A polarising filter that lets more light pass through has been developed by engineers at the University of Utah. It could enable LCD display devices that consume less power (as the backlight would not need to be as bright), as well as low-light cameras.
A polariser typically blocks between 60% and 70% of light, as it only allows through horizontally- or vertically-aligned light. The rest is reflected back or absorbed and the resulting image is darker.
The new filter was created by etching a silicon wafer with nanoscale pillars and holes using a focused gallium-ion beam. Almost 30% more light can pass through compared to a standard polariser, as the blocked light is converted to the desired polarised state. Up to 74% light pass-through has been achieved, although the eventual goal is for 100% pass-through.
The concept polariser is 20µm² and was tested with infrared light. However, there are plans to increase the size and test it with visible light. Marketable applications could be available in 5-10 years.