Tuning Fork Resonant Choppers
Tuning fork choppers are the most reliable choppers. They have an infinite lifetime. They can work in high temperature, ultra high vacuum and cryogenic environments. Tuning fork choppers are used for chopping light, plasma, X-ray and laser light.
They are low cost - especially in larger quantities, compact size, lightweight and have virtually unlimited life. This make the tuning fork choppers suitable for dedicated applications, OEM, built into an instrument or system, and for small, portable and hand-held systems. Tuning fork chopper that meets MILITARY SPECIFICATIONS are available as a special order.
A tuning fork chopper is a ONE FIXED FREQUENCY electromechanically driven light chopper. Vanes, attached to moving tines, modulate a light beam. The chopper operates at the natural resonant frequency established by the effective mass of the moving assembly and the spring constant of the tines. The one FIXED chopping frequency is chosen from a range (from 10 Hz to 6 KHz).
Apertures up to 15mm are practical in the lower frequencies (under 100 Hz), apertures of 0.5mm at 3 KHz and apertures 0.2mm at 6 KHz. If the beam size is limiting the chopper frequency, consider focusing the beam.
The motion amplitude of the chopper is inversely proportional to its frequency. You can find examples of the frequency amplitude relationship in the table below. Dark or bright vanes are standard; mirrors, lenses or gratings are optional. The standard operating temperature is -40 deg C to +65 deg C.
