Adjustment of a tunable external-cavity laser is simplified by
incorporating a mount that includes a base, a main body, a reflecting
surface, a diffracting surface and a hinge coupling the main body to the
base. The laser additionally includes a light source, a converging lens
located to receive light from the light source, a tuning mirror and a
pivoting arm on which the tuning mirror is mounted. The main body is
bounded in part by two plane, external surfaces orthogonal to a common
reference plane and angularly separated from one another by an angle. The
reflecting surface has a spatial orientation defined by one of the
external surfaces and is arranged to receive light from the lens. The
diffracting surface has a spatial orientation defined by the other of the
external surfaces, and diffracts light received from the reflecting
surface towards the tuning mirror. The hinge is located opposite the
angle and parallel to the reference plane.