Measurements of the contact potential difference between different materials have been performed for the first time using scanning force microscopy. The instrument has a high resolution for both the contact potential difference (better than 0.1 mV) and the lateral dimension (<50 nm) and allows the simultaneous imaging of topography and contact potential difference. Images of gold, platinum, and palladium surfaces, taken in air, show a large contrast in the contact potential difference and demonstrate the basic concept.

A modified version of the atomic force microscope is introduced that enables a precise measurement of the force between a tip and a sample over a tip-sample distance range of 30–150 Å. As an application, the force signal is used to maintain the tip-sample spacing constant, so that profiling can be achieved with a spatial resolution of 50 Å. A second scheme allows the simultaneous measurement of force and surface profile; this scheme has been used to obtain material-dependent information from surfaces of electronic materials.

We describe a new method for imaging magnetic fields with 1000 Å resolution. The technique is based on using a force microscope to measure the magnetic force between a magnetized tip and the scanned surface. The method shows promise for the high-resolution mapping of both static and dynamic magnetic fields.

We demonstrate the usefulness and high sensitivity of the atomic force microscope (AFM) for imaging surface dielectric properties and for potentiometry through the detection of electrostatic forces. Electric forces as small as 10−10 N have been measured, corresponding to a capacitance of 10−19 farad. The sensitivity of our AFM should ultimately allow us to detect capacitances as low as 8×10−22 F. The method enables us to detect the presence of dielectric material over Si, and to measure the voltage in a p-n junction with submicron spatial resolution.

Interferometric near-field optical microscopy achieving a resolution of 10 angstroms is demonstrated. The scattered electric field variation caused by a vibrating probe tip in close proximity to a sample surface is measured by encoding it as a modulation in the optical phase of one arm of an interferometer. Unlike in regular near-field optical microscopes, where the contrast results from a weak source (or aperture) dipole interacting with the polarizability of the sample, the present form of imaging relies on a fundamentally different contrast mechanism: sensing the dipole-dipole coupling of two externally driven dipoles (the tip and sample dipoles) as their spacing is modulated.

Photoinduced force microscopy resolves nanometer-scale topology with chemical recognition based on material absorption.

We demonstrate a new method whereby near-field optical microscope resolution can be extended to the nanometer regime. The technique is based on measuring the modulation of the scattered electric field from the end of a sharp silicon tip as it is stabilized and scanned in close proximity to a sample surface. Our initial results demonstrate resolution in the 3 nm range--comparable to what can be achieved with typical attractive mode atomic force microscopes. Theoretical considerations predict that the ultimate resolution achievable with this approach could be close to the atomic level.Following the demonstration of super-resolution by nearfield scarming microscopy at microwave frequencies' and its subsequent extension to the visible regionz9 the field of near-field scanning microscopy (NSOM) has attracted much attention. Particularly over the past few years, NSOM has enjoyed a rapid growth."15 This growth has been assisted by several important contributions to the technology such as the use of tapered single mode optical fibers," independently stabilizing the tip-sample spacing by shear-force contro17'8 and methods for measuring the polarization9 and fluorescence" of samples on the sub-50 nm scale. In this letter, we introduce a technique whereby the resolution of near-field optical microscopes can be extended below 1 nm, i.e., over an order of magnitude better than what has been achieved so far.The majority of near-field optical microscopes employ tapered single mode optical fibers coated on the sides with aluminum in order to form a subwavelength aperture at their ends. The aluminum (skin depth 12 nm at 633 nm wavelength) which is essential for the operation of most NSOMs serves to confine the light within the optical fiber as it enters the tip end thereby defining either a tiny light source (for illumination mode NSOM) or a tiny light collector (for collection mode NSOM). The smallest aperture that can be made in this way cannot be much smaller than twice the optical skin depth in aluminum, since the light has to be significantly attenuated as it leaks out of the fiber sides into the aluminum in order to define an aperture. Thus, spatial resolutions achieved in the NSOM are in the 30-50 nm range. This resolution although superior to the early images taken with NSOM are still an order of magnitude away from what can be achieved with typical attractive mode atomic force microscopes (AFMs>.~~ The concept we have explored is based on an idea that occurred to one of us several years ag0.t' Rather than transmitting light through a fine aperture, we use the spherical light scattering from a tip end of a standard Al?M or scanning tunnel microscopy @TM) to define the light source. Although in principle this concept allows one tomake scattering sources down to atomic dimensions (as in STM and AFM tips), it provides significant challenges for detecting the minute quantity of scattered light from the tip end in the presence of a large background. We have been able to overcome these difficulties. Here we present initial resu...

Phase-change storage is widely used in optical information technologies (DVD, CD-ROM and so on), and recently it has also been considered for non-volatile memory applications. This work reports advances in thermal data recording of phase-change materials. Specifically, we show erasable thermal phase-change recording at a storage density of 3.3 Tb inch(-2), which is three orders of magnitude denser than that currently achievable with commercial optical storage technologies. We demonstrate the concept of a thin-film nanoheater to realize ultra-small heat spots with dimensions of less than 50 nm. Finally, we show in a proof-of-concept demonstration that an individual thin-film heater can write, erase and read the phase of these storage materials at competitive speeds. This work provides important stepping stones for a very-high-density storage or memory technology based on phase-change materials.