Abstract: A high-density read-only optical disc, and an optical disc apparatus and method using the same. The apparatus and method record data on a lead-in area of a high-density read-only optical disc such as a BD-ROM (Blu-ray disc ROM (Read Only Memory)) in the form of pre-pit strings associated with an HFM (High-Frequency Modulated) groove applied to a BD-RW (Blu-ray Disc Rewritable). Moreover, the apparatus and method continuously apply the same tracking servo operation to an entire area of the same high-density read-only optical disc or rewritable optical disc. Therefore, the apparatus and method can simplify an algorithm for controlling a plurality of tracking servo operations, and avoid an increased size of the optical disc apparatus.

Abstract: The present invention relates to a highly repetitive laser employing a rotating wedge, and more specifically, a laser employing a rotating wedge which can provide a laser beam having a uniform spatial intensity profile with a high repetition rate. The highly repetitive laser of the invention is characterized by positioning a rotating wedge between a main resonator and a focusing lens to change the point in which a laser beam emitted from the main resonator is focused, in a laser which comprises a main resonator consisting of a laser medium, a passive Q-switching material and partially reflective mirrors and an auxiliary resonator consisting of a focusing lens and a cell.