Photothermal heterodyne imaging of individual nonfluorescent nanoclusters and nanocrystals.

Stéphane Berciaud (1) , Laurent Cognet (1) , Gerhard A Blab (1) , Brahim Lounis (1)

1 CPMOH - Centre de physique moléculaire optique et hertzienne

We introduce a new, highly sensitive, and simple heterodyne optical method for imaging individual nonfluorescent nanoclusters and nanocrystals. A 2 order of magnitude improvement of the signal is achieved compared to previous methods. This allows for the unprecedented detection of individual small absorptive objects such as metallic clusters (of 67 atoms) or nonluminescent semiconductor nanocrystals. The measured signals are in agreement with a calculation based on the scattering field theory from a photothermal-induced modulated index of refraction profile around the nanoparticle.

Mots clés: Single molecule detection; gold nanoparticles; semiconductor nanocristal; quantum dots; photothermal effect

Domaines: Optique [physics.optics]; Autre [cond-mat.other]

Stéphane Berciaud, Laurent Cognet, Gerhard A Blab, Brahim Lounis. Photothermal heterodyne imaging of individual nonfluorescent nanoclusters and nanocrystals.. Physical Review Letters, 2004, 93 (25), pp.257402. ⟨10.1103/PhysRevLett.93.257402⟩. ⟨hal-00002698v2⟩