Amplitude Stabilization of a THz Quantum-Cascade Laser using a Photonic Integrated Circuit

We demonstrate a method to stabilize the output power of a ∼3.3-THz quantum-cascade laser (QCL) using a photonic integrated circuit, consisting of a racetrack resonator (RTR) coupled to a QCL ridge waveguide. Amplitude stabilization was achieved for >300 seconds, without perturbation to the emission spectrum, by dynamically adjusting the electrical bias to the RTR, and hence the coupling between the QCL and RTR

An Empirical Investigation into the Difficulties Experienced by Visually Impaired Internet Users

In this paper, an empirical based study is described which has been conducted to gain a deeper understanding of the challenges faced by the visually impaired community when accessing the Web. The study, involving 30 blind and partially sighted computer users, has identified navigation strategies, perceptions of page layout and graphics using assistive devices such as screen readers. Analysis of the data has revealed that current assistive technologies impose navigational constraints and provide limited information on web page layout. Conveying additional spatial information could enhance the exploration process for visually impaired Internet users. It could also assist the process of collaboration between blind and sighted users when performing web-based tasks. The findings from the survey have informed the development of a non-visual interface, which uses the benefits of multimodal technologies to present spatial and navigational cues to the user