26 April 1982 Recording And Readout Testing Of Optical Recording Materials
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Abstract
In order to achieve high capacity archival optical storage, one of the key criteria is selecting a recording media which provides good writing and reading characteristics, good archival qualities and low cost. In this paper I shall describe a computer-controlled static material testing system (MTS) and samples of the test results as applied to Te-monolayer, Te-trilayer, Drexler, Thomson-CSF and the iron dispersion materials. For the recording and reading light source, an argon laser is operated at fundamental mode at X = 515 nm and is externally modulated with an acousto-optic modulator. For reading and focus-tracking, the modulator is operated at a low (-50 μW) level CW mode to provide illumination light. The modulator can also he pulsed at high power (up to 32 mW at the sample surface) with 0.8 p.m spot size at short intervals (>50 nsec) on command for recording laser pulses in coincidence with the read spot position, The focusing, readout, sample movement, laser power control. data acquisition and data analysis are all performed under mini-computer control with human intervention. Manual control mode is also provided and is very desirable for exploring new and unfamiliar materials. A video camera system provides direct viewing of the recording process. Reflectivity of the sample before (R0) and after (R1) the recording laser pulse is measured and read by the computer; from this data a modulation parameter (or contrast), (R0-Ri)/(R0 + R1), is calculated. This measurement is repeated many times to accumulate a statistically significant distribution which aives recording and material noise characteristics important for optical recording. The entire process is repeated at different recording powers to obtain recording power characteristics and sensitivity as well as different pulse widths to obtain reciprocity characteristics. Recording speed (hole opening time) can also be measured with the system. The results of these measurements will be presented for Te-monolayer, Te-trilayer, iron dispersion, Drexler, and Thomson-CSF materials.
© (1982) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David Cheng, "Recording And Readout Testing Of Optical Recording Materials", Proc. SPIE 0299, Advances in Laser Scanning Technology, (26 April 1982); doi: 10.1117/12.932552; https://doi.org/10.1117/12.932552
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