Development of Molecular Glasses for Use as Media for High-Density Optical Memory Based on Multi-Photon Absorption
Abstract
Objective: The objective of this project was the development of a class of organic materials that we have discovered into practical media for high-density optical data storage based upon multiphoton absorption (MPA). Background: The materials we investigated for data storage include molecular glasses and epoxy resins, and have the benefits of being inexpensive and readily available. It is also simple to modify the materials chemically to alter their physical and chemical properties. MPA involves the simultaneous absorption of two or more photons, none of which individually has sufficient energy to cause an electronic transition in a molecule. However, through collective interaction of n photons, such an event can occur. Because the absorption is non-resonant until the final step, the absorption probability is proportional to the laser intensity to the power of the number of photons involved in the process. As a result, MPA can be localized within the focal volume of a laser beam that has been focused through a microscope objective. By controlling the position of the focal volume in three dimensions, different regions of the sample can be addressed. The materials that we have developed do not fluoresce initially. However, 3- photon absorption of near-infrared radiation leads to a localized photochemical event that renders the materials fluorescent. The fluorescence of the photochemical product can then be read out by 2-photon absorption of near infrared radiation. Because writing of data is a 3-photon process and readout a 2-photon process, readout can be accomplished at considerably lower laser intensities.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 14, 2005
- Accession Number
- ADA444742
Entities
People
- John T. Fourkas
Organizations
- Boston College