Innovative Ultrafast Laser Solutions

Innovative Ultrafast Laser Solutions

PhaseShifterTM Laser Beam Synchronized to X-Ray Synchrotron Beam

Recently, a Clark-MXR Model IMPULSETM "PhaseShifter" 20 Watt Yb-doped fiber laser was installed at the Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung (BESSY) – demonstrating yet another new application for this ground-breaking technology: synchronizing the sub-250 fs optical pulse of IMPULSETM in both frequency and phase with the X-Ray beam from the synchrotron at BESSY in Berlin, Germany.

Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung BESSYThe electronics of IMPULSETM were used to synchronize its optical pulse train (red in the photo) to the synchrotron pulse train (blue) at a repetition rate of 1.25 MHz with a temporal jitter that is detector-limited to less than one picosecond. The time of arrival of the two pulse trains at a target can be shifted electronically with respect to each other.

This video shows how easy it is to change the phase of the laser pulses relative to the X-Ray pulses. The pulses from BESSY are produced in batches, with a small break, a single pulse, then another break followed by another batch of X-Rays. The process repeats itself continuously. The customer wanted to synchronize the output of IMPULSETM to the single pulse between the two breaks at a repetition rate of 1.25 MHz.

X-Ray pulses from BESSY and optical pulses from IMPULSETM are detected using a plastic scintillator and a photomultiplier. The scintillator produces a small flash of light when an X-Ray pulse passes through it. The photomultiplier detects this flash of light and turns it into an electrical signal. The photomultiplier also detects the pulse from IMPULSETM, so the user simply sends a very small amount of a pulse from IMPULSETM into the photomultiplier along with the X-Ray pulse from the synchrotron. It is easy to distinguish between the two pulses because the optical pulses from the laser are on the order of 220fs in pulse width while the X-Ray pulses have a pulsewidth of about 10 ps.

This video shows the ease at which the phase between the two pulse trains can be controlled to very high precision. BESSY’s measurement equipment has a pulsewidth resolution of 1 ps. The phase of the pulses from IMPULSETM could be accurately controlled to within the measurement resolution of BESSY’s detection equipment.

This short video shows the ease with which it is possible to synchronize IMPULSETM with BESSY. The difference in frequency between IMPULSETM and BESSY’s reference frequency is displayed at the start of this video. After "pushing the green button" IMPULSETM synchronizes its frequency and phase to the reference from BESSY - as shown in this video by the fact that the frequency difference is zeroed out.

Download the article.