High Speed Imaging

Enhance camera performance with short-pulse laser illumination to freeze the motion of fast-moving subjects.

Visilase systems from Oxford Lasers combine high-speed cameras with pulsed lasers to offer the most powerful imaging systems in the world of R & D. The short-pulse lasers enhance camera performance by illuminating subjects with ultra-short pulses of light. Image blur is eliminated, even for subjects moving at high velocity. Laser light can be formed into a sheet (known as a lightsheet) to take a 2D slice through a turbulent 3D flow, for flow visualization.

Capturing a moment in time

Why use a pulsed (strobe) laser for high speed photography?

Conventional Spray Illumination

Both images were taken using the same spray subject, and the same high speed camera. For the upper movie a conventional, continuous light source was used. Even though the exposure time was only 1/4,500 second, there is motion blurring in the movie (you can't see the individual droplets).

Laser Spray Illumination

The lower movie was taken using laser strobe illumination from an Oxford Lasers copper vapor laser (CVL). The short pulse from the laser reduces the effective exposure time to 1/40,000,000 of a second (25 ns), and even the smallest droplets in the spray can be seen clearly - frozen in flight. The same technique can even freeze bullets in flight.

Applications of High Speed Imaging

Thousands of researchers around the world have used Oxford Lasers VisiLase systems to gain insight into their studies. VisiLase system have been used in applications including:

• Automotive Development - imaging fuel injection, engine airflows and airbag deployment
• Slow motion photography of the natural world from understanding river erosion to unraveling the mysteries of the flight of fruit flies
• Studies of sprays and aerosols from metered dose inhalers to hairsprays.
• Ballistics - freeze the motion of a bullet in flight
• High speed Schlieren photography
• Extensions to PIV, sizing, and viewing through flames, arcs and explosions
• Shock wave propagation and interaction studies

Lightsheets

Laser light can be formed into a thin sheet of light that can be used to take a 2D slice through a 3D flow. The example on the right shows the turbulent spray cloud from a pulmonary drug delivery device as it slows in a spacer device. Oxford Lasers has developed a unique fiber-optic delivered lightsheet - the FiberSheet, which can be used with copper vapor lasers and diode-pumped solid state lasers (subject to suitable fiber-delivery). The FiberSheet gives six times higher quality lightsheets than can be achieved in any other way.