Speckle imaging and diffuse correlation spectroscopy are analytical techniquex that leverages the coherence of a laser to identify areas where are objects are moving and where they are stationary [1-5]. When an object is illuminated with a coherent laser source, an interference pattern of reflected light is generated, which is known as speckle.
However, when an object is moving, the speckle pattern is disrupted. Thus, by comparing consecutive recorded images of an object, stationary objects and regions of motion can be distinguished. Given this it is possible to image moving objects such as blood flow in arteries and veins (i.e., areas with speckle are stationary, while areas with low speckle are moving).
IPS has found that highly coherent single-frequency sources are not the best choice for this application space. The higher the coherence, the larger the speckle pattern which results in a reduced image contrast. For this reason, wavelength stabilized multi-mode lasers are the ideal choice for this application.
Furthermore, since this is an illumination technique, it is important to have a uniform “flat-top” intensity profile which can be obtained with various types of round or rectangular core optical fiber which can be customized for specific applications.