Practical diffraction-limited angle sensitive detectors

In this paper, we study a simple angle-sensitive detector for sensing optical beam deflections. This type of device is sought to replace position sensitive detectors commonly used with optical beam deflection techniques in a variety of applications. The main advantage is that the sensitivity is independent of the distance from the deflection point to the detector. To our knowledge this is the first practical design that approaches closely the diffraction limit to the sensitivity when sensing micro-deflections of a laser beam. The detector is based on reflection/transmission of the optical beam near the critical angle and uses a single antireflection layer. The sensitivity is nearly polarization independent. The temperature dependence of the device is discussed and a possible fabrication procedure of the device is analyzed.