Apparatus and method for pumping of a weakly absorbing lasant material

A laser system, comprising:

• a) first laser means comprising a first optical cavity and a first lasant material which is located in said first optical cavity and which when pumped by diode laser pumping means produces laser light of a first wavelength along an optical path;
• b) an etalon which is at least partially located in said first optical cavity, which is formed from a sensitized second lasant material of sufficient thickness to absorb said laser light from said first lasant material to achieve Optimum Output Coupling with said first laser means and to function as the output coupler for said first laser means, which has one face to receive said light from said first laser means, and which has an opposite face, said faces lying generally perpendicular to said optical path;
• and
• c) cavity means, having an axis which is generally coaxial with said optical path, for forming at least part of a laser cavity for said sensitized second lasant material to lase at a second wavelength, said first lasant material being selected to have sufficiently low absorption losses at said second wavelength and said second lasant material being selected to have sufficiently low absorption losses at said first wavelength such that there is a net gain in said first lasant material and in said second lasant material.

A solid state laser system, comprising:

• a) a plano-convex and doped crystal which is selected from the group consisting of YAG, YVO.sub.4 and YLF, which is located in a laser cavity, which emits laser light when pumped by a laser diode source, which has a flat face and an opposite convex face, and which is essentially transparent to light at a predetermined wavelength;
• and
• b) output means for said laser cavity comprising a sensitized glass lasant material which is located in said laser cavity, which has a thickness to absorb said laser light from said convex face of said crystal for Optimum Output Coupling to said crystal, which has a thickness which is thin relative to the corresponding dimension of said plano-convex crystal, which emits laser light at said predetermined wavelength, which contains at least one rare earth element selected from the group consisting of Yb and Er, which has one face which is located adjacent to said crystal, and which has an opposite face, said flat face of said crystal and said opposite face of said glass being coated from high reflection of said laser light from said crystal, said convex face of said crystal and said one face of said glass being anti-reflection coated for said laser light from said crystal, said one face of said glass being coated for high reflection at said predetermined wavelength, and said opposite face of said glass being coated for reflection at said predetermined wavelength.

A laser system, comprising:

• a) a laser source having an output at a first wavelength;
• b) a laser cavity comprising
• reflecting means for reflecting light at a second wavelength and at said first wavelength,
• a sensitized glass lasant material which is located between said reflecting means and said laser source, which is sufficiently thick to absorb said laser light at said first wavelength for Optimum Output Coupling to said output of said laser source, which substantially functions as an output coupler for said laser source, which emits laser light at said second wavelength, which has one surface which faces said source, and which has an opposite surface which faces said reflecting means, and
• means, adjacent to said source, for reflecting into said one surface of said lasant material light at said one wavelength and at said second wavelength;
• and
• c) optical isolator means for receiving said output of said laser source and transmitting said output to said one surface of said lasant material and for isolating said laser source from said laser light at said second wavelength.

A method for pumping a relatively weakly absorbing lasant material, comprising the steps of:

• (a) selecting a first lasant material and a weakly absorbing second lasant material which have sufficiently low losses at a secondary laser wavelength and at a primary laser wavelength respectively, such that a net gain is achievable in each material;
• (b) locating said first lasant material in a first laser cavity and producing laser light at said primary wavelength;
• (c) locating said second lasant material to receive said laser light at said primary wavelength, and pumping said second lasant material with said laser light at said primary wavelength to produce laser light at said secondary wavelength;
• and
• (d) adjusting the amount of said second lasant material to absorb light at said primary wavelength for Optimum Output Coupling to said light from said first lasant material, such that said second lasant material substantially functions as an output coupler for said first laser cavity.

A laser apparatus, comprising:

• a) a first laser cavity which is resonant at a primary wavelength;
• b) a first lasant material which is located in said first laser cavity to produce optical radiation at least at said primary laser wavelength;
• and
• c) a second lasant material which is optically pumped by said optical radiation from said first lasant material, which absorbs optical radiation at said primary laser wavelength in an amount to achieve Optimum Output Coupling to said optical radiation from said first lasant material, which is at least partially located in said first laser cavity, which functions as the output coupler of said first laser cavity, and which lases at a secondary laser wavelength, wherein said first lasant material is selected to be essentially transparent at said secondary laser wavelength.

A laser apparatus, comprising:

• a) a first laser cavity;
• b) a first lasant material located in said first laser cavity to produce optical radiation at one or more primary laser wavelengths;
• c) a second lasant material located in said first laser cavity and having a transmission of radiation at one of said primary optical wavelengths which is substantially equal to the reflectivity for Optimum Output Coupling for said first lasant material, said second lasant material when absorbing optical radiation at said one primary optical wavelength producing a population inversion in said second lasant material and optical gain at a secondary laser wavelength;
• and
• d) a second laser cavity which is resonant at said secondary laser wavelength, and which has output coupling means for said secondary optical wavelength, said second lasant material being located in both said first laser cavity and said second laser cavity.