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Sequentially timed all-optical mapping photography (STAMP) is an effective tool for observing ultrafast and non-repetitive events. In the classical design of STAMP, the spatial resolution of the acquired images is different in two directions, severely limiting the scalability of STAMP. Here, by introducing an asymmetric optical design, we make the slicing mirror locate in the hybrid plane of the system, i.e., the image plane in the direction of the short edge, while the Fourier plane is in the direction of the long edge. This avoids the loss of the high-frequency components of the images and hence offers the possibility to further extend the frame number of the system.

We demonstrate a high-power blue diode laser operated at 447 nm combining laser diodes using an optical fiber bundle. As many as 127 diode lasers at 447 nm were coupled into 400 μ m/0.22NA fibers using an aspherical lens group with different focus lengths. The bare fibers were mechanically bundled through high temperature ultraviolet adhesive after the coatings of the 127 fibers were stripped. The diameter of the fiber bundle was 6 mm. The total output power of such a bundle was 152 W with electro-optical conversion efficiency of 27.56% and the RMS power instability was less than ± 1% within 3 h.

A simple and compact linear resonator green laser at 532 nm is generated by intracavity frequencydoubling of a diode-side-pumped acousto-optically (AO) Q-switched Nd:YAG laser at 1064 nm. Two acoustooptic Q-switches were placed orthogonally with each other to improve the hold-off capacity. As high as 214 W of continuous-wave (CW) and 154 W of quasi-continuous-wave (QCW) output power at 1064 nm were obtained when the pumping power was 1598 W. The type Ⅰ phase-matched BBO crystal was used as the nonlinear medium in the second harmonic generation. A green laser with an average output power of 37 W was obtained at a repetition rate of 20 kHz and a pulse width of 54 ns, which corresponds to pulse energy of 1.85 mJ per pulse and a peak power 34.26 kW, respectively.

We demonstrated a high power laser at 532 nm by frequency-doubling of an acousto-optically Q-switched and side-pumped Nd:YAG laser at 1064 nm using a compact linear cavity. The average output power of the pulsed fundamental laser at 1064 nm was as high as 299 W. The laser employed two acousto-optic Q-switches placed orthogonally with each other to improve the hold-off capacity. Through intracavity frequency doubling with a type II non-critically phase-matched LBO crystal, a 165 W average power of the frequency-doubled output at 532 nm was generated with a repetition rate of 20 kHz and pulse width of 160 ns, which corresponds to a pulse energy of 8.25 mJ and a peak power of 51.6 kW, respectively. The output power of the green laser was very stable and the stability at various output powers was measured. The RMS instability was ±1.4% when the output power of 532 nm was 135 W. After coupling the 165 W output power at 532 nm into an 800 μm fiber, the final output from the optical fiber was 149 W with a coupling efficiency of 90.3%.

The beam quality mismatch of laser diode stacks in both axes limits many direct applications for fiber or solid laser pumping and material processing. In this paper, a one-step cutting-rotating beam shaping system has been designed to homogenize the beam quality of two polarization-multiplexing laser diode stacks. Coupling laser diode stacks consisting of eight bars into a standard fiber with a core diameter of 600 μm and an NA of 0.22 is achieved. The simulative result shows that the system will have an output power over 1056 W. By using the technique, the production of compact and high brightness fiber-coupling diode lasers can be directly used for laser cladding and laser surface hardening processes.