Notch filtering using a multiple passband AOTF in the SWIR region

Abstract

A notch filtering operation was accomplished using a TeO₂ acousto-optic tunable filter (AOTF) with 16 simultaneous overlapping passbands in the shortwave infrared wavelength region. By switching off specific radio frequency signals applied to the AOTF, laser wavelengths corresponding to the inactive passbands are rejected, providing see-through capability with the remaining wavelengths. The rejection level was determined by leakage through the sidelobes of adjacent passbands, as was shown by theory and corresponding measurements. By switching off multiple passbands near the laser wavelength, the rejection level can be increased at the expense of reduced see-through capability. The AOTF imaging system used telecentric confocal optics that compensate for AOTF aberrations, which are severe at high sidelobe operation.

Calibration of Acousto-Optic Interaction Geometry Based on the Analysis of AOTF Angular Performance

“…When compared with traditional optical splitters, such as prism, grating and interferometer, it has advantages in terms of a large-angle aperture, high spectral resolution, arbitrary wavelength configuration, fast tuning speed and it does not require moving elements [ 2 , 3 ]. Therefore, it is widely used in many applications, such as spectral imaging [ 4 , 5 ], polarization analysis [ 6 , 7 ], stereoscopic imaging [ 8 ] and notch filtering [ 9 ], etc. In addition, in the case of monochromatic input light, AOTFs also have the abilities of spatial filtering and edge enhancement [ 10 , 11 ].…”

The Calibration Methods of Geometric Parameters of Crystal for Mid-Infrared Acousto-Optic Tunable Filter-Based Imaging Systems Design

“…The acousto-optic tunable filter (AOTF) has been widely applied in spectral imaging systems for remote sensing [ 1 , 2 ], spectral microscopy [ 3 , 4 ], three-dimensional detection [ 5 ], notch filtering [ 6 , 7 ], and edge enhancement [ 8 ] due to its advantages of a narrow bandpass, electric tunability, all-solid-state, fast response, large angular aperture, and wide spectral range. In particular, the flexible electric tunability makes AOTF spectral imagers the most promising candidates for identifying and tracking targets.…”

Analysis on the Influence of Incident Light Angle on the Spatial Aberrations of Acousto-Optical Tunable Filter Imaging

“…Moreover, it has many advantages, such as being electronically controlled with high speed, wide spectral range, and all-solid-state. As a result, AOTF staring imaging spectrometer is commonly used in spectral analysis [4], laser shaping [5,6], spectral microscopic [7,8], and many other fields [9][10][11][12][13]. Similarly, the advantages of AOTF make it very suitable for tracking and searching system.…”