Table of Contents
High-Power Narrow-Linewidth Laser Sources
High-power laser diodes have been developed for applications including solid-state laser pumping, fiber laser pumping, and material processing. The spectral bandwidth of high-power diodes typically spans the range of 3-5 nm. A narrow emission spectrum in the range of 0.1-0.5 nm and a smaller wavelength tolerance can be extremely beneficial for special applications such as the spin-exchange optical pumping (SEOP), which is of great importance in the field of nuclear physics, atomic physics, laser cooling, and neutron scattering.
Spectral Linewidth Narrowing Techniques for High-Power Diode Lasers
A variety of external cavity techniques has been developed to narrow the spectral line width of high-power diode lasers. Two types of gratings are used to form the external cavity. The diffraction grating external cavity provides a large tunable range of the center wavelength of ~10 nm. Meanwhile, the volume holographic grating (VHG) external cavity has a smaller footprint with a limited tunable center wavelength range of <0.5 nm. The resonant wavelength of a VHG can be precisely tuned with temperature control. Using a thick VHG (14-18 mm), one can narrow the spectral line width down to a few GHz (7-10 GHz) with output power exceeding tens of watts.
Beam Quality and Fiber Coupling Limitations
Due to the low beam quality of high-power broad-area laser diodes, it is difficult to effectively couple the laser power into a multi-mode fiber without special beam shaping treatment. High-power, narrow spectral line-width diode lasers are useful for optical pumping of alkali metal vapors. High-power, spectrally narrowed lasers with good stability are the key to the success of SEOP. However, these laser diode arrays are not the best choice for high-efficiency optical pumping applications.
Single-Frequency Fiber Lasers as an Alternative Solution
Achieving the narrow spectral linewidth that is required for a long coherence length makes for complicated and expensive lasers, although complexity and size can be somewhat reduced by going with a semiconductor laser design. Now, Optromix single-frequency high-power fiber Laser Irybus-SF-1030-X series offers a wide-range thermal wavelength tuning and optional active wavelength control. Irybus-SF-1030-X is a single-frequency high-power low noise 1030 nm – 1100 nm Yb-doped fiber laser. Its key advantage is an ultra-narrow line width (<100 kHz) based on a longitudinal single mode. Irybus-SF-1030-X comes with a piezoelectric tuning, internal and external wavelength modulations at kHz bandwidth for locking purposes.