Yoonchan Jeong

We have demonstrated a highly-efficient cladding-pumped ytterbium-doped fiber laser generating 1.36 kW of continuous-wave output power at 1.1 mum with 83% slope efficiency and near diffraction-limited beam quality. The laser was end-pumped through both fiber ends and showed no evidence of roll-over even at the highest output power, which was limited only by available pump power.

We discuss continuous-wave single-frequency master- oscillator power-amplifier (MOPA) sources based on ytterbium- doped fibers (YDFs) with particular attention to their recent advances and our experimental results. This includes a 402-W plane-polarized MOPA source and a 511-W random-polarized MOPA source. In these MOPAs, the final-stage high-power amplifier operates with high efficiency of 70%-80%, and a high gain of over 20 dB in a near diffraction-limited beam. We report at least 7-dB enhancem

We have demonstrated a high-power and high-efficiency erbium:ytterbium (Er:Yb) codoped fiber laser that produces 297 W of continuous-wave output at 1567 nm. The slope efficiency with respect to the launched pump power changed from 40% to 19% at higher output power due to the onset of Yb colasing at 1067 nm. However, the Yb colasing was essential for the suppression of catastrophic pulsation at high pump powers that otherwise results if the Yb-band gain is allowed to build up. Spectroscopic chara

A ytterbium-doped fibre laser with up to 1 kW of continuous-wave output power at 1.09 µm with a slope efficiency of 80% and a good beam quality (M2=3.4) is reported. The fibre was pumped by two diode-stack sources launched through opposite ends. No undesirable roll-over was observed in output power with increasing pump power.

We have demonstrated a highly efficient cladding-pumped ytterbium-doped fiber laser, generating <TEX>$&gt;$</TEX>2.1 kW of continuous-wave output power at 1.1 μm with 74% slope efficiency with respect to launched pump power. The beam quality factor (<TEX>$M^2$</TEX>) was better than 1.2. The maximum output power was only limited by available pump power, showing no evidence of roll-over even at the highest output power. We present data on how the beam quality depends on the fiber parameter, based

We present a single-frequency, single-mode, plane-polarized ytterbium-doped all-fiber master oscillator power amplifier source at 1060 nm generating 264 W of continuous-wave output power. The final-stage amplifier operated with a high gain of 19 dB and a high conversion efficiency of 68%. There was no evidence of rollover from stimulated Brillouin scattering even at the highest output power, and the maximum output was limited only by the available pump power.

We present a cladding-pumped single-frequency, single-mode erbium:ytterbium codoped fiber master-oscillator power amplifier source generating up to 151 W of continuous-wave output power at 1563 nm with 33% slope efficiency and 20 dB gain. This source was also tunable and had a stable operation range of 1546 to 1566 nm at an output power level in excess of 125 W. The doped fiber exploited a large-core design for improved power handling and mitigation of stimulated Brillouin scattering. There was

We demonstrate a highly efficient cladding-pumped ytterbium-doped fiber laser. It generated up to 1 kW of continuous-wave output power at 1.1μm with 80% slope efficiency and a good beam quality, when end-pumped through both fiber ends.

Advances in imaging technologies have led to a high demand for ultracompact, high-resolution image sensors. However, color filter-based image sensors, now miniaturized to deep submicron pixel sizes, face challenges such as low signal-to-noise ratio due to fewer photons per pixel and inherent efficiency limitations from color filter arrays. Here, we demonstrate a freeform metasurface color router that achieves ultracompact pixel sizes while overcoming the efficiency limitations of conventional ar

An electrically controllable fiber-optic filter for broad-band rejection has been demonstrated by periodically poling a liquid-crystalline core in a hollow-core fiber by means of an external long-period-combed electrode. The periodically poled liquid-crystalline core in a period of 483 μm couples the fundamental core mode to the leaky cladding modes. A maximum loss dip of approximately 15-nm bandwidth and 6 dB band rejection has been obtained for a nonpolarized light with a combed 250-V external

The authors report a widely tunable and highly efficient cladding-pumped erbium-ytterbium codoped large-core fiber laser, generating up to 43 W of output power at /spl sim/1.5 μm with a narrow linewidth (0.16-nm full-width at half-maximum) and a good beam quality (M <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> <1.7). By use of a tunable narrow-band fiber Bragg grating, the laser wavelength was tuned from 1532 to 1567 nm, limited upwards b

We demonstrate a cladding-pumped single-mode plane-polarized ytterbium-doped fiber laser generating 633 W of continuous-wave output power at 1.1 microm with 67% slope efficiency and a polarization extinction ratio better than 16 dB. The laser is end pumped through both fiber ends and shows no evidence of roll-over, even at the highest output power, which is limited only by the available pump power.