High repetition rate passively Q-switched laser for blue laser based on interactions in fiber

A laser apparatus comprising:

• a Neodymium-doped lasing material, wherein the lasing material includes a first-surface that is substantially transparent to a pump radiation and substantially reflective to laser radiation generated by an interaction between the pump radiation and the Neodymium-doped lasing material, wherein the laser radiation is characterized by a vacuum wavelength corresponding to an atomic transition from the 4F3/2 level to the 4I9/2 level of Neodymium in the lasing material, the lasing material further having a second surface that transmits at least a portion of the laser radiation;
• and
• a passive Q-switch optically coupled to the second surface of the lasing material;
• and
• wherein the lasing material and the Q-switch are configured to produce pulses of the laser radiation;
• wherein the pulses are characterized by a pulse length of greater than zero and less than about 1.5 nanoseconds and a pulse repetition rate greater than about 100 kHz;
• wherein the Q-switch includes a saturable Bragg reflector (SBR);
• wherein the SBR includes a substrate, semiconductor mirror stack having alternating high and low refractive index layers, a quantum well stack having between about 3 and about 15 quantum wells, and a dielectric overcoat;
• wherein the semiconductor mirror stack is disposed between the substrate and the quantum wells;
• wherein the quantum well stack is disposed between the semiconductor mirror stack and the dielectric overcoat;
• wherein the dielectric overcoat includes alternating layers of SiO2 and HfO2;
• and
• wherein the dielectric overcoat has a reflectivity of between about 87% and about 96% at the wavelength of the laser radiation from the Neodymium-doped lasing material.

A passively Q-switched laser (PQSL), comprising:

• a source of pump radiation;
• a Neodymium-doped lasing material, wherein the lasing material includes a first-surface that is substantially transparent to the pump radiation and substantially reflective to laser radiation characterized by an electronic transition from the 4F3/2 level to the 4I9/2 level of Neodymium in the lasing material, the lasing material further having a second surface that transmits at least a portion of the laser radiation;
• and
• a passive Q-switch optically coupled to the second surface of the lasing material;
• wherein the source of pump radiation, lasing material and Q-switch are configured to produce pulses of laser radiation characterized by a wavelength corresponding to an electronic transition from the 4F3/2 level to the 4I9/2 level;
• wherein the pulses are characterized by a pulse length of greater than zero and less than about 1.5 nanoseconds and a pulse repetition rate greater than about 100 kHz;
• wherein the lasing material is Nd:YVO4;
• and
• wherein the Neodymium concentration in the lasing material is greater than about 1% and less than about 3%.

An apparatus for producing blue light comprising:

• a neodymium-doped cladding-pumped fiber device for amplifying laser radiation;
• an optical harmonic generator optically coupled to the fiber device for increasing a frequency of the laser radiation to produce a blue output radiation;
• and
• a passively Q-switched laser (PQSL) optically coupled to the neodymium-doped cladding-pumped fiber device, wherein the PQSL is configured to produce the laser radiation, the laser radiation having a harmonic that is blue, whereby the harmonic generator interacts with the laser radiation to produce blue light,
• wherein the PQSL includes:
• a source of pump radiation;
• a Neodymium-doped lasing material, wherein the lasing material includes a first-surface that is substantially transparent to the pump radiation and substantially reflective to laser radiation characterized by a by an electronic transition from the 4F3/2 level to the 4I9/2 level of Neodymium in the lasing material, the lasing material further having a second surface that transmits at least a portion of the laser radiation;
• and
• a passive Q-switch optically coupled to the second surface of the lasing material;
• wherein the source of pump radiation, lasing material and Q-switch are configured to produce pulses of the laser radiation characterized by a wavelength corresponding to an electronic transition from the 4F3/2 level to the 4I9/2 level;
• wherein the pulses are characterized by a pulse length of greater than zero and less than about 1.5 nanoseconds and a pulse repetition rate greater than about 100 kHz;
• wherein the lasing material is Nd:YVO4;
• and
• wherein the Neodymium concentration in the lasing material is greater than about 1% and less than about 3%.