Laser diode end pumped Nd:YAG single mode laser

In a laser apparatus for producing single-mode linearly polarized, coherent radiation at optical wavelengths:

• a laser diode for generating a beam of coherent optical pumping radiation;
• an optical resonator having an optical axis therein;
• a solid member of generally non-birefringent lasant material disposed within said optical resonator on the optical axis of said resonator;
• means for directing the beam of optical pumping radiation into said solid member of lasant material as disposed within said optical resonator for optically pumping same to produce an optical gain bandwidth having a characteristic peaked gain curve and for exciting a plurality of resonant axial modes of said optical resonator with coherent, optical radiation at a plurality of optical wavelengths;
• said optical resonator being dimensioned to be sufficiently short such that the optical path length within said optical resonator and through said solid member of lasant material is such that essentially only two non-polarized adjacent optically resonant, axial modes of said resonator will lase when centered in frequency on opposite sides of the peak of the gain curve within the optical resonator containing said optically pumped member of lasant material;
• and
• means for stressing said member of lasant material to produce therein a stress with a predominant component transverse to the optical axis of said optical resonator to produce a stress related birefringence of said lasant material causing linear polarization of the two excited axial modes of said optical resonator along an axis normal to the direction of the stress in said member of lasant material and to produce a third excited axial mode of optical resonance of said optical resonator, said third mode of resonance being linearly polarized parallel to the direction of the applied stress and having a resonant optical wavelength inbetween the optical wavelengths of said first two excited optical resonant modes, whereby the energy of the third excited optical resonant mode can be separated by a polarization sensitive device from the energy of the first two excited optical modes to produce a single-mode, linearly polarized output.

In a laser apparatus for producing linearly polarized coherent radiation at optical wavelengths:

• means for generating a beam of coherent optical pumping radiation;
• an optical resonator having an optical axis therein;
• a solid member of generally non-birefringent lasant material disposed within said optical resonator on the optical axis of said resonator;
• means for directing the beam of optical pumping radiation into said solid member of lasant material as disposed within said optical resonator for optically pumping said solid member of lasant material;
• clamp means for stressing said member of lasant material to produce therein a stress related birefringence;
• and
• said clamp means including means for contacting one side of said solid member of lasant material along a pair of parallel relatively closely spaced lines of contact and including means for contacting said solid member of lasant material along a third line of contact generally diametrically opposed to said first two lines of contact and said third line of contact being generally parallel to said first two lines of contact, whereby the lasant material is transversely stressed to produce the stress-related birefringence therein.