As a composite laser rod capable of satisfying the positional stability
and output stability of a laser beam, a laser rod in which a laser active
element is doped is intimately inserted into a hollow portion of a
non-doped ceramic pipe that has a crystal structure the same as the laser
rod followed by baking so as to remove a gap and strain at an interface
between the laser rod and the ceramic pipe after the baking further
followed by polishing a surface of the ceramic pipe to form a ceramic
skin layer, and thereby a composite laser rod is formed. In the composite
laser rod, an influence due to fluctuation in the cooling capacity of
cooling water or a heat sink is averaged by a non-doped skin layer,
temperature fluctuation of the laser rod is suppressed, and an influence
of vibration from the cooling water or a cooling fan can be suppressed.
When the refractive index of the laser rod is made higher than that of
the ceramic pipe, a high efficiency oscillation can be realized, and
furthermore when the thermal conductivity of the ceramic pipe is made
higher than that of the laser rod, the thermal lens effect can be
alleviated.