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Temperature Feedback Control for Long-Term Carrier-Envelope Phase Locking

Reference Number: 09-11

Inventors: Zenghu Chang, Chenxia Yun, Shouyuan Chen, He Wang, and Michael Chini

For reliable applications of the carrier-envelope phase (CEP) stabilized pulses, low phase noise and excellent long-term stability are crucial. Researchers in the J.R. Macdonald Laboratory at Kansas State University have discovered and demonstrated a patent-pending method for greatly extending the typical stabilization time of the oscillator. Without adding new optical elements or disturbing the operation of the oscillator, this scheme is compact, easy to operate, and economical. The researchers have achieved CEP stabilization lasting for 12 hours on a daily basis and more than 34 hours on occasion, which is 3-4 times longer than the typical locking time without temperature feedback control.
The long-term CEP lock is required in the single attosecond experiments since such experiments usually take many hours to collect sufficient counts to suppress the statistical noise. It is common practice to obtain CEP stable pulses from the oscillator by locking the carrier-envelope offset frequency (fCEO ) through modulating the pump power with an acousto-optic modulator (AOM). Due to the change of environmental conditions in laser laboratories, fCEO may drift out of AOM locking range, which limits fCEO stabilization time. The K-State research team demonstrated a temperature feedback scheme to compensate the slow fCEO drift and extend the CEP stabilization duration.
  • Extending oscillator CEP stabilization by 3-4X
  • No additional optical elements
  • Economical
Fig 1.

Fig. 1. (a) 34 hours CEP stabilization achieved by employing the double feedback loop; the blue curve shows the AOM driving voltage output; the pink curve shows the temperature of the crystal; (b) Error signal from locking electronics.
  • Frequency metrology
  • Attosecond physics
  • Coherent control experiments with CEP stabilized few cycle pulses
  • High harmonic generation using oscillator beam
Patent Status
  • U.S. patent #8,228,961 issued on July 24, 2012.

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