http://experimentationlab.berkeley.edu/sites/default/files/AFMImages/butt_AFM.pdf

Force measurements with the atomic force microscope: Technique, interpretation and applications

With an optical interferometer, the free vibration spectra and the local vibration amplitude of four rectangular atomic force microscope cantilevers made of silicon have been examined experimentally in a spectral range of 100 kHz to 10 MHz. A good agreement with the flexural wave theory of elastic beams was found. Coupling to torsional vibrations was also observed. When the sensor tip of the cantilever is in contact with a sample surface the resonances are shifted in frequency and the vibration amplitudes along the cantilever change. A method is presented to calculate this frequency shift using a linear approximation for the tip–sample interaction forces, and the results are compared with the frequency shift calculated from the point‐mass model. The measured resonance frequencies of a surface‐coupled cantilever do not correspond as well to the theoretical ones as in the free case even if the elastic‐beam model is used. The reason for the disagreement is found to be the geometry of the commercial cantileve...

Vibrations of free and surface‐coupled atomic force microscope cantilevers: Theory and experiment

Measuring surface forces in aqueous electrolyte solution with the atomic force microscope

The present invention is directed to methods and apparatuses for performing temporal scanning using ultra-short pulsewidth lasers in which only minimal (micro-scale) mechanical movement is required. The invention also relates to methods for obtaining high-accuracy timing calibration, on the order of femtoseconds. A dual laser system is disclosed in which the cavity of one or more of the lasers is dithered, by using a piezoelectric element. A Fabry-Perot etalon is used to generate a sequence of timing pulses used in conjunction with a laser beam produced by the laser having the dithered laser cavity. A correlator correlates a laser pulse from one of the lasers with the sequence of timing pulses to produce a calibrated time scale. The methods and apparatuses of the present invention are applicable to many applications requiring rapid scanning and time calibration, including, but not limited to metrology, characterization of charge dynamics in semiconductors, electro-optic testing of ultrafast electronic and optoelectronic devices, optical time domain reflectometry, and electro-optic sampling oscilloscopes.

Scanning temporal ultrafast delay methods and apparatuses therefor

Thermomechanical noise of a free v-shaped cantilever for atomic-force microscopy.

An optical heterodyne measuring apparatus for effecting measurement of a subject, based on a phase difference and a frequency difference between a reference beat beam consisting of two laser beams having different frequencies, and a measuring beat beam which consists of the reference beat beam reflected by the subject. The apparatus includes a light source device for producing a first reference beat beam having a first beat frequency, and a second reference beat beam having a second beat frequence which is lower than the first beat frequency, a beat frequency detecting device, and a phase difference detecting device. The beat frequency detecting device detects a beat frequency between the first beat frequency of the first reference beat beam, and a beat frequency of a first measuring beat beam which consists of the first reference beat beam reflected by the subject. The phase difference detecting device detects a phase difference between the second reference beat beam, and a second measuring beat beam which consists of the second reference beat beam reflected by the subject.

Optical heterodyne measuring apparatus

An apparatus for optically measuring the roughness of a surface of a subject in a non-contacting manner, based on a heterodyne interference wherein a phase of a beat beam produced by a reference laser beam, and a measuring laser beam reflected by the surface of the subject and having a wavelength different from that of the reference laser beam is changed with a change in the length of an optical path of the measuring laser beam, which occurs due to a change in the surface roughness of the subject. The apparatus includes a laser source for producing the reference and measuring laser beams, a lens device having an object lens for converging the measuring laser beam on the subject surface, and a deflector for deflecting the measuring laser beam before the measuring laser beam is incident upon the subject surface, whereby the point of convergence of the measuring laser beam is moved on the subject surface in a direction parallel to the surface, while the subject is held stationary.

Surface roughness measuring apparatus utilizing deflectable laser beams

An optical waveguide element includes an optical waveguide formed on a light-transmissive dielectric substrate and having a higher refractive index than the refraction index of the substrate, the optical waveguide including a region having an effective refractive index which varies nonlinearly in a direction in which a light wave is propagated through the optical waveguide. The light wave guided through the optical waveguide enters the region, in which the angles of incidence and reflection of the guided wave at the boundary between the region and the substrate is gradually reduced due to the variation in the effective refractive index. When the angles of incidence and reflection of the guided wave becomes smaller than a critical angle, the guided wave is emitted out of the waveguide. Since the effective refractive index changes nonlinearly with respect to the distance the guided wave is propagated, the light emitted into the substrate tends to converge at a point, and the beam pattern of the emitted light is spread less.

Optical waveguide element, method of making the same and optical coupler employing optical waveguide element

A highly sensitive displacement sensor for atomic force microscopy is described which enables one to measure the relative displacement of the tip from a sample surface. The sensor is based on the differential heterodyne interferometer formed between the reflections from the microscope cantilever backside and the sample surface. As a result of using an optical common‐path construction, the sensor is essentially insensitive to the mechanical vibration, and achieves high stability at low frequencies, even though there are certain restrictions imposed by the reflection from the examined surface and the variable deflection mode. Images are presented demonstrating the atomic resolution of mica and graphite.

Improved differential heterodyne interferometer for atomic force microscopy

A programming device for an automatic sewing machine wherein a succession of stitches are formed along a desired stitching line registered via a stitch pattern record medium according to a batch of sewing instructions. The programming device comprises: stitch pitch setting means for setting a pitch of the stitches formed along the stitching line; means for sequentially reading coordinate positions spaced along the stitching line at an interval longer than the pitch set by the pitch setting means; first memory means for storing the coordinate position data read by the reading means; control means for sequentially reading out the stored coordinate position data such that the data of three consecutive coordinate positions are always available, and preparing a series of sewing instructions to form the stitches which are located on a circular arc passing the three consecutive positions defined by the read-out coordinate position data and which are equally spaced at the preset pitch; and second memory means for storing the prepared sewing instructions. The programming device preferably further comprises a spacing interval selector for setting an interval at which at least one additional succession of stitches are formed in parallel to the desired stitching line. In this specific form, the control means prepares at least one additional group of coordinate position data according to which are prepared sewing instructions for said additional succession of stitches.

Yoshinori Bessho

Papers

Optical heterodyne measuring apparatus

Surface roughness measuring apparatus utilizing deflectable laser beams

Optical waveguide element, method of making the same and optical coupler employing optical waveguide element

Improved differential heterodyne interferometer for atomic force microscopy

Programming device for an automatic sewing machine