JPH04350524A - Polarization measuring device - Google Patents

Abstract

PURPOSE:To enable optical characteristics such as a dielectric thin film to be measured two-dimensionally by measuring a distribution of a polarization state within a flux of light for a polarization measuring device which measured polarization for measuring optical characteristics such as a dielectric thin film. CONSTITUTION:This device consists of a beam splitter 5 for separating a polarization which is in a specific polarization state into three fluxes of light, analyzers 6 with mutually different orientation angles, a dichroic mirror 8 for converting into each different color, a total reflection mirror 7 for changing them into a single flux of light, an image-forming lens 9, and a color CCD area sensor 10.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring the state of polarization.

0002

2. Description of the Related Art The state of polarization of a luminous flux is measured from the total amount of transmitted light by mechanically or electrically rotating the azimuth of an analyzer.

0003

[Problems to be Solved by the Invention] Conventional techniques have not been able to measure the distribution of polarization states within a light beam at high speed. When attempting to perform polarization measurements to measure the optical properties (film thickness, refractive index, etc.) of dielectric thin films, etc., conventional techniques have not been able to measure the two-dimensional properties of the thin film at high speed.

0004

[Means for Solving the Problems] The light beams that have passed through three polarizers having different azimuth angles are divided into R. G.
After passing through a color converter that corresponds to the B3 color, the image is formed on a color sensor.

[0005]

[Operation] The state of elliptically polarized light is expressed by three parameters. The state of elliptically polarized light (principal axis, ellipticity) can be completely defined by measuring the amount of transmitted light using three analyzers having different azimuth angles. By using a color converter to match the output of the three analyzers to the three primary colors, and measuring the output of the three colors individually using a color sensor, we can determine the amount of light that has passed through each analyzer, and thus measure the state of elliptically polarized light. can do. By focusing the light beam on a color area sensor, it is possible to measure the two-dimensional distribution of the polarization state within the light beam. By focusing the light beam on a color line sensor, it is possible to measure the one-dimensional distribution of the polarization state within the light beam. The optical constants of a thin film can be determined by irradiating a dielectric thin film with light of a certain polarization state at an appropriate angle of incidence and measuring the polarization state of the reflected light. A fixed amount of linearly polarized light is irradiated onto the sample surface at an appropriate angle of incidence, and the reflected light is transmitted through three analyzers with different azimuth angles, each of which is converted into three colors, and the amount of light is determined by a color sensor. By measuring each time, the polarization state of the reflected light can be determined, and the optical constants of the thin film can be determined. Polarized light beams of three colors with different principal axes and colors are irradiated onto the sample surface at an appropriate angle of incidence, and the reflected light is passed through an analyzer with a certain azimuth angle, and then the amount of transmitted light of the three colors is measured individually by a color sensor. If measured, the optical constants of the thin film can be similarly determined from the principle of symmetry of the optical system.

[0006]

[Examples] Examples of the present invention will be described below.

[Example 1] White light from light source (1) or R. G. B
The combined light of the three colors passes through a collimator lens (2) and is converted into linearly polarized light by a polarizer (3). The light is irradiated onto the sample (11) at an appropriate angle of incidence, and the reflected light passes through the condenser lens (4) and is separated into three beams by the beam splitter (5), each of which is directed in a different direction. It passes through a corner analyzer (6) and a dichroic mirror (8) with different color transmission characteristics. As a result, polarized light with different azimuthal angles will have different colors. These light beams pass through a total reflection mirror (7) and an imaging lens (9).
) is imaged onto the color CCD area sensor (10) as a single beam of light. Area sensor (10
) is the intensity of each color on the reflected elliptically polarized light.
) corresponds to the intensity corresponding to the azimuth angle.

[Embodiment 2] Ultraviolet light from an ultraviolet light source (1) is linearly polarized by a polarizer (3) via a collimator lens (2). The light is incident on the sample (11) at an appropriate angle of incidence, and the reflected light passes through the condenser lens (4) and is separated into different beams by the beam splitter (5), each of which is detected at a different azimuth angle. Let photons (6) pass. After each analyzer (6), each R. G.
A fluorescent screen (12) for wavelength conversion to B and R for sharpening the emission spectrum. G. B color filter (13
). The light that has passed through these is converted into a single beam by a total reflection mirror (7), a beam splitter (14), and an imaging lens (9) and sent to a CCD color area sensor (10).
image on top. The intensity of each color on the area sensor (10) corresponds to the intensity of the reflected elliptically polarized light corresponding to the azimuth angle of the analyzer (6). In this arrangement, unlike in Examples 1 and 3, there is no relation to the wavelength characteristics of the sample (11).

[Example 3] Totally reflecting mirror (7) for light from white light source (1)
The light is separated into three colors by a dichroic mirror (8) having different color transmission characteristics, and each color is passed through a polarizer (3) having a different azimuth angle. These polarizers are arranged so that their Jones matrices are linearly independent of each other (e.g. +4
5°, 0°, -45°) are selected. These light beams are passed through a beam splitter (5) and a collimator lens (2) to irradiate the sample (11) as parallel light beams at an appropriate angle of incidence, and the reflected light is converted into linearly polarized light through an analyzer (6).
Color C passes through the condensing lens (4) and the imaging lens (9).
An image is formed on the CD area sensor (10). Sample (1
1) and the characteristic matrix of the analyzer (6) are (M), (N), the incident light is (IRi), (IGi), (IBi), and the reflected light is (
IRo), (IGo), (IBo). (IRo) = (N) (M) (IRi) (IGo) = (N) (M) (IGi) (IBo) = (N) (M) (IBi) If the matrix is normalized by the loss coefficient, ( M) is a unimodular (2,2) matrix with two independent variables, and (N
) is known and the R. G. From the intensity of B (IRo
), (IGo), and (IBo) are obtained, so (M) can be calculated.

[Embodiment 4] White light from light source (1) or R. G. B
The combined light of the three colors passes through a collimator lens (2) and is converted into linearly polarized light by a polarizer (3). The sample (11) is irradiated with the light at an appropriate angle of incidence, and the reflected light is separated into three beams by a beam splitter (5) and a polarizing beam splitter (15) via a condenser lens (4). The analyzer (6) and the polarizing beam splitter (15) are set so that the three light beams become polarized lights having different azimuth angles. Imaging lens (9), R. G. The color CCD area sensor (
10) Image on. The intensity of each color on the area sensor (10) corresponds to the intensity of the reflected elliptically polarized light corresponding to different azimuthal angles. This color sensor (10
) can be displayed on a display to directly view the two-dimensional distribution of polarization states.

[0007]

[Effects of the Invention] The distribution of polarization states within a light beam can be measured at high speed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of an optical system in Example 1 of the present invention.

FIG. 2 is a schematic diagram showing the configuration of an optical system in Example 2 of the present invention.

FIG. 3 is a schematic diagram showing the configuration of an optical system in Example 3 of the present invention.

FIG. 4 is a schematic diagram showing the configuration of an optical system in Example 4 of the present invention.

[Explanation of sign]

1 Light source 2 Collimator lens 3 Polarizer 4 Condensing lens 5 Beam splitter 6 Analyzer 7 Total reflection mirror 8 Dichroic mirror 9 Imaging lens 10 Color CCD area sensor 11
Sample 12 Fluorescent screen 13 Color filter 14 Beam splitter

Claims (1)

[Claims] Claim 1: Each of the light beams passing through three polarizers having different azimuth angles is R. G. A polarization measuring device characterized by passing through a color converter corresponding to B3 colors and then forming an image on a color sensor.