A method of enhancing wavelength tuning performance in an external cavity laser includes providing a diffractive focusing element, emitting light into the cavity of the laser at a range of angles relative to an optical axis of the cavity, and diffractively focusing the light back onto the optical axis at a wavelength-dependent focal distance using the diffractive focusing element. The method further includes confining the diffractive focusing to a high dispersivity portion of the diffractive focusing element. In various embodiments, the confining may include offsetting the diffractive focusing element radially relative to the optical axis, or selectively blocking a portion of the light emitted into the cavity at emission angles less than a threshold emission angle.