  A frequency-stable, broadband laser is presented for experiments on trapped
ions. Since the design is based on widely available semiconductor optical
amplifier technology, similar lasers can be realized for virtually any
wavelength in the near-infrared, and the coherence properties and output power
allow for efficient second harmonic generation. No closed-loop frequency
stabilization for addressing Doppler- or naturally-broadened, dipole-allowed
transitions is needed, and the light source can be turned on and off during a
measurement cycle with sub-microsecond response time. As a case study, a
921.7-nm laser with an output power of 20mW and a linewidth of 10GHz is
realized, which is then frequency doubled to 460.9nm for excitation of
strontium as the first step in photo-ionization. The excitation efficiency is
compared to that achievable with a narrow-linewidth distributed Bragg reflector
laser as well as to theory.
