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Three laser resonators are demonstrated emitting at 1053 nm and pumped at 797 nm by volume Bragg grating-equipped diodes, achieving the highest reported efficiencies for Nd:YLF in a four-level system, to the best of our knowledge. A peak output power of 880 W is achieved by pumping the crystal with a diode stack of 1.4 kW of peak pump power.

When considering dynamically stable resonators, ring lasers are good choices because they have a stability interval that is twice as large as that of linear resonators and sensitivity to misalignment decreasing with pump power; however, the literature does not provide easy design guidelines. A ring resonator utilizing Nd:YAG side pumped by diodes allowed single-frequency operation. The output single-frequency laser had good output characteristics; however, the overall length of the resonator did not allow for building a compact device with low misalignment sensitivity and larger spacing between longitudinal modes which could improve single-frequency performance. Based on previously developed equations, which allow for ease of design of a ring dynamically stable resonator, we discuss how to build an equivalent ring resonator, aiming to building a shorter resonator with the same stability zone parameters. The study of the symmetric resonator containing a pair of lenses allowed us to find the conditions to build the shortest possible resonator.

Light sources are used in optofluidic devices for real-time system control and quantitative analysis of important process parameters. In this work, we present a random laser source using a hollow-core antiresonant reflecting optical waveguide (HC-ARROW) containing the gain media inside a reservoir to reduce dye bleaching, which is connected to microchannel waveguides to increase beam directionality. The device is pumped externally and emits a highly coherent and collimated laser beam.

Measurements of the bifocal, thermally induced lenses of a cw Nd:YAG laser were obtained. We observed four different focal lengths that are polarization and direction dependent. The focal lengths were used to design stable resonators with large fundamental mode filling in the laser gain medium. The beam is totally polarized in the desired direction even without an intracavity Brewster window. We developed a general approach for the optimization of single-lamp, cw-pumped Nd:YAG lasers. Up to 22 W of cw output power in the vertically polarized TEM(00) mode and 15 W in the horizontal polarization are obtained for moderate lamp currents. Also, we demonstrate mode locking with 56-ps pulse duration at 33 A of lamp current and up to 13 W of average output power.

We report an alternative experimental setup to laterally focus light at an angle of 90 deg relative to turbid, multiple scattering media, using preprocessing wavefront shaping. We compare the measured image quality to one obtained in the usual configuration for focusing light through turbid media, where focusing occurs behind the scattering sample. We demonstrate that the depth of focus in the lateral configuration is of the same order of the usual transversal one because both setups are designed to operate in the deep Fresnel zone. This result shows that this novel, versatile lateral configuration allows for effectively focusing around corners through multiple scattering samples.

Passive stable mode locking of a pulsed Nd:YAG laser was achieved with a long-decay-time saturable absorber in a coupled-cavity longitudinal scheme. In this configuration the saturable absorber (LiF:F(2) ) also behaves as an active medium in intracavity pumping and is the load for the Nd laser. This arrangement provides proper lasing conditions for the F(2) color centers so that the cavity photon lifetime of the color centers is much shorter than the cavity round-trip time of the Nd laser. In this way the Nd pulses are simultaneously Q switched and mode locked. The pulses show a stable temporal profile, with an envelope of 160 ns and a train of mode-locked pulses of less than 200-ps duration.