Colorectal Robotic-Assisted Surgery in Children. Long-Term Outcomes and Pitfalls.

Background: Colorectal surgical procedures may benefit from a minimally invasive approach in children, although there are few studies.

Methods: A retrospective, single-centre observational study was conducted on paediatric patients who underwent colorectal robotic-assisted surgery between 2011 and 2022.

Results: A total of 50 patients (33 male; 17 female) were included, with a median age of 4.

Nested-ring doping for highly efficient 1907 nm short-wavelength cladding-pumped thulium fiber lasers.

Cladding-pumped Tm-doped fiber lasers operating below 1950 nm have difficulty matching the high-efficiency, power-scalable output that can be achieved at longer wavelengths. This challenge arises due to the strong three-level behavior at short wavelengths and strong competition from higher-gain long wavelength emission. In this Letter, we demonstrate a nested-ring fiber design in which a highly doped Tm ring is embedded within a larger undoped core.

47 W continuous-wave 1726 nm thulium fiber laser core-pumped by an erbium fiber laser.

The high-power, short-wavelength operation of a thulium-doped silica fiber laser at 1726 nm has been demonstrated in a core-pumped monolithic (all-fiber) resonator configuration, in-band pumped by a high-power erbium-only fiber laser operating at 1580 nm. The thulium fiber laser yielded 47 W in a single-spatial-mode output beam for 60-W absorbed pump power. The corresponding slope efficiency, with respect to an absorbed pump power of 80%, compares favorably with the theoretical maximum (Stokes) efficiency of 91.

Tunable holmium-doped fiber laser with multiwatt operation from 2025 nm to 2200 nm.

The emission band of holmium-doped silica fibers extends beyond 2200 nm, which means these lasers have the potential of covering considerable parts of the atmospheric transmission window between ∼2100   and 2250 nm. However, efficient operation toward 2200 nm is challenging due to absorption in fused silica at the laser wavelength. Here we present a holmium-doped fiber laser specifically targeting long-wavelength operation.

Radially and azimuthally polarized nanosecond Yb-doped fiber MOPA system incorporating temporal shaping.

We report an Yb-doped fiber master-oscillator power-amplifier (MOPA) system with the capability of selectively generating doughnut-shaped radially and azimuthally polarized beams with user-defined temporal pulse shapes. The desired output polarization was generated with the aid of a nanograting spatially variant half-waveplate (S-waveplate). The latter was used to convert the linearly polarized fundamental (LP) mode output from the preamplification stages to a doughnut-shaped radially polarized beam prior to the power amplifier stage.