Solid state laser and wavelength conversion laser

A solid-state laser comprising:

• a partial reflection mirror and a total reflection mirror that have the same curvature radius and that constitute a resonator;
• two rod-shaped solid-state laser elements arranged in a symmetrical pattern along an optical axis of a laser beam between the partial reflection mirror and the total reflection mirror;
• and
• a convex lens having a focal length “f” and a 90 degree polarization rotator that are arranged along the optical axis of the laser beam between the two solid-state laser elements,
• wherein
• a distance between the lens and each of centers of the respective solid-state laser elements is substantially 2f.

A solid-state laser comprising:

• a partial reflection mirror and a total reflection mirror that constitute a resonator;
• two rod-shaped solid-state laser elements which are arranged in a symmetrical pattern along an optical axis of a laser beam between the partial reflection mirror and the total reflection mirror, which each have a length L0 and a refractive index n0, and which have mutually-opposing end faces machined at a curvature radius Ra so as to act as convex lenses;
• and
• a 90 degree polarization rotator that are arranged along the optical axis of the laser beam between the two solid-state laser elements, wherein
• the curvature radius is expressed as
• R
• a
• =
• n
• 0
• -
• 1
• 2
• 
• n
• 0
• ·
• L
• 0
• ,
• and a distance L3 between the two solid-state laser elements is expressed as
• L
• 3
• <
• L
• 0
• n
• 0
• .

A solid-state laser comprising:

• a plurality of periodic constituent elements of resonators, each of which has two rod-shaped solid-state laser elements arranged along an optical axis of a laser beam between a partial reflection mirror and a total reflection mirror that constitute a resonator and that are plane mirrors;
• two convex lenses, each having a focal length “f,” and a 90 degree polarization rotator that are arranged along the optical axis of the laser beam between the two solid-state laser elements, a distance between the two lenses being smaller than 2f, and a distance between a center of each of the solid-state laser elements adjacent to the respective lenses and each of the adjacent lenses being substantially “f”,
• wherein
• a distance between the center of the solid-state laser element adjacent to the partial reflection mirror and the partial reflection mirror is equal to a distance between the center of the solid-state laser element adjacent to the total reflection mirror and the total reflection mirror;
• and
• a distance between the centers of the solid-state laser elements adjacent to each other between the periodic constituent elements of the respective resonators is equal to a value that is twice as large as the distance between the partial reflection mirror and the center of the adjacent solid-state laser element.

A solid-state laser comprising:

• a plurality of periodic constituent elements of resonators, each of which has two rod-shaped solid-state laser elements arranged along an optical axis of a laser beam between a partial reflection mirror and a total reflection mirror that have an identical curvature and that constitute a resonator;
• two convex lenses, each having a focal length “f”, and a 90 degree polarization rotator that are arranged along the optical axis of the laser beam between the two solid-state laser elements, a distance between the two lenses being smaller than 2f, and a distance between a center of each of the solid-state laser elements adjacent to the respective lenses and each of the adjacent lenses being substantially “f”,
• wherein
• a distance between the center of the solid-state laser element adjacent to the partial reflection mirror and the partial reflection mirror is equal to a distance between the center of the solid-state laser element adjacent to the total reflection mirror and the total reflection mirror;
• a distance between the centers of the solid-state laser elements adjacent to each other between the periodic constituent elements of the respective resonators is equal to a value that is twice as large as the distance between the partial reflection mirror and the center of the adjacent solid-state laser element;
• and
• a lens having a focal length R/2 is positioned at an intermediate location between the periodic constituent elements of the mutually-adjacent resonators when the curvature radius of the partial reflection mirror is taken as R.

A solid-state laser comprising:

• a plurality of periodic constituent elements of resonators,
• wherein a ring resonator is built from a partial reflection mirror and a plurality of total reflection mirrors that are plane mirrors;
• wherein each of the resonators has two rod-shaped solid-state laser elements arranged along an optical axis of a laser beam within the resonator and two convex lenses, each having a focal length “f”, and a 90 degree polarization rotator that are arranged along the optical axis of the laser beam between the two solid-state laser elements;
• wherein a distance between the two lenses is smaller than 2f;
• wherein a distance between a center of each of the solid-state laser elements adjacent to the respective lenses and each of the adjacent lenses is substantially “f”;
• and
• wherein the periodic constituent elements of the resonator are arranged such that an equal distance exists among all of the periodic constituent elements of the respective mutually-adjacent resonators.