STAMPER, STAMPER TESTING METHOD, AND STAMPER TESTING APPARATUS

摘要

According to one embodiment, a stamper has a data area and servo area, and has concentric or spiral grooves formed in the data area. Phases αE and αH at which differential signal levels of the E- and H-polarized light are maximum when the data area is irradiated with a laser beam have a relationship represented by (αE+αH)≦̸270°