Light scanning apparatus and image forming apparatus

An apparatus comprising:

• a first element in which a first fine structure configured to change a polarization state of a first light flux from a first light source is formed on at least one of an incident surface or an exit surface thereof;
• a deflecting unit configured to deflect the first light flux that has passed through the first element to scan a first scanned surface in a main scanning direction;
• and
• a first optical system configured to guide the deflected first light flux to the first scanned surface,
• wherein the first fine structure on at least one of the incident surface or the exit surface of the first element includes a plurality of protruding portions each extending in a first direction, the plurality of protruding portions being arrayed in a second direction perpendicular to the first direction, and
• wherein the following condition is satisfied:
• 1
• /
• 20
• ≤
• Δ
• 1
• /
• λ
• 1
• ≤
• 1
• /
• 6
• ,
• where Δ1 represents a phase difference between the first direction and the second direction of birefringence caused by the first fine structure on at least one of the incident surface or the exit surface of the first element, and λ1 represents a wavelength of the first light flux.