ABSTRACT
This article details ways that machine learning and artificial intelligence technologies are being integrated in modern hearing aids to improve speech understanding in background noise and provide a gateway to overall health and wellness. Discussion focuses on how Starkey incorporates automatic and user-driven optimization of speech intelligibility with onboard hearing aid signal processing and machine learning algorithms, smartphone-based deep neural network processing, and wireless hearing aid accessories. The article will conclude with a review of health and wellness tracking capabilities that are enabled by embedded sensors and artificial intelligence.
ABSTRACT
We have made an ultra-thin (~2.26 µm) f/2.1 lens based on the Pancharatnam phase effect using the polarization holography alignment technique. This lens exhibits a continuous phase profile, high efficiency (>97%), and is switchable from having a positive focal length to a negative one by changing the handedness of input circularly polarized light. We analyzed its optical performance and simulated it as a gradient index lens for further comparison, and to discuss its bandwidth limitation. The conditions required for improving the performance and its low-cost fabrication method is discussed. Because of the nature of Pancharatnam devices and the demonstrated fabrication method, these results are applicable to a wide size range.
ABSTRACT
A device concept is presented to allow very large angle deflection of light passing through a transmissive device. Deflection of light, switchable between angles larger than ±60 deg, is shown to be possible with efficiencies approaching 100%.
ABSTRACT
It has been previously shown that a Pancharatnam phase device with a dual-twist structure can deflect light up to 60° with nearly perfect efficiency. This was beyond the limits previously assumed for these types of devices, which were considered to be optically similar to Raman-Nath gratings. In this paper we first consider the range of parameters that will allow for high efficiency and show the results for a structure that demonstrates 80° deflection. We then explore the light propagation through these devices to point out interesting intensity variations in the deflected mode of light as it traverses the deflecting layer. Finally, we explain the key to understanding the efficiency of these devices, which is not the typical parameters that are important for traditional diffractive devices, but rather the control of the polarization state of light. We provide a simple design approach for optimizing the twist angle and retardation for high efficiency.
ABSTRACT
A new approach to a polarization-independent twisted liquid-crystal (LC) structure, where phase difference between orthogonal eigenmodes is tuned to be an integer multiple of 2pi, is demonstrated with a numerical model. For select wavelengths, polarization-independent operation can be achieved by tuning the twist rate and thickness of the LC cavity. Applications can be found in polarization- independent switches and field sequential wavelength selection devices.
