Optical sensor

An optical sensor comprising:

• a support film having a first main surface and a second main surface located opposite to the first main surface in a thickness direction;
• a thermoelectric-conversion material section including a plurality of first material layers and a plurality of second material layers, each of the plurality of first material layers having a strip shape, being formed of SiGe having p-type conductivity, and being configured to convert thermal energy into electric energy, each of the plurality of second material layers having a strip shape, being formed of SiGe having n-type conductivity, and being configured to convert thermal energy into electric energy, the thermoelectric-conversion material section being disposed on the first main surface;
• a heat sink disposed on the second main surface;
• and
• a light absorbing film disposed so as to form a temperature difference in each first material layer of the plurality of first material layers in longitudinal directions and each second material layer of the plurality of second material layers in longitudinal directions as viewed in a direction perpendicular to the first main surface, and configured to convert received light into thermal energy,
• wherein the plurality of first material layers and the plurality of second material layers are formed of a first phononic structure having a large number of pores,
• wherein the support film includes a first portion formed of a second phononic structure having a large number of pores and a second portion without the second phononic structure, and
• wherein at least a part of the first portion is in contact with the plurality of first material layers and the plurality of second material layers.