Methods of manipulating particles on solid substrates via optothermally-gated photon nudging

A method comprising:

• illuminating a first location of an optothermal system with electromagnetic radiation, wherein the optothermal system comprises:
• a substrate having a first surface;
• a surfactant layer disposed on the first surface of the substrate, wherein the surfactant layer is a solid thin film;
• and
• a first particle disposed on the surfactant layer, such that the surfactant layer is between the first particle and the first surface of the substrate;
• wherein the first particle is a first optothermal particle, the substrate is an optothermal substrate, or a combination thereof;
• wherein:
• when the first particle is the first optothermal particle, then the first optothermal particle is in thermal contact with the surfactant layer;
• and
• when the substrate is the optothermal substrate, then the optothermal substrate is in thermal contact with the surfactant layer;
• wherein the first location of the optothermal system includes at least a portion of the first particle such that:
• the first particle scatters at least a portion of the electromagnetic radiation, thereby producing a first radiation-pressure force on the first particle;
• and
• when the first particle is the first optothermal particle, the first optothermal particle converts at least a portion of the electromagnetic radiation into thermal energy;
• wherein, when the substrate is the optothermal substrate, the optothermal substrate converts at least a portion of the electromagnetic radiation into thermal energy;
• and
• wherein the thermal energy converted by the first optothermal particle, the optothermal substrate, or a combination thereof is sufficient to generate a manipulation region at a location of the surfactant layer proximate to the first location of the optothermal system;
• thereby:
• generating the manipulation region at the location of the surfactant layer proximate to the first location of the optothermal system, wherein the manipulation region has a temperature sufficient to induce a first-order phase transition from a solid phase to a liquid or quasi-liquid phase in the portion of the surfactant layer within the manipulation region;
• inducing the first-order phase transition in the portion of the surfactant layer within the manipulation region;
• producing the first radiation-pressure force on the first particle, wherein the first radiation-pressure force is sufficient to translate the first particle from a first location within the manipulation region to a second location within the manipulation region;
• and
• translating the first particle from the first location within the manipulation region to the second location within the manipulation region.