Illuminator and projector

An illuminator comprising:

• a light source apparatus that outputs first light containing a first polarized light component;
• an afocal system that includes a first lens and a second lens so arranged that optical axis directions thereof coincide with each other and reduces a light flux diameter of the first light;
• a polarization adjusting element that converts the first light, while transmitting the first light, into second light containing the first polarized light component and a second polarized light component a polarization direction of which is perpendicular to a polarization direction of the first polarized light component;
• a polarization separation element that separates the second light into light formed of the first polarized light component and light formed of the second polarized light component;
• a diffuser element on which one of the light beams separated by the polarization separation element is incident;
• a fluorescence emitting element on which the other one of the light beams separated by the polarization separation element is incident,
• wherein the polarization adjusting element is located between the first lens and the second lens;
• and
• a polarization adjusting mechanism that adjusts proportions of the first and second polarized light components in the second light by rotating the polarization adjusting element in a plane that intersects a center axis of the first light.