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generation of CEP stabilized pulses

  • Record setting CEP stability for generation of isolated attosecond pulses
  • CEP4 – revolutionary direct feed-forward technology with zero phase slip
  • Sub-7 fs, multi-mJ CEP stabilized pulses


Spectra-Physics pioneered the development of Ti:Sapphire ultrafast lasers. The advancements of this technology have revolutionized the field of molecular dynamics by opening the door to time-resolved experiments in the femtosecond regime. Spectra-Physics Ti:Sapphire lasers are now utilized in most of the world's ultrafast research laboratories.

In recent years, in order to observe and control electronic dynamics occurring on sub-atomic time and length scales in matter, scientists have developed techniques to generate attosecond pulse trains and isolated attosecond pulses in the XUV or soft-X-ray spectral region. Spectra-Physics, through its acquisition of Femtolasers, has further expanded its ultrafast technology to deliver the highest performance few-cycle lasers for attoscience, including with Carrier-Envelope Phase (CEP) stabilization for generation of isolated attosecond pulse.


The development of CEP stabilized lasers started more than 15 years ago when Femtolasers pioneered the technology and released the first system commercially available, shortly after the scientific community had introduced the necessary fundamental concepts (Reichert et al., Optics Communication 172, p. 59-68 (1999) | Telle et al., Applied Physics B 69, p. 327-332 (1999)). This is what Femtolasers defines as CEP1.

In 2003, the first fully CEP-stabilized amplified ultrashort pulses were obtained at the Institute for Photonics, Technical University of Vienna, employing Femtolasers Femtopower™ compact PRO amplifier (Baltuska et al., Nature 421, p. 611-615 (2003)).


In 2004, Femtolasers introduced its 2nd generation of CEP-stabilized systems, CEP2, as a result of two innovative technologies: the Rainbow™ ultrafast oscillator with sub-7fs pulse durations and spectral bandwidth greater than 300 nm and the Femtolasers proprietary (Fuji et al., Optics Letters 29, Issue 6, p. 632-634 (2004)) monolithic Difference Frequency Generation (DFG) technique for CEP stabilization. The Rainbow outstanding performance immediately proved spectral broadening in a fragile nonlinear fiber obsolete for CEP stabilization. Instead, its direct exceptionally broad spectrum underwent a collinear DFG process which provided outstanding beat signal quality for CEP stabilization of the pulse train. This allowed the CEP stability to break the two hour barrier.


In order to respond to the continually evolving requirements from the attosecond scientific community, Femtolasers revealed in 2008 its exclusive CEP3 generation of ultrafast laser systems. The concept behind CEP3 was based on independent CEP-stabilization of both the Rainbow seed oscillator and the Femtopower amplifier (LaserFocusWorld, April 2008; Femtolasers exclusive technology) and allowed the generation of amplified CEP stable pulses for more than a full working day, with a CEP drift of less than 200 mrad (rms). These pulses were further compressed to sub-7 fs duration with energies of up to 2 mJ with the hollow fiber and dispersive mirror based compressor Kaleidoscope™ (Anderson et al., Proc. of SPIE 7578, 75781T, 2010).


Self-referenced feed-forward approach allows CEP stabilization of the oscillator virtually over an unlimited time, with chosen phase slip.

Already leader in the field of CEP stabilization, Femtolasers remained a pioneer at the forefront of the ultrafast laser community and developed tomorrow’s CEP stabilization scheme.

In 2012, we introduced our latest technique: CEP4 – a direct feed-forward approach. The CEP drift is corrected on-the-fly, after the free-running oscillator. The inherently stable CEP allows for superior reliability which does not come at the cost of CEP performance. Zero phase slip, i.e., a train of pulses with identical waveform, is now as easy to obtain as any other slip rate. CEP4 improves every aspect of CEP stabilization.

CEP4 does not affect the laser performance, requires no complicated locking electronics, and has already been demonstrated with sub-12 attoseconds residual timing jitter, below the atomic unit of time (S. Koke et al., Nature Photonics 4, p. 462-465 (2010) | Femtolasers patent). CEP4 is a revolutionary step forward, resolving the most critical issues of any feedback-based CEP stabilization (F. Lücking et al., Optics Letters, accepted (2012).

Today, with the latest sealed ultrabroad bandwidth oscillator Rainbow 2 CEP4, the Femtopower amplifier and the Kaleidoscope compressor, Spectra-Physics is the only commercial company capable of delivering ultrafast amplifier systems suitable for isolated attosecond pulse generation.

Rainbow 2

Plug and play few-cycle oscillators