Structured illumination microscope, observation method , and control program

An observation method, comprising:

• irradiating, using a first illumination optical system and from a first direction, a sample with activating light for activating a fluorescent substance included in the sample;
• irradiating, using a second illumination optical system having an objective lens, and from a second direction that is different from the first direction, the sample with interference fringes of exciting light for exciting the fluorescent substance;
• controlling a direction and a phase of the interference fringes;
• forming, using an imaging optical system having the objective lens, an image of the sample irradiated with the interference fringes;
• taking, using an imaging element, the image formed by the imaging optical system;
• generating an image by using a plurality of the images taken by the imaging element, and;
• branching the exciting light into a plurality of diffracted light beams by diffraction, the plurality of diffracted light beams including at least one pair of +−1st order diffracted light beam;
• and
• blocking either the +1st order diffracted light beam or the −1st order diffracted light beam in the at least one pair while transmitting the other of the +1st order diffracted light beam or the −1st order diffracted light beam in the at least one pair.

A non-transitory tangible media storing therein a control program for causing a computer to implement:

• irradiating, using a first illumination optical system and from a first direction, a sample with activating light for activating a fluorescent substance included in the sample;
• irradiating, using a second illumination optical system having an objective lens, and from a second direction that is different from the first direction, the sample with interference fringes of exciting light for exciting the fluorescent substance;
• controlling a direction and a phase of the interference fringes;
• forming, using an imaging optical system having the objective lens, an image of the sample irradiated with the interference fringes;
• taking, using an imaging element, the image formed by the imaging optical system;
• generating an image by using a plurality of the images taken by the imaging element, and;
• branching the exciting light into a plurality of diffracted light beams by diffraction, the plurality of diffracted light beams including at least one pair of +−1st order diffracted light beam;
• and
• blocking either the +1st order diffracted light beam or the −1st order diffracted light beam in the at least one pair while transmitting the other of the +1st order diffracted light beam or the −1st order diffracted light beam in the at least one pair.