We developed magneto-optical head for high density and high information bit rate of 80Mbps (1,7 code) at outer diameter of 300mm disk(v=27.3m/s).To attain high bit rate, we developed the lens actuator of thin type(9mm in height) by mounting asherical plastic lens becase of requirement of driving sensitivity. Another approach was focused on the rigidity of lens holder for the improvement of transfer function. Furthermore ,we realized high density of 0.34/μm/bit recording by improvement of optical modulation by laser(λ=680nm) and lens(N.A.=0.55) and sensitivity of optical sensors,and noise reduction of head amplifier.
We study the practicality of the CWL-CAV(Constant minimum Wave Length - Constant Angular Velocity) method for high-density recording of a MO(Magneto-Optical) disk. To this system, the variable-trequency clock generating system for recording and the clock extracting system from reproduced signal which has wide capture-range are indispensable requisite. Therefore, we discussed them and reported the result of their experiment. As the result of them, the feasibility of the CWL-CAV method which make the deviation of the unit recording wave length less than ±0.5% was confirmed.
We have proposed a new correction method of the tracking deviation between two spots for 2-beam separated magneto-optical disk system. In this correction method, a wedge prism is utilized. Because of the prism refraction, the optical axis tilts a certain angle and simultaneously shifts to the opposite direction. Therefore, we can sufficiently reduce the offset component of the tracking error signal caused by the optical axis displacement, and get precise arrangement of the two spots.
Signal processing method in mark length recording on magneto-optical (MO) disk is discussed. We analize the frequency characteristics of the readout signal to find the linearity of the reading-writing characteristics using The detection methods are studied at the view multiple recording method. As the result, it is clarified that the direct point of the noise jitter. detection method has advantage compared to the 2nd differential detection method by 4.5〜6dB of SNR.
Principle, fabrication technique of fiber-probes, and system performance of a photon scanning tunneling microscope are reviewed. Possibility of applying this microscope to nano-fabrication is discussed. Experiments on ultrahigh density optical storage and single atom trapping for crystal growth are presented.