Laser speckle reducer

DBA can be integrated into tunable optical devices including laser speckle reducers and lenses, as described below. 

To reduce this problem, the company Optotune AG has developed and commercializes a DEA-based Laser Speckle Reducer (LSR) (Optotune 2015). The device functions in a similar way to a rotating difiiiser, although it is more compact and economical. A diffuser is mounted on an elastic membrane and set into eireular motion using four planar DBAs (actuating sectors), as illustrated in Fig. 12. 

Fig. 12 Working principle of the laser speckle reducer (a) no voltage is applied and the diffuser is centered (b) the upper actuating sector is active, translating the diffuser downward (c) fwo sectors are active which resulfs in a franslafion of fhe diffuser fo fhe bottom right comer (d) fhe left sector is active giving a franslafion fo fhe right. Alternation of fhe activation of fhe sectors resulfs info a circular motion of fhe diffuser...

Fig. 13 Optofune s laser speckle reducer LSR-3000 wifh an aperture of 5 mm. Attached fo fhe side of fhe recfangular sfmcfure fhe necessary elecfronics fo drive fhe LSR is visible...

A variety of applications of DEs have been reviewed covering a wide range of fields, ineluding robotics, tactile displays, fluid eontrol, sensors, and generators. While new design and applications are continuously been introduced, some of these applieation concepts are gradually been transitioned into commereial produets. Examples include capacitive sensors for human motion measurement produced by the eom-pany StretchSense, laser speckle reducers produced by the company Optotune, and headphones being developed by the company Artificial Muscle Inc. 

Laser projection systems have both a broader color spectmm and a higher lifetime compared to conventional illumination systems. However, lasers have the inherent problem of speckle on rough optical surfaces (e.g., a wall or a cinema screen), local interferences cause a grainy pattern of spots observable with a camera or naked eye. This effect causes noise in projected images but also reduces the resolution of measurement systems. 

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