Diode laser reliability in dynamic laser speckle application: Stability and signal to noise ratio

Abstract The biospeckle, or dynamic laser speckle, is used as a potential tool to monitor activity in many biological and non-biological materials from agriculture to medicine, and it is usually based on the use of He-Ne and diode lasers, the latter of which has great potential to be embedded in portable equipment. Some queries about the stability of the diode laser were raised, such as the real influence of the mode hopping phenomenon as a drawback in solid-state devices in comparison to the well-known He-Ne lasers, and thus we decided to test it . In addition, we present an alternative way to enhance the stability and the signal-to-noise ratio of the information using a relative index rat…