脈衝雷射讀取中央孔徑熱磁超解析磁光碟片

Abstract

熱磁超解析法(MSR)可用來讀取記錄於磁光碟片上小於光學繞射極限的記錄點。在MSR碟片中讀出信號的特性深受溫度分佈的影響，所以為了準確的控制溫度分佈，我們利用脈衝雷射來讀取信號。利用channel clock來觸發nsec級的脈衝雷射，皆碟片高速旋轉時可在磁光碟片上形成近似圓形的溫度分佈。利用讀出層和記錄層的磁交互摺合作用，可產生近似圓形的次微米孔徑以讀取次微米信號。在本誌文中，我們發現MSR-CAD碟片非常適合利用脈衝雷射來讀取資料，所測得CNR的值約較直流雷射讀取法高1.9dB，使檢出信號品質獲得明顯的改善。

Magnetically induced super resolution (MSR) is used to read below-diffraction-limited marks recorded on magneto-optical (MO) disks. In an MSR disk, readout signal characteristies is mainly determined by its temperature profile. So, in order to accurately control the temperature profile, a readout by pulsed irradiation is applied. Nanosecond pulse driven by channel clock is irradiated onto MO media to create a quasi-circular temperature profile on an optical disk spinning at high speed. Exchange coupling between recording and readout layers of an MSR-CAD disk can yield a quasi-circular sub-um aperture to effectively derive a readout signal from sub-um marks recorded on the disks. In this study, MSR-CAD is proved very suitable for "pulsed readout" because the readout CNR is 1.9dB larger than that with conventional DC method and the readout characteristics is thus clearly improved.