Patent ID: 7455957

Claim:
A method for producing a blazed holographic grating, the method comprising executing in sequence the following steps: a) a resist pattern preparing step of subjecting a photoresist layer provided on a substrate to holographic exposure to form a sinusoidal or half-sinusoidal resist pattern on the substrate; b) a first ion beam etching step of irradiating the substrate having a sinusoidal or half-sinusoidal resist pattern formed thereon with an ion beam obliquely at an angle that is substantially identical to a desired blaze angle in the presence of a first etching gas having a high selectivity ratio to execute etching until a height of the resist pattern decreases to a predetermined ratio of an initial value; and c) a second ion beam etching step of irradiating the substrate with an ion beam in the direction corresponding to substantially half a vertical angle of a vertex of a grating groove pattern in the presence of a second etching gas having a smaller selectivity ratio than that of the first etching gas to execute etching until the remaining resist pattern disappears completely, whereby a sawtooth grating groove pattern is engraved directly on the substrate.