title: Narrow linewidth operation of a spectral beam combined diode laser bar.
abstract: Our experiment is expected to provide an approach for realizing ultranarrow linewidth for a spectral beam combined diode laser bar. The beams of a diode laser bar are combined in a fast axis after a beam transformation system. With the help of relay optics and a transform lens with a long focal length of 1.5 m, the whole wavelength of a spectral combined laser bar can be narrowed down to 0.48 nm from more than 10 nm. We have achieved 56.7 W cw from a 19-element single bar with an M2of 1.4  (in horizontal direction)×11.6  (in vertical direction). These parameters are good evidence that all the beams from the diode laser bar are combined together to increase the brightness.
authors.forename: Zhanda
authors.initials: Z
authors.lastname: Zhu
authors.forename: Menghua
authors.initials: M
authors.lastname: Jiang
authors.forename: Siqi
authors.initials: S
authors.lastname: Cheng
authors.forename: Yongling
authors.initials: Y
authors.lastname: Hui
authors.forename: Hong
authors.initials: H
authors.lastname: Lei
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li