A tunable laser comprises multiple reflectors defining a resonant cavity, and an optical gain medium positioned within the resonant cavity. One of the reflectors is a programmable micromirror array that acts as a tunable blazed diffraction grating providing continuous tuning of a single resonant mode over a wavelength gain region of the gain medium. The continuous tuning is provided by altering the micromirror array to shift, in synchrony, a resonant mode wavelength of the resonant cavity and a reflection filtering peak of the array. The array comprises a plurality of micromirror elements that can be controlled to independently move in a direction perpendicular to the plane of the array. In one embodiment, each element has a V-shaped movable mirror. In another embodiment, each element has a flat or slightly-tilted horizontal mirror and a vertical or nearly-vertical mirror orthogonal to the horizontal mirror producing a corner-cube-like reflection.