Apparatus and method for frequency conversion and mixing of laser light

A device for the nonlinear combination of laser light comprising:

• a) a tunable fiber laser light source which produces an energy beam along an optical path at a given frequency, wavelength, and intensity and includes thermal and piezoelectric elements for providing variable adjustment to at least the frequency of the energy beam;
• b) a nonlinear resonator, having four reflective mirrors, positioned along the optical path;
• c) a nonlinear optical crystal disposed in the optical path of the energy beam within the nonlinear resonator;
• d) a power amplifier operatively connected to the optical path before the nonlinear resonator, for amplifying the intensity of the energy beam;
• e) a first polarization rotator placed in the optical path after the laser light source and before the power amplifier and a second polarization rotator placed in the optical path after the power amplifier and before the nonlinear resonator;
• f) a feedback system operatively connected to the nonlinear resonator and the thermal and piezoelectric elements of the fiber laser light source using a Pound-Drever control scheme to adjust the frequency of the energy beam to match resonant frequency conditions within the nonlinear resonator, wherein the feedback system comprises a detector operatively connected to the nonlinear resonator and responsive to light within the resonator and a controller operatively coupled to the tunable fiber laser light source which is responsive to input from the detector for tuning the energy beam via the thermal and piezoelectric elements;
• and
• g) a phase modulator placed in the optical path of the energy beam before the amplifier and after the first polarization rotator, for modulating sidebands to the energy beam and coupled to the feedback system in accordance with the Pound-Drever control scheme.

A method for maintaining resonant conditions within a nonlinear resonator comprising the steps of:

• a) emitting a laser light from a tunable laser light source which produces the laser light at a given frequency, wavelength, and intensity, said laser light source including both thermal and piezoelectric tuning elements;
• b) modifying a physical parameter of the laser light in a nonlinear resonator having a nonlinear optical crystal operatively disposed therein;
• and
• c) measuring a physical parameter of the nonlinear resonator and adjusting at least one parameter of the laser light using both the thermal and piezoelectric elements of the tunable laser light source.