A new method for improvement of laser pulse characteristics in a Nd:YAG passive Q‐switch laser is presented. The method is based on the external controlled small‐signal transmissivity of a passive Q‐switch crystal. Cr4+:YAG and LiF:F−2 crystals are investigated. A high flexibility in choosing laser pulse parameters is obtained. © 1996 Society of Photo−Optical Instrumentation Engineers.