Method for accumulating microscopic objects, and method for detecting microscopic objects using same

A method for accumulating a plurality of microscopic objects dispersed in a liquid sample, the method comprising:

• preparing the liquid sample in contact with a photothermal conversion region;
• and irradiating the photothermal conversion region with light having a wavelength within an absorption wavelength range of the photothermal conversion region to generate a bubble in an irradiation region of the light and accumulate the plurality of microscopic objects around the bubble, wherein the photothermal conversion region includes:
• a first thin film having a first material configured to convert the light into heat;
• a structure in which a plurality of non-penetrating pores are periodically arranged on the first thin film;
• and a second thin film having a second material configured to convert the light into heat, the second thin film being disposed on at least a part of the structure, and wherein sizes of the plurality of non-penetrating pores and the irradiation region are determined such that at least two of the plurality of non-penetrating pores are entirely included in the irradiation region in a top view of the photothermal conversion region.