High-contrast topography-free sample for near-field optical microscopy

Kalkbrenner, Thomas; Graf, M.; Durkan, Colm; Mlynek, J.; Sandoghdar, Vahid

doi:10.1063/1.125984

Cited by 17 publications

(11 citation statements)

References 17 publications

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“…After removing the polymer colloids, we anneal the sample at 1100 C for about 40 minutes to convert the triangular metallic islands to quasi-spherical features, whereby the diameter of the latter (110 nm) is controlled by the thickness of the initial gold deposition and annealing duration [19]. Next, we cover the gold nanoparticles with PMMA, float the resulting film in water, flip it and place it on a glass substrate [20]. This yields a very flat film, in which the embedded gold nanoparticles touch the upper surface.…”

mentioning

confidence: 99%

Spontaneous emission enhancement of a single molecule by a double-sphere nanoantenna across an interface

Lee¹,

Eghlidi²,

Chen³

et al. 2012

Opt. Express

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We report on two orders of magnitude reduction in the fluorescence lifetime when a single molecule placed in a thin film is surrounded by two gold nanospheres across the film interface. By attaching one of the gold particles to the end of a glass fiber tip, we could control the modification of the molecular fluorescence at will. We find a good agreement between our experimental data and the outcome of numerical calculations.

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mentioning

confidence: 99%

Spontaneous emission enhancement of a single molecule by a double-sphere nanoantenna across an interface

Lee¹,

Eghlidi²,

Chen³

et al. 2012

Opt. Express

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“…The transmission image shows clearly the absorption at the membrane, now appearing as four bright spots along the length instead of two bright spots as for one separated bacterium. This clearly indicates that the brighter spots toward the end in an individual bacterium are not topography artifacts due to the constant tip-surface feedback at the cell edge [16], and are indeed features related to internal structures of the bacteria.…”

Section: Methodsmentioning

confidence: 96%

Near-Field Scanning Optical Images of Bacteria

et al. 2001

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Near field scanning optical microscopy (NSOM) and spectroscopy techniques were used to study the shape and the cell membrane details in bacteria. We present transmission and topographic images for the bacteria Pseudomonas aeruginosa using the Aurora NSOM from ThermoMicroscopes. The P. aeruginosa has been widely studied due to its clinical importance in many infectious diseases. The samples were stained by the Gram method and we measured the absorption of laser light at 488 nm by the dye (Safranin) fixed at the bacteria membrane. To obtain good images we had to improve the sample preparation in order to obtain isolated bacteria at the microscope slab. This was achieved using individual colonies, from a dry growth procedure, diluted in physiologic solution. Comparison of the topographic and transmission images give information on the shape and details of the absorption of the laser light by the cell membrane. The results show patterns that depend on the thickness and shape of the membrane, thus revealing details of the cell membrane with nanometer resolution. These results could be an important tool for instance in studies of the effects of antibiotics on the cell membrane.

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“…The probe was scanned over a specimen in contact mode at constant force using an optical lever system well known from the AFM (Meyer & Amer, 1988). For the test sample, we used a slightly modified high‐contrast, topography‐free specimen adapted from Kalkbrenner et al . (2000), which avoids cross‐talk between topographical features and the near‐field optical signal.…”

Section: Snom Experimentsmentioning

confidence: 99%

Fabrication of near‐field optical apertures in aluminium by a highly selective corrosion process in the evanescent field

Haefliger

Stemmer

2003

Journal of Microscopy

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SummaryA simple, one-step process to fabricate high-quality apertures for scanning near-field optical microscope probes based on aluminium-coated silicon nitride cantilevers is presented. A thin evanescent optical field at a glass-water interface was used to heat the aluminium at the tip apex due to light absorption. The heat induced a breakdown of the passivating oxide layer and local corrosion of the metal, which selectively exposed the front-most part of the probe tip from the aluminium. Apertures with a protruding silicon nitride tip up to 72 nm in height were fabricated. The height of the protrusion was controlled by the extent of the evanescent field, whereas the diameter depended on the geometry of the probe substrate. The corrosion process proved to be self-terminating, yielding highly reproducible tip heights. Near-field optical resolution in a transmission mode of 85 nm was demonstrated.

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High-contrast topography-free sample for near-field optical microscopy

Cited by 17 publications

References 17 publications

Spontaneous emission enhancement of a single molecule by a double-sphere nanoantenna across an interface

Spontaneous emission enhancement of a single molecule by a double-sphere nanoantenna across an interface

Near-Field Scanning Optical Images of Bacteria

Fabrication of near‐field optical apertures in aluminium by a highly selective corrosion process in the evanescent field

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