Nanoparticle production in liquid with multiple-pulse ultrafast laser ablation
AssigneeImra America, Inc.
InventorsBing Liu, Zhendong Hu, Yong Che, Makoto Murakami
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Abstract
A method for generating nanoparticles in a liquid comprises generating groups of ultrafast laser pulses, each pulse in a group having a pulse duration of from 10 femtoseconds to 200 picoseconds, and each group containing a plurality of pulses with a pulse separation of 1 to 100 nanoseconds and directing the groups of pulses at a target material in a liquid to ablate it. The multiple pulse group ablation produces nanoparticles with a reduced average size, a narrow size distribution, and improved production efficiency compared to prior pulsed ablation systems.
Claims14
A method of producing nanoparticle solutions by laser ablation, comprising:
- generating a plurality of groups of laser pulses, each of said groups containing 2 to 50 laser pulses and having a group repetition rate comprising from 100 to 500 kHz, wherein a time separation between consecutive pulses within each of said groups is from 1 to 30 nanoseconds, said time separation being less than a relaxation time of a lattice heat of a target material;
- guiding said pulses toward said target material by use of a vibration mirror, said vibration minor guiding movement of said pulses on said target material such that a focal spot of said pulses moves at a speed of greater than 0.1 meters per second across said target material;
- and
- irradiating said target material with said pulses, said target material being disposed in a liquid and said irradiation producing nanoparticles from fragmentation of said target material in said liquid, said nanoparticles having an average particle size of less than 100 nanometers.
Dependencies are inferred from the claim text.