Laser Homogenizers are optical components that are mainly used to average out any non-uniformities that could be present on an optical beam. There are two main types of laser homogenisers; the diffractive diffuser and the broadband diffuser. Diffractive diffusers are meant to be used with monochromatic light like that coming from laser systems. Broadband diffusers, on the other hand, can be used with polychromatic light sources.
Laser homogenisers in general stand out from the rest of diffuser components in that there is a tighter control over the resulting scattering angles. In fact, with laser homogenizers the output radiance can be circumscribed to a definite area which is defined by hard edges. In addition, the actual shape of that area can be of any desired geometrical shape or even an arbitrary shape. For the case of using diffractive laser homogenisers, the complexity that can be obtained from the output radiance pattern is even greater. In this case, the output pattern can also consist in areas with varying degrees of light radiance or the inclusion of intended hot spots immersed in an otherwise uniform area.
When using a laser homogenizer the mode content of the input laser mode will also have some influence on the final beam distribution. When the input beam is single mode, for instance the common TEM00 Gaussian mode, the presence of laser speckles is more noticeable. This is purely an interference effect and in many interesting applications, it turns out to be an effect that can be harnessed for different purposes such as metrology or moving sensors. If the laser beam is better described as a multimode laser beam, the speckle noise contrast is dramatically reduced. This is due to the fact that the speckle noise arising from each laser mode is independent from each other. The net result is an averaging of the speckle patterns that leads to very good uniformity. A radiance pattern with low noise is also very important for other types of applications.
Laser homogenisers have a myriad of applications across all industrial sectors that use laser systems. The most common application is in laser material processing in which the presence of the laser homogenizer boosts the efficiency of the laser system by adapting the beam radiance characteristics to the requirements of the specific environment. The same logic applies to all medical applications in which the optical beam from a laser system is also adapted to the medical environment.