Air gap dependence of write and read characteristics in magneto-optical recording with solid immersion lens

A near-field MO recording was done at a wavelength of 680 nm using a super-hemispherical solid immersion lens (SIL) flying head. The SIL optical system has a designed NA of 1.46. The SIL can write and read marks to a minimum length of about 0.15 /spl mu/m. The optical readout characteristic with the SIL is not very sensitive to air gaps if the air gaps are kept below about 130 nm.