Ultraviolet Measurement of Optical Memory Subsystems
Final rept. 11 Feb 1997-11 Feb 1998
AIR FORCE RESEARCH LAB ROME NY SENSORSDIRECTORATE
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This effort mapped out the wavelengths of the states within the bandgap which have enough absorption strength to be used to write the material. Since metal oxides are always highly defected materials, we predict that subbandgap light could also be used to drive other processes, such as catalysis, which were previously only thought to be possible with superbaridgap light. We found that using 385 am light lowered the threshold by a factor of about 1000 compared to blue-green wavelengths. We measured 100 ns write speed at 385 nm, which is close to the desired 50 ns write speed and measured 2.5 ns write from 400 to 700 mn. We showed that adding a layer of TiO2 lowered the threshold by a factor of 13. So doping and adding other materials should be investigated. We also showed that writing was possible by preheating the material with IR before applying light in the UV to blue-green range. So the two wavelength beams will not have to be strictly coaxial when writing the material, relaxing the requirements for a write head in a disk drive. We conclusively proved that the IR light acts only as heat.
- Electrooptical and Optoelectronic Devices