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The development of vehicular LiDAR systems for adaptive cruise control, whereby the system identifies the distance of the vehicle in front and applies the breaks to slow or stop the vehicle automatically, has seen significant growth in recent times. More recently LIDAR’s have also been used in driver-less cars, where the system produces autonomous vehicles which can perform complex manoeuvers and drive in public with little or no input from a user.

Taking the same lead forward, Knight Optical is now offering BK7, one of the most widely used optical glasses available for use in the range from visible up to the near infrared making it ideal as a protective window for Wind LiDAR systems operating at 1500-1560 nm. The BK7 can offer an uncoated average transmission of 92% between 300 nm and 2000 nm. Additionally, it is a cost effective precision glass, part of the borosilicate family, which ensures a window fit for purpose.

LiDAR systems are used in monitoring wind speeds and directions on proposed and existing wind farm sites. This leads to wind farm optimizations through resulting increases in energy outputs. This gain in performance is achieved from the LiDAR system which is mounted to the nacelle of wind turbines automating the adjustment of blades to increase energy generations. The adjustments to the blades are due to the Doppler LiDAR system measuring the frequency shift of the backscattered light and thus calculating the wind velocity.

Airborne LiDAR systems are also used in surveying and for topographical measurements. Using the LiDAR system a Digital Terrain Model (DTM) or Digital Elevation Model (DEM) can be produced. These are typically 3D representations of a terrain’s surface. The system is typically integrated onto a plane which would then pulse a laser signal onto the terrain and dependent on the elevation of the surface, this would influence how long the pulse would return to the detector. These Airborne systems typically have protective windows which Knight Optical can provide with hydrophobic coatings and AR topcoat which allows for maximum signal return without the worry of pollution or condensation in the atmosphere.

LiDAR systems have also been the bane for many motorists where this technology have been utilized in traffic speed law enforcement. These systems are used as traffic speed law enforcement camera systems which can be found on motorways and major highways globally. Additionally they can be miniaturized into handheld systems which can accurately monitor the speed of single passing cars. These LiDAR systems are often integrated in conjunction with Automatic Number Plate Reading (ANPR) systems which allows for a traffic enforce to quickly determine the offending vehicle and to automate the ticketing enforcement process.

The BK7 comes in stock sizes from 5 mm to 75 mm diameter; between 1.5 mm – 8 mm thick. With edging down to smaller diameters, square and rectangular apertures, it is also available in custom shapes and sizes.

A typical spec for n-BK7 or equivalent Windows is:

• Material: N-BK7 or equivalent
• Diameter Tolerance: +0.0/-0.15 mm
• Length/Width Tolerance: +/- 0.10mm
• Thickness Tolerance: +/-0.10mm
• Transmission: Tavg=92% dependant on substrate thickness