spectroscopic quasi-Stokes parameter by use of each of the obtained spectral intensity components, the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder.    
   
   
       19 . A polarimetric spectroscope, comprising: 
 a projection optical system, comprising a light source, a polarizer and a plurality of retarders, where the light source, the polarizer and the plurality of retarders are arranged such that light emitted from the light source is irradiated on the object to be measured after passing through the polarizer and the plurality of retarders in this order;    an analyzer for allowing light to transmit therethrough, the light having been emitted from the projection optical system and reflected on or transmitted through the object to be measured; and    a device for obtaining the spectral intensity of the light having transmitted through the analyzer.    
   
   
       20 . The polarimetric spectroscope according to  claim 19 , wherein 
 the plurality of retarders that the projection optical system comprises are a first retarder and a second retarder, and    the light source, the polarizer, the first retarder and the second retarder are arranged such that light emitted from the light source transmits through the polarizer, the second retarder and the first retarder in this order, the orientation of a transmission axis of the polarizer disagrees with the orientation of a principal axis of the second retarder, and the orientation of the principal axis of the second retarder disagrees with the orientation of a principal axis of the first retarder.    
   
   
       21 . The polarimetric spectroscope according to  claim 20 , wherein the polarizer and the second retarder are arranged such that an angle between the orientation of the transmission axis of the polarizer and the orientation of a fast axis of the second retarder is 45°.  
   
   
       22 . The polarimetric spectroscope according to  claim 19 , further comprising: 
 an analyzer for calibration, detachably provided in a position in which light emitted from the projection optical system is received in a state where an object to be measured having an unknown spectropolarization characteristic does not exist in a light path between the projection optical system and the analyzer; and    a device for obtaining the spectral intensity of the light having transmitted through the analyzer for calibration.    
   
   
       23 . The polarimetric spectroscope according to  claim 19 , further comprising an optical fiber for projecting light which guides the light emitted from the light source to the polarizer.  
   
   
       24 . The polarimetric spectroscope according to  claim 23 , wherein the device for obtaining a spectral intensity comprises a light-reception element or a spectrometer, and further comprises an optical fiber for receiving light which guides the light having transmitted through the analyzer to the light-reception element or the spectrometer.  
   
   
       25 . A spectroscopic polarimeter, comprising: 
 a polarimetric spectroscope, which comprises    a projection optical system, comprising a light source, a polarizer and a plurality of retarders, where the light source, the polarizer and the plurality of retarders are arranged such that light emitted from the light source is irradiated on the object to be measured after passing through the polarizer and the plurality of retarders in this order,    an analyzer for allowing light to transmit therethrough, the light having been emitted from the projection optical system and reflected on or transmitted through the object to be measured, and    a device for obtaining the spectral intensity of the light having transmitted through the analyzer; and    an arithmetic unit for obtaining at least one of spectropolarization parameters of an object to be measured, by use of the spectral intensity.    
   
   
       26 . The spectroscopic polarimeter according to  claim 25 , wherein 
 the plurality of retarders that the projection optical system comprises are a first retarder and a second retarder,    the light source, the polarizer, the first retarder and the second retarder are arranged such that light emitted from the light source transmits through the polarizer, the second retarder and the first retarder in this order, the orientation of a transmission axis of the polarizer disagrees with the orientation of a principal axis of the second retarder, and the orientation of the principal axis of the second retarder disagrees with the orientation of a principal axis of the first retarder,    the arithmetic unit is made capable of using data showing the relation between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder,    the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder are obtained from the spectral intensity and the data showing the relation between the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder; and    at least one of the spectropolarization parameters of the object to be measured is obtained by use of the spectral intensity, the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder.    
   
   
       27 . The spectroscopic polarimeter according to  claim 25 , wherein 
 the plurality of retarders that the projection optical system comprises are a first retarder and a second retarder,    the light source, the polarizer, the first retarder and the second retarder are arranged such that light emitted from the light source transmits through the polarizer, the second retarder and the first retarder in this order, the orientation of the transmission axis of the polarizer disagrees with the orientation of the principal axis of the second retarder, and the orientation of the principal axis of the second retarder disagrees with the orientation of the principal axis of the first retarder,    the arithmetic unit is made capable of using data showing the relation between the retardation variation (Δφ 1 (σ)) of the first retarder and the retardation variation (Δφ 2 (σ)) of the second retarder, a reference value (φ 1   (i) (σ)) for calibration of retardation of the first retarder and a reference value (φ 2   (i) (σ)) for calibration of retardation of the second retarder,    the retardation (φ 2 (σ)) of the second retarder and the retardation variation (Δφ 2 (σ)) of the second retarder from the reference value (φ 2   (i) (σ)) for calibration are obtained from the spectral intensity,    the retardation variation (Δφ 1 (σ)) of the first retarder is obtained by use of the obtained retardation variation (Δφ 2 (σ)) of the second retarder and data showing the relation between the retardation variation (Δφ 1 (σ)) of the first retarder and the retardation variation (Δφ 2 (σ)) of the second retarder,    the retardation (φ 1 (σ)) of the first retarder is obtained from the reference value (φ 1   (i) (σ)) for calibration of retardation of the first retarder and the obtained retardation variation (Δφ 1 (σ)) of the first retarder, and    at least one of the spectropolarization parameters of the object to be measured is obtained by use of the spectral intensity, the retardation (φ 1 (σ)) of the first retarder and the retardation (φ 2 (σ)) of the second retarder.    
   
   
       28 . An optical device, comprising: 
 a projection optical system, comprising a polarizer and a plurality of retarders, where the polarizer and the plurality of retarders are arranged such that light incident on the polarizer is irradiated on the object to be measured after passing through the polarizer and the plurality of retarders in this order; and    an analyzer for allowing light to transmit therethrough, the light having been emitted from the projection optical system and reflected on or transmitted through the object to be measured.    
   
   
       29 . A light-projection device, comprising a polarizer and a plurality of retarders, wherein the polarizer and the plurality of retarders are arranged such that light incident on the polarizer is irradiated on the object to be measured after passing through the polarizer and the plurality of retarders in this order.  
   
   
       30 . The light-projection device according to  claim 29 , wherein 
 the plurality of retarders are a first retarder and a second retarder, and    the polarizer, the first retarder and the second retarder are arranged such that light incident on the polarizer transmits through the polarizer, the second retarder and the first retarder in this order, the orientation of a transmission axis of the polarizer disagrees with the orientation of a principal axis of the second retarder, and the orientation of the principal axis of the second retarder disagrees with the orientation of a principal axis of the first retarder.    
   
   
       31 . The spectroscopic polarimetry according to  claim 1 , wherein 
 the polarimetric spectroscope prepared in the step of preparing a polarimetric spectroscope further comprises a device for changing the azimuth angle of the analyzer,    the step of obtaining a spectral intensity is a step of obtaining a spectral intensity regarding the object to be measured in a plurality of states where azimuth angles of the analyzer are made different from one another, by use of the spectroscopic polarimetry, and    the spectroscopic polarimetry further comprises a step of obtaining at least one of the spectropolarization parameters of the object to be measured by use of the spectral intensity obtained in the plurality of states.    
   
   
       32 . The spectroscopic polarimetry according to  claim 1 , wherein 
 the step of preparing an object to be measured is a step of preparing an object to be measured which includes a sample and a polarization element on which light emitted from the sample is incident,    the polarimetric spectroscope to be prepared in the step of preparing a polarimetric spectroscope further comprises a device for changing the characteristic of the polarization element,    the step of obtaining a spectral intensity is a step of obtaining a spectral intensity regarding the object to be measured in a plurality of states where characteristics of the polarization element are made different from one another, by use of the spectroscopic polarimetry, and    the spectroscopic polarimetry further comprises a step of obtaining at least one of spectropolarization parameters of the sample by use of the spectral intensity obtained in the plurality of states.    
   
   
       33 . The spectroscopic polarimetry according to  claim 1 , wherein 
 the step of preparing an object to be measured is a step of preparing an object to be measured which includes a sample and a polarization element on which light emitted from the sample is incident,    the polarimetric spectroscope to be prepared in the step of preparing a spectroscopic polarimetry further comprises a device for changing the characteristic of the polarization element and a device for changing the azimuth angle of the analyzer,    the step of obtaining a spectral intensity is a step of obtaining a spectral intensity regarding the object to be measured in a plurality of states where characteristics of the polarization element, or azimuth angles of the analyzer, are made different from one another, by use of the spectroscopic polarimetry, and    the spectroscopic polarimetry further comprises a step of obtaining at least one of spectropolarization parameters of the sample by use of the spectral intensity obtained in the plurality of states.    
   
   
       34 . The polarimetric spectroscope according to  claim 19 , further comprising a device for changing the azimuth angle of the analyzer.  
   
   
       35 . The spectroscopic polarimetry according to  claim 19 , further comprising a device for changing the characteristic of the polarization element in a case where the object to be measured includes a sample and a polarization element on which light emitted from the sample is incident.  
   
   
       36 . The spectroscopic polarimetry according to  claim 19 , further comprising a device for changing the characteristic of the polarization element, and a device for changing the azimuth angle of the analyzer, in a case where the object to be measured includes a sample and a polarization element on which light emitted from the sample is incident.  
   
   
       37 . The optical device according to  claim 28 , further comprising a device for changing the azimuth angle of the analyzer.  
   
   
       38 . The optical device according to clam  28 , further comprising a device for changing the characteristic of the polarization element in a case where the object to be measured includes a sample and a polarization element on which light emitted from the sample is incident.  
   
   
       39 . The optical device according to  claim 28 , further comprising a device for changing the characteristic of the polarization element, and a device for changing the azimuth angle of the analyzer, in a case where the object to be measured includes a sample and a polarization element on which light emitted from the sample is incident.