Optically pumped semiconductor ring laser

A laser, comprising:

• at least first and second composite layer-structures, each thereof including a multilayer semiconductor gain-structure surmounting a mirror-structure;
• said mirror-structures being arranged as resonator mirrors of a first unidirectional ring-resonator with said gain-structures of said composite layer-structures located in said first ring-resonator;
• an arrangement for energizing said gain-structures to cause fundamental laser-radiation to circulate in said ring-resonator;
• a first optically nonlinear crystal located in said first ring-resonator and arranged to convert said fundamental laser-radiation to second-harmonic radiation;
• a second optically nonlinear crystal located in said first ring-resonator and arranged to mix said fundamental and second-harmonic radiations to provide third-harmonic radiation;
• and
• a second ring-resonator arranged to circulate said second-harmonic radiation therein, said first and second ring-resonators being arranged to be partially coaxial, with resonator axes thereof following a first common path through said first optically nonlinear crystal and a second common path through said second optically nonlinear crystal.

A laser, comprising:

• first, second, third, and fourth composite layer-structures, each thereof including a multilayer semiconductor gain-structure surmounting a mirror-structure;
• said mirror-structures being arranged cooperative with first and second mirrors as resonator mirrors of a first unidirectional ring-resonator with said gain-structures of said composite layer-structures located in said ring-resonator;
• an arrangement for energizing said gain-structures to cause fundamental laser-radiation to circulate in said first ring-resonator, said mirror-structures and said mirrors being numbered in the direction of circulation of said fundamental radiation in said ring-resonator, with said mirrors between said fourth and first composite layer-structures;
• and
• a first optically nonlinear crystal located in said ring-resonator between said first and second mirrors and arranged to convert said fundamental laser-radiation to second-harmonic radiation.

A laser, comprising:

• first, second, third, and fourth composite layer-structures, each thereof including a multilayer semiconductor gain-structure surmounting a mirror-structure;
• said mirror-structures being arranged cooperative with first and second mirrors as resonator mirrors of a first unidirectional ring-resonator with said gain-structures of said composite layer-structures located in said first ring-resonator;
• an arrangement for energizing said gain-structures to cause fundamental laser-radiation to circulate in said first ring-resonator, said mirror-structures and said mirrors being numbered in the direction of circulation of said fundamental radiation in said first ring-resonator, with said mirrors between said fourth and first composite layer-structures;
• and
• a first optically nonlinear crystal located in said first ring-resonator between said second and third mirror structures and arranged to convert said fundamental laser-radiation to second-harmonic radiation;
• a second optically nonlinear crystal located in said first ring-resonator between said first and second mirrors and arranged to mix said fundamental and second-harmonic radiations to provide third-harmonic radiation;
• and
• a second ring-resonator arranged to circulate said second-harmonic radiation therewithin, said first and second ring-resonators being arranged to be partially coaxial, with resonator axes thereof following a first common path through said first optically nonlinear crystal and second common path through said second optically nonlinear crystal.

A laser, comprising:

• a first laser-resonator including a gain medium;
• an arrangement for energizing said gain-medium to cause fundamental laser-radiation to circulate in said first ring-resonator;
• a first optically nonlinear crystal located in said first laser-resonator and arranged to convert said fundamental laser-radiation to second-harmonic radiation;
• a second laser-resonator in the form of a ring-resonator formed by a plurality of resonator mirrors and arranged to circulate said second-harmonic radiation therein said second-harmonic radiation following a round-trip path in said second laser-resonator, said second laser resonator being arranged such that the length of said round-trip path is adjustable, said first and second laser-resonators being arranged to be partially coaxial, with resonator axes thereof following a common path through said first optically nonlinear crystal, and said second laser-resonator is arranged such that a portion of said circulating second-harmonic radiation is delivered therefrom;
• a device for adjusting the length of said round trip path of said second laser-resonator;
• and
• an electro-optical arrangement including at least one photodetector for receiving and analyzing said second-harmonic radiation and deriving therefrom an electrical signal representative of the resonant condition of said second laser-resonator for said second-harmonic radiation circulating therein, said electrical signal being used to cause said round trip path-length adjusting device to adjust said round-trip path length to maximize resonance of said-harmonic radiation circulating in said second-laser resonator.