A tunable laser including: a reflecting mirror; a partially transmitting mirror; a gain medium energized by a pump source; a pair of mirrors surrounding the gain medium, a first prism and a second prism located between the gain medium and the reflecting mirror; the first prism receives radiation from the gain medium and disperses the radiation to the second prism; the second prism receives and directs the radiation towards an optical element which filters the spatially dispersed radiation based on the position to the second prism, the radiation resonates between the reflecting mirror and the partially transmitting mirror; the second prism is placed on a stage moved by a linear motor such that a desired center wavelength is obtained by moving the second prism to a position so as to allow radiation having the desired center wavelength to resonate between the reflecting mirror and the partially transmitting mirror.