Source: CASTECH Inc.

Understanding Acousto-Optic Tunable Filters

Operation Principle

An acousto-optic tunable filter (AOTF) is an optical filter controlled by radio frequency (RF) signals. When a sinusoidal RF signal is applied, diffraction occurs only within a specific range of optical frequencies, creating a bandpass filter. By varying the RF frequency, different optical frequencies can be addressed, allowing for tunable filtering of light.

Acousto-optic Filter Designs

There are different types of AOTFs designed for various applications. Collinear filters offer high efficiency but have a narrow acceptance angle. Non-collinear filters, on the other hand, provide larger acceptance angles but may require higher RF power. Some filters can work with unpolarized light, utilizing the birefringence of the crystal material.

Applications of Acousto-optic Tunable Filters

AOTFs are commonly used in multispectral imaging, laser microscopy, and spectroscopy. They enable rapid scanning for fast acquisition of spectral information, making them valuable in research and industrial applications. AOTFs are also utilized in wavelength-tunable light sources, optical fiber communications, and spectropolarimetry.

Conclusion

Acousto-optic tunable filters play a crucial role in modern optical systems, offering tunable filtering capabilities for various applications. By understanding their operation principles and different designs, researchers and engineers can leverage the versatility of AOTFs in advancing optical technologies.

Source: Scientific Research Publishing
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