Spectral profiles of the Hα line emitted from the large helical device plasma [O. Motojima et al., Phys. Plasmas 6, 1843 (1999)] have been measured with polarization-separation optics and a high-resolution spectrometer. Besides the underlying high-temperature component, which probably arises from charge-exchange recombination, the profiles are interpreted as superpositions of Zeeman profiles for two different magnetic field strengths. The emission locations are thus identified on the magnetic field map; the emissions are localized in the inner and outer regions just outside the ergodic layer, and each field-strength contribution to the overall Zeeman profile represents two radiator temperatures, and inward atom flow velocities in the range of (1–7)×103m∕s.

A novel method to stabilize the channeled spectropolarimeter is de- 40• C.

A novel method for the spectropolarimetric measurement of materials using the channeled spectrum is described. A pair of high order retarders are incorporated into the illuminating optics of a broadband spectropolarimeter, so that the sample under measurement is illuminated with the light that is modulated in the spectral-dependence of its polarization. The Fourier analysis of the channeled spectrum obtained from the spectropolarimeter allows determining the four spectrally-resolved polarimetric parameters of the sample simultaneously. This approach has a feature that it requires neither mechanically- nor electrically-controllable components for polarization modulation, similar to the previous method for the channeled spectropolarimetry in which the high-order retarders are placed in the receiving optics. The new method can offer the same information about the sample as has been obtained by the previous method, provided that all the optical components satisfy the principle of reciprocity. Furthermore, the new method has an additional advantage over the previous method that it is less susceptible to the sample-induced fluctuations of the wavefront or ray-direction. The effectiveness of this method is experimentally demonstrated with the measurement of a birefringent sample.

This paper describes a newly developed prototype system of the channeled spectroscopic ellipsometer ͑CSE͒. The new system has a feature that the major systematic and random error sources of the previous CSEs are effectively reduced or compensated for. In addition, the prototype preserves the advantageous features of the CSE in that it has a palm-size sensing head and that its acquisition time is as fast as 20 ms. Its performance is experimentally examined by use of 12 films whose thicknesses are ranging approximately from 3 to 4000 nm. The film thicknesses measured by the new CSE show good agreements with the ones by the rotating-compensator spectroscopic ellipsometer. The stability of the film-thickness measurement of the new CSE against the temperature change from 5 to 45°C is less than 0.11 nm. The CSE can open up new applications of the spectroscopic ellipsometers in which the compactness, the simplicity, and the rapid response are important.

A novel configuration for the channeled spectroscopic ellipsometer (CSE) is presented. The channeled spectroscopic ellipsometry is a snapshot method for the spectrally-resolved polarization analysis. In this method, multiple-order retarders are utilized to generate a channeled spectrum carrying information about the wavelength-dependent multiple parameters of polarization of light. This method has a feature that it requires no mechanical or active components for polarization-control, such as a rotating compensator and an electro-optic modulator. In spite of these advantages, however, the previouslyproposed configuration of the CSE has a drawback that it is susceptible to the ray-direction variation introduced by the angular fluctuation of the ellipsometric sample. To overcome this drawback, an alternative configuration for the CSE has been developed. In this configuration, the multiple-order retarders are inserted between a light source and a sample, so that the measured results are not affected by the fluctuations due to the reflection from the sample. A compact sensing head whose size is 160 mm (W) × 53 mm (H) × 30 mm (D) was realized using the new configuration, and applied for the snapshot measurement of the SiO 2 films deposited on a Si substrate, with the acquisition time of 20 ms. The measured thicknesses of the SiO 2 films are almost agree with the results from the rotating-compensator ellipsometer. The configuration that has the multiple-order retarders in the polarization-generating section can apply to other spectroscopic polarimeters to remove the influence of the ray-direction fluctuations due to the reflection or transmission from the sample.