Detection of the angle-of-arrival of an optical beam by means of interference optical filters for free-space optical...

We propose a method for estimating the angle-of-arrival of an optical beam, which is based on angle-dependent properties of interference optical filters. One-filter and two-filter configurations for beam angle detection in one plane were investigated experimentally. By using off-the-shelf interference filters and a laser beam with a 4 nm broad spectrum at a 1030 nm center wavelength, an angle detection range of 1.6°-2.3° was achieved with an angle detection uncertainty standard deviation of <0.2% of the total beam angle detection range. The performance of the proposed beam angle detection method was compared with that of the segmented detector method under conditions of air turbulence. It was found that the proposed method is more resistant to turbulence-caused beam distortions and allows determination of the beam angle with higher precision.