A directly diode pumped Yb:KYW regenerative amplifier is demonstrated to study a novel approach to enhance the gain
bandwidth. Two gain spectra are combined by using the crystal directions Nm and Np of Yb:KYW.
We demonstrate compact ultrahigh resolution OCT systems for <i>in vivo</i> studies, with broadband light sources based on a commercially available Nd:Glass femtosecond laser and nonlinear fiber continuum generation. <i>In vivo</i> OCT images of hamster cheek pouch and human skin acquired at 4 frames per second and with 5.5 μm axial resolution are presented. These systems are robust, compact and portable.