Author:

Keywords:

Science & Technology, Physical Sciences, Technology, Chemistry, Multidisciplinary, Chemistry, Physical, Nanoscience & Nanotechnology, Materials Science, Multidisciplinary, Chemistry, Science & Technology - Other Topics, Materials Science, photothermal microscopy, single-molecule imaging, single particle absorption spectroscopy, nanoparticles, label-free imaging, thermoplasmonics, nonlinear spectroscopy, nano-optics, live-cell imaging, thermal lens microscopy, THERMAL-LENS MICROSCOPE, FLUORESCENCE CORRELATION SPECTROSCOPY, CIRCULAR-DICHROISM, GOLD NANOPARTICLES, NONFLUORESCENT MOLECULES, SUPERRESOLUTION MICROSCOPY, METAL NANOPARTICLES, PROTEIN-DETECTION, CHIRAL MOLECULES, BACILLUS-CEREUS, single-particle absorption spectroscopy

Abstract:

The photothermal (PT) signal arises from slight changes of the index of refraction in a sample due to absorption of a heating light beam. Refractive index changes are measured with a second probing beam, usually of a different color. In the past two decades, this all-optical detection method has reached the sensitivity of single particles and single molecules, which gave birth to original applications in material science and biology. PT microscopy enables shot-noise-limited detection of individual nanoabsorbers among strong scatterers and circumvents many of the limitations of fluorescence-based detection. This review describes the theoretical basis of PT microscopy, the methodological developments that improved its sensitivity toward single-nanoparticle and single-molecule imaging, and a vast number of applications to single-nanoparticle imaging and tracking in material science and in cellular biology.