Optical filters for LiDAR application




Lidar systems use optical filters to selectively allow specific wavelengths of light to pass through while blocking unwanted wavelengths. These filters are crucial in Lidar systems as they help to eliminate background noise and interference from other light sources.

There are different types of optical filters that can be used in laser Lidar systems, depending on the specific application requirements. Some common types include:

      1. Bandpass Filters: These filters allow a specific range of wavelengths to pass through while blocking all other wavelengths. Bandpass filters are often used in Lidar systems to narrow down the emitted laser wavelength and filter out ambient light.

     2. Notch Filters: Notch filters, also known as rejection filters, are designed to block a specific wavelength range while allowing all other wavelengths to pass through. These filters are useful in eliminating unwanted laser emission lines or spectral artifact noise.

     3. Neutral Density Filters: Neutral density filters are used to attenuate the intensity of the laser beam without altering its spectral content. They reduce the laser power while maintaining the same wavelength distribution.

     4. Interference Filters: Interference filters use layers of dielectric coatings to selectively transmit or reflect specific wavelengths. These filters create constructive and destructive interference to block certain wavelengths while transmitting others.

     5. Narrow Bandpass Filters: Edge filters are designed to transmit narrow wavelength bands while blocking both shorter and longer wavelengths. They are commonly used in Lidar systems to isolate specific laser lines.


The choice of the optical filter depends on the desired laser wavelength, the required spectral bandwidth, and the level of background noise that needs to be suppressed in the Lidar system.