Pulsed Yb³⁺-doped fiber laser operating at 1011 nm by intra-cavity phase modulation

Compact fs ytterbium fiber laser at 1010 nm for biomedical applications

Ytterbium-doped fiber lasers (YDFLs) working in the near-infrared (NIR) spectral window and capable of high-power operation are popular in recent years. They have been broadly used in a variety of scientific and industrial research areas, including light bullet generation, optical frequency comb formation, materials fabrication, free-space laser communication, and biomedical diagnostics as well. The growing interest in YDFLs has also been cultivated for the generation of high-power femtosecond (fs) pulses. Unfortunately, the operating wavelengths of fs YDFLs have mostly been confined to two spectral bands, i.e., 970-980 nm through the three-level energy transition and 1030-1100 nm through the quasi three-level energy transition, leading to a spectral gap (990-1020 nm) in between, which is attributed to an intrinsically weak gain in this wavelength range. Here we demonstrate a high-power mode-locked fs YDFL operating at 1010 nm, which is accomplished in a compact and cost-effective package. It exhibits superior performance in terms of both short-term and long-term stability, i.e., <0.3% (peak intensity over 2.4 μs) and <4.0% (average power over 24 hours), respectively. To illustrate the practical applications, it is subsequently employed as a versatile fs laser for high-quality nonlinear imaging of biological samples, including two-photon excited fluorescence microscopy of mouse kidney and brain sections, as well as polarization-sensitive second-harmonic generation microscopy of potato starch granules and mouse tail muscle. It is anticipated that these efforts will largely extend the capability of fs YDFLs which is continuously tunable over 970-1100 nm wavelength range for wideband hyperspectral operations, serving as a promising complement to the gold-standard Ti:sapphire fs lasers.

1016nm all fiber picosecond MOPA laser with 50W output

This paper presents an all fiber high power picosecond laser at 1016 nm in master oscillator power amplifier (MOPA) configuration. A direct amplification of this seed source encounters obvious gain competition with amplified spontaneous emission (ASE) at ~1030 nm, leading to a seriously reduced amplification efficiency. To suppress the ASE and improve the amplification efficiency, we experimentally investigate the influence of the gain fiber length and the residual ASE on the perforemance of the 1016 nm amplifier. The optimized 1016 nm MOPA laser exhibits an average power of 50 W and an optical conversion efficiency of 53%.