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Coherence study on the image properties of holographic display

Coherence study on the image properties of holographic display

 

Coherence properties of different light sources and how they affect the image quality of holographic display are investigated. Temporal coherence is related to the intrinsic spectrum bandwidth of the light source, while spatial coherence can be affected by the size of the light source and propagation distance in use. These two coherence properties are measured for various light sources of diode-pumped solid-state (DPSS) laser, laser diode (LD), light emitting diode (LED), super luminescent light emitting diode (sLED) and micro light emitting diode (mLED) in different settings, together with the quality of the holographic reconstructed images. Although the image sharpness and speckle are related to both coherence parameters, our results and subsequent analysis show that the spatial coherence can be linked directly to the image sharpness and the temporal coherence to the speckle. This will provide a quantitative way not only to optimize the image quality between uniformity and sharpness but also to determine the safety power level for different light sources when viewing the produced images by human eyes directly.

 

Introduction of CPDS

Centre for Photonic Devices and Sensors (CPDS) is in the Photonics area of the Electrical Engineering Division, with a research focus embracing photonic and sensing devices, functional materials and their integration at system level.

We aim to address future societal needs with new system functionalities through invention of novel device architectures based on in-depth understanding of basic material properties.

There is a wide range of activities within the group, including phase-only holography and its applications, high brightness multi-stable colour reflective displays, tunable dielectric materials and devices for radio frequencies, liquid crystal on silicon (LCOS) device development, and novel sensors.

As well as conducting highly focused studies, we also specialise in the development of demonstrators for business exploitation and commercialisation. This is facilitated by multi-disciplinary expertise within the group and by our highly experienced team approach. Some of the outcomes from the group have been successfully transferred to our industrial collaborators for production.