Richard Orr Maschmeyer

Precision molded-glass optics

Results achieved in high-precision molding of glass lenses are reported. The work concentrated on a 0.4- N.A. 8-mm diam lens with spherical surfaces. The glass is a specialty glass composition of index (d-line) 1.604 and Abbe number 50. Typical design tolerances which have been achieved in the molded glass lenses include relative surface figure replication of 0.06 Aim, thickness and diameter tolerances of A+/-10 Am, wedge of <10-3 rad, birefringence of less than one one-hundredth wave, and index homogeneity in the sixth decimal place. These results are directly applicable to molding precision glass aspheric lenses of similar tolerances.

Optical performance of a diffraction-limited molded-glass biaspheric lens

Optical performance results are reported for a molded-glass biaspheric lens. The 6-mm optical diam lens is intended for use in a laser-based optical disk application. The design with fabrication tolerances has an expected on-axis transmitted wave-front performance of 0.06-wave rms optical path difference (OPD) when tested at 0.6328 ,4m and a numerical aperture of 0.45. Transmitted wave-front aberrations were measured on actual molded lenses using a heterodyne interferometer. Typical performance was 0.05-0.08-wave rms- OPD. Experimental results involving mold rotation indicate that lens performance is primarily limited by a surface figure accuracy of one of the molds.

Hydrosilicates: hydration thermodynamics

Abstract Hydrosilicates are silicate glasses containing appreciable amounts of water-typically up to 20 w/o or more. The vapor pressure of steam in equilibrium with the hydrosilicate at various temperatures is a material characteristic which fully determines thermodynamic properties. Vapor pressure data were measured for one glass composition over a range of temperature, pressure, and water contents. The data fit the remarkably simple equation PEVP(T,W) = C(W) PH2O(T) where PH2O is the pressure saturated steam at temperature, T, and the factor C depends only on water content, W. Various thermodynamic properties were calculated from this equation. A theoretical understanding of the equation is presented which allows reliable extrapolation to other temperatures and suggests an easy way to characterize other glasses.

Optical Performance Of Molded-Glass Lenses For Optical Memory Applications

Optical performance results are reported for four different molded-glass lenses. All four lenses are intended for use as focus objectives in optical memory applications, including Compact Disc, Laser Disc, and optical storage pickups. All lenses have measured performance below 0.04 waves RMS on-axis at 0.780 micron. The lenses differ in the different performance features they emphasize. These features include excellent off-axis performance, longer working distance, a finite conjugate, and a higher numerical aperture.

Integration of optical devices on planar substrates

Thirty years after first envisioned, integrated planar optical devices are being commercialized. The markets driving commercialization are discussed. The types of planar devices and fabrication techniques are described. The technologies required for planar integration are then reviewed. Finally, some challenges facing commercialization are explored.