ISO 24013 pdf download – Optics and photonics -Lasers andlaser-related equipment- Measurementof phase retardation of optical components for polarized laser radiation.
6 Preparation of test sample and measuring arrangement
6.1 General
Storage, cleaning and the preparation of the test semples are carried out in accordance with the manufacturer’s instructions for normal use.
The environment of the testing place consists of dust-free filtered air with less than 60 % relative humidity. The residual dust is reduced in accordance with, for exanple, the clean-room ISO class 7 as defined In
ISO 14644-1:1999.
A linearly polarized laser shall be used as the radiation source. To keep errors as low as possible, the beam power stability should be as high as possible.
Wavelength, angle of incidence and state of polarization of the laser radiation used for the measurement shal correspond to the values specified by the manufacturer for the use of the test sample If ranges are accepted for these three quantities, any combinatun of wavelength, angle of incidence and state of polarization may be chosen from these ranges.
6.2 Laser beam preparation
The accuracy of the measurement Is strongly influenced by a clear definition of the slate of polarization of the laser beam. Therefore it is necessary to prepare the polarization state of the probe beam (linearly or circularly) caret uly,
If the expected phase retardation is near x/2. a linearly polarized beam shall be used. The quantity (1 – p). where p is the degree of linear polanzation. shaM be less than i03. This shall be verified by using the analyser without the sample in the beam path.
NOTE I Such a stale of polanzaon c be achieved by using a keaity polarized laser beam in conitiination with additional polarizing elements
If the expected phase retardation is near zero, a circularly polarized beam shall be used. The degree of linear polarization p shall be less than lOs. This shall be verified by using the analyser without the sample In the beam path
NOTE 2 Such a state of polanzaon cern be achieved by using a bnearty polarized laser beam in contaiabon with additional linearly polarizing elements and a phase retarding element.
All optical elements shall not increase the quantity m the case of a linearly polarized beam and p In the case of a circularly polarized beam, by more than to. For this reason the use of folding mirrors in the test setup is discouraged and all other optical elements shall be used under normal Incidence.
6.3 Sample adjustment and system calibration
6.3.1 ReflectIve samples
The sample shall be mounted very accurately at the angle of Incidence according to the manufacturer’s specification. The deviation from the intended angle of use shall be less than 2 mrad. For this purpose the component shall be mounted on a precision rotary stage. Back reflecting the laser beam into the laser cavity defines the normal incidence.
8.2.1 Evaluation for zero absorptance difference
The phase retda(ion caused by the test sample is given by the difference of the measured phase difference of the probe beam [without tesi sample, see 7.1.1. EquatIon (1)J and the measured phase difference after passing the test sample Isee 7.1.2, Equation (2)3.
8.2.2 Evaluation for non-zero absorptance difference
The phase retardation caused by the test sample is given by the difference of the measured phase difference of the probe beam [without test sample, see 7.1.1. Equation (1)1 and the measured phase difference after passing the test sample (see 7.1.3). AdditIonally, the relative absoiptance difference can be detem,ined according to Equation (3).
8.3 Evaluation for ir/2 phase retardation
8.3.1 Evaluation for zero absorptarlce difference
The phase retardation caused by the test sample is given by the difference of the measured phase difference of the probe beam Iwithout test sple, see 7.1.1, Equation (1)1 and the measured phase difference after passing across the lest sample (see 71,2, Equation (2)),
8.3.2 Evaluation for non-zero absorplanc. difference
The phase retardation caused by the test sample is given by the difference of the measured phase difference of the probe beam [without test sample, see 7.1.1, Equation (1)1 and the measured phase difference after passing the test sample (see 7.1.3). Additionally, the relative absorptance difference can be determined according to Equation (3),
9 Test report
The following information shall be included in the test repoit
a) General information
1) test has been performed in accordance with ISO 24013:2006;
2) date of test;
3) name and address of test organization.
ISO 24013 pdf download – Optics and photonics -Lasers andlaser-related equipment- Measurementof phase retardation of optical components for polarized laser radiation
