Observation device and observation method
An observation apparatus includes a light source, a lens, a polarizer, a first prism, a condenser lens, an objective lens, a second prism, a ¼ wave plate, a lens, a polarization camera, and an analysis unit. Each of the first prism and the second prism is, for example, a Wollaston prism or a Nomarski prism. The ¼ wave plate inputs light output from the second prism, and outputs two circularly polarized light beams having different rotation directions. The polarization camera inputs two light beams being circularly polarized in different rotation directions by the ¼ wave plate, and acquires an interference image on an imaging plane for each of three or more polarization components.
1. An optical module being used with a differential interference contrast microscope including a first prism, and a second prism provided at a subsequent stage of the first prism, the optical module comprising:
a relay optical system constituting a part of an imaging optical system configured to form an image by inputting light generated in an observation object placed between the first prism and the second prism in the differential interference contrast microscope, and configured to input light output from the second prism of the differential interference contrast microscope;
a polarization conversion element provided on an optical path of the relay optical system, and configured to input the light and output two circularly polarized light beams having different rotation directions; and
a polarization camera having an imaging plane disposed at a position where the image is formed by the relay optical system, and configured to input the two circularly polarized light beams having different rotation directions output from the polarization conversion element and simultaneously acquire three or more interference images on the imaging plane for three or more polarized light components.
2. The optical module according to claim 1 , wherein the polarization conversion element is a ¼ wave plate.
3. The optical module according to claim 1 further comprising a polarization conversion compensation optical element provided separately from the polarization conversion element, and configured to reduce polarization conversion occurring in an optical element other than the second prism and the polarization conversion element in the imaging optical system.
4. The optical module according to claim 3 , wherein the polarization conversion compensation optical element is a mirror configured to compensate for a reflection property of a dielectric multilayer mirror provided in the imaging optical system, or a wave plate.
5. The optical module according to claim 1 , wherein the polarization camera has a configuration in which a plurality of pixels are arranged two-dimensionally in the imaging plane, and is configured to acquire a two-dimensional interference image.
6. The optical module according to claim 1 , wherein the polarization camera has a configuration in which a plurality of pixels are arranged one-dimensionally in the imaging plane, and is configured to acquire a one-dimensional interference image.