Light detector, light detection system, lidar device, and moving body

A light detector comprising:

• a junction region including a first semiconductor region of a first conductivity type and a second semiconductor region of a second conductivity type, the second semiconductor region being provided on the first semiconductor region;
• a first insulating portion having an inclined surface inclined with respect to a first direction from the first semiconductor region toward the second semiconductor region, a refractive index of the first insulating portion being larger than 1.5 and smaller than 2.0, an angle of the inclined surface with respect to the first direction being larger than 45 degrees and smaller than 74 degrees, the inclined surface being provided at a same height as at least a portion of the junction region and crossing the second direction from the junction region toward the first insulating portion;
• and
• a quenching part electrically connected to the second semiconductor region.