Abstract: An illumination system for a STED optical microscope includes an illumination light path consisting of an illumination light source and an optical elements. The illumination light path includes a first light filter, a second light filter, a polarizing light splitter, a first quarter wave plate, a first dichroic element, a light path delay unit, a phase plate, a second dichroic element, and a second quarter wave plate arranged in sequence along the transmission direction of the light path. The light beam emitted from the illumination light source is divided into two coaxial light beams after transmitted by the illumination light path. A first light beam is incident to a microscope objective to form a first light spot, a second light beam is incident to the microscope objective to form a second light spot, and the center of the first light spot coincides with that of the second light spot.

Abstract: An illumination system for a STED optical microscope includes an illumination light path consisting of an illumination light source and an optical element. The illumination light path includes a first light filter, a second light filter, a polarizing light splitter, a first quarter wave plate, a first dichroic element, a light path delay unit, a phase plate, a second dichroic element, and a second quarter wave plate arranged in sequence along the transmission direction of the light path. The light beam emitted from the illumination light source is divided into two coaxial light beams after transmitted by the illumination light path. A first light beam is incident to a microscope objective to form a first light spot, a second light beam 12 is incident to the microscope objective to form a second light spot, and the center of the first light spot coincides with that of the second light spot.