Image quality in laser-diode-based diffractive scanning systems

摘要

Abstract: Laser scanning systems using diffractive scanning mechanisms must address the spectral purity of their laser sources. If the source is a laser diode, then certain spectral behavior characteristics must be modeled and accounted for as part of the design. Ability to directly modulate laser diode drive current, while generally a hallmark of this type of device, can be a key contributor to focal spot quality degradation due to the diffractive mechanism interacting with the laser modal transients. In this paper the system image quality as a function of the transient and steady state source spectral characteristics as well as diffractive scanner type is discussed. Methods are described which can achromatize these scanning systems to varying degrees by performing filtering or compression on the diode's emission spectrum. !20