The TIMEWARPTM autocorrelator is based on the proven Michelson interferometer configuration for splitting an incoming pulse train into two daughter trains which produce the autocorrelation signal when recombined on a detector. It is manufactured under exclusive license from the University of St. Andrews. A varying delay is provided by mounting one mirror on the central cone of a small loudspeaker driven at 18Hz.

The two pulse trains are recombined on an GaAsP LED* where 2 photon absorption occurs and the autocorrelation appears as an electrical signal. This technique has a number of significant advantages over conventional methods for measurement of Ultrafast pulses:

- No PMT / non-linear crystal combination required

- Simple to set up and align

- Compact - takes minimal space on table

- Insensitive to input polarisation

The Timewarp E750 autocorrelator consists of an optical head and a control unit plus external mains power supply. The optical head houses the scanning interferometer and fits directly onto an M4 post mount for quick and easy alignment to the laser being measured using an alignment jig that is included.   All of the optics in this interferometer are reflective apart from the beamsplitter, which is very thin to reduce the effects of dispersion on the incoming pulse.

The path lengths in the two arms of the interferometer need to be equal and this can be adjusted via a recessed hex head screw in the side of the unit. Recessed adjustments are also provided for the fixed mirror tilt so that the two beams can be overlapped and recombined on the detector. The small size of the interferometer and high mechanical stability of the unit mean that only minor adjustments to the alignment will be necessary after installation in order to display an autocorrelation trace.

The Controller unit houses the drive circuitry for the loudspeaker which generates the scan in the interferometer plus the signal conditioning. Front panel controls are provided for adjustment of the amplitude of the scan and the phase of the signal fed into the oscilloscope. All connections are on the rear panel including 12VDC input, connection to the optical head (cable supplied), Trigger and Signal connections to the oscilloscope and the sync. input and output connectors for daisy-chaining two units together.

Options and Accessories

Other operating wavelengths available

Optical Head - Front Panel	Optical Head - Rear Panel

Controller - Front Panel	Controller - Rear Pane

*  Patent No   USA 6195167