Sandia Corporation

Hmt Technology Corporation

Marco A Krumbuegel

Rick P Trebino

Ming M Yang

Peter C Jann

Reginald Lee

David N Fittinghoff

John N Sweetser

Thomas Tsang

Practical third-order frequency-resolved optical grating (FROG) techniques for characterization of ultrashort optical pulses are disclosed. The techniques are particularly suited to the measurement of single and/or weak optical pulses having pulse durations in the picosecond and subpicosecond regime. The relative quantum inefficiency of third-order nonlinear optical effects is compensated for through i) use of phase-matched transient grating beam geometry to maximize interaction length, and ii) use of interface-enhanced third-harmonic generation.

Apparatus and method for optical pulse measurement

An apparatus for measuring the height and diameter of laser-zone texture bumps on a rigid magnetic disk substrate is disclosed. The apparatus has a disk holder for supporting and rotating the substrate, and an optical beam-source assembly for directing a focused laser beam on the substrate, and for shifting the position of the beam's illumination spot on the substrate in a tracking (radial) direction. An optical detection assembly in the apparatus measures the deflection of the laser beam due to specular reflection of the beam by laser-zone texture bumps, as a function of time, in both scanning (circumferential) and tracking directions. A computational device in the apparatus functions to (i) calculate scanning and tracking deflection values which characterize beam deflections in the scanning and tracking directions, respectively, for a texture bump passing through the illumination spot produced by the beam on the substrate, (ii) select for bump-height analysis, those texture bumps whose scanning deflection values are above a selected threshold value and whose tracking deflection values are below a selected threshold value, indicative of a condition in which the selected textured bumps are each in focus and centered within said illumination spot, and (iii) determine the texture bump heights and diameters of the selected bumps from the beam deflections in the scanning direction. Also disclosed is a method by which the apparatus measures the light power which is scattered by the of laser-zone texture bumps on a rigid magnetic disk substrate.

Laser-bump sensor method and apparatus

Growing community of inventors

Danville, CA, United States of America

Marco A Krumbuegel