We demonstrate a linear laser resonator incorporating a semiconductor optical amplifier and scanning filter for high repetition rate, broad wavelength, unidirectional scanning. The laser operates at up to 115 kHz repetition rates and demonstrates a tuning-speed-independent power of > 30 mW. We apply this laser to enable ultrahigh-speed optical frequency domain imaging of the dynamics of laser ablation of biological tissue. The imaging system acquires single longitudinal scans (A-lines) in 8.7 mu s and complete cross-sectional images comprising 575 A-lines at a rate of 200 frames per second. (c) 2006 American Institute of Physics.