Confocal laser scanning microscope

1. A confocal laser scanning microscope comprising:

a laser beam source for outputting a laser beam;

a laser optical system which irradiates a sample with the laser beam output by the laser beam source and which detects a measurement beam coming from the sample so as to acquire a confocal image of the sample;

a light source which emits illumination light having an arbitrary wavelength;

an optical-microscope optical system which directs the illumination light emitted from the light source to the laser optical system to illuminate the sample and which measures illumination light coming from the sample, thereby obtaining a non-confocal image of the sample; and

a plurality of differential interference optical elements which are detachably insertable in optical axes of the laser optical system and the optical-microscope optical system, and which are used for detecting a measurement beam coming from the sample so as to acquire a differential interference image of the sample.

2. The confocal laser scanning microscope according to claim 1 , wherein the optical elements include a differential interference prism, an analyzer and a polarizer.

3. The confocal laser scanning microscope according to claim 1 , wherein the differential interference prism and the analyzer are detachably insertable in the laser optical system.

4. The confocal laser scanning microscope according to claim 3 , wherein, when the optical-microscope optical system is used for acquiring the differential interference image of the sample, the differential interference prism and the analyzer are arranged in the laser optical system, and the polarizer is detachably arranged at a position where the illumination light emitted from the light source is guided to the laser optical system.

5. The confocal laser scanning microscope according to claim 3 , wherein, when the optical-microscope optical system is used for acquiring a simplified polarization image of the sample, the differential interference prism is detached from the laser optical system, the analyzer is arranged in the laser optical system, and the polarizer is arranged at the position where the illumination light emitted from the light source is guided to the laser optical system.

6. The confocal laser scanning microscope according to claim 3 , wherein, when the laser optical system is used for acquiring at least one of a confocal differential interference image of the sample and a non-confocal differential interference image of the sample, the differential interference prism is arranged in the laser optical system, the analyzer is detached from the laser optical system, and the polarizer is retracted from the position where the illumination light emitted from the light source is guided to the laser optical system.

7. The confocal laser scanning microscope according to claim 1 , further comprising:

a beam splitter located at a branch point from which the laser optical system and the optical-microscope optical system branch, and dividing the laser optical system and the optical-microscope optical system from each other;

a polarizing beam splitter arranged on an optical axis of the laser beam emitted from the laser beam source; and

a quarter-wavelength retardation plate which shifts the wavelength of the laser beam from the laser beam source by one quarter-wavelength, and which shifts the wavelength of the measurement beam coming from the sample by one quarter-wavelength,

the quarter-wavelength retardation plate being arranged on an optical axis between the beam splitter and the polarizing beam splitter.

8. The confocal laser scanning microscope according to claim 7 , wherein the beam splitter does not have polarizing characteristics.