Few cycle optics group

Finland Distinguished Professor (FiDiPro) Günter Steinmeyer and his group develop systems for phase-stable, intense femtosecond pulse generation at Tampere University of Technology. The group’s funding comes from the Academy of Finland thorough the FiDiPro-program and the ‘High-Field Science with Ultrafast Laser Sources’ project.

Figure 1: A key part of the phase stabilization scheme, showing the difference frequency crystal and some of the new frequencies generated, which lie in the visible and infrared

Research

The Few Cycle Optics group at ORC is pursuing a new avenue for the generation of phase-stable and intense femtosecond pulses. The laboratory, established in late 2008, is developing a pulse generation scheme consisting of a phase-stabilized amplified laser system with a subsequent pulse compression stage. The amplifier is seeded by a short-pulse oscillator that delivers 2.5-cycle pulses with nJ energy, which is then amplified to several microjoules of energy at reduced repetition rates of 100 kHz. To reestablish few-cycle pulse duration, the pulses will be recompressed subsequent to amplification. The phase-stable oscillator is currently being characterized, and the amplifier stage is under construction. Both sources will then directly be applied in experiments investigating nonlinear propagation in different types of fibers and photonic crystal structures, with particular emphasis on carrier-envelope effects.

Figure 2: The Ti:sapphire pulse oscillator in the lab (left), and a custom-made liquid nitrogen cooled amplifier chamber (right). The amplifier crystal is operated at low pressure, on the order of 10–6 mbar, to avoid icing on the surfaces, and specially designed Brewster angled windows minimize unwanted material dispersion while maximizing the aperture and largest operational angle. Figure 1: A key part of the phase stabilization scheme, showing the difference frequency crystal and some of the new frequencies generated, which lie in the visible and infrared.

Future prospects

Given its few-cycle pulse duration and its relatively high repetition rate, the developed source opens up a new window for application of phase stable pulses, particularly in high-field physics, a field that requires a massive amount of statistics and integration over many pulses. One of these applications lies in the field of atomic physics, exploring correlations in the simultaneous generation of two photoelectrons by virtue of the strong field. Both, oscillator and amplifier system therefore enable investigations to explore uncharted territory in nonlinear optics.

Recent publications by group members

1. A. Demircan, Sh. Amiranashvili, G. Steinmeyer, "Controlling light by light with an optical event horizon," Accepted to: Physical Review Letters (2011)
2. C. Brée, A. Demircan, G. Steinmeyer, "Saturation of the all-optical Kerr effect," to be published in April 2011 in Phys. Rev. Lett. (2011)
3. L. Orsila, C. Grebing, and G. Steinmeyer, “High repetition rate carrier-envelope phase stable laser system for ultrafast measurements,” Accepted to Optics Days 2011, May 12–13, 2011, Oulu, Finland (2011)
4. A. Härkönen, C. Grebing, J. Paajaste, R. Koskinen, J.-P. Alanko, S. Suomalainen, G. Steinmeyer, and M. Guina, “Mode-locked GaSb disk laser producing 384-fs pulses at 2 µm wavelength,” Accepted Electronics Letters (2011)
5. C. Brée, A. Demircan, J. Bethge, T.J. Nibbering, L. Berge, and G. Steinmeyer, “Filamentary pulse self-compression: The impact of the cell windows,” Phys. Rev. A 83, 043803 (2011)
6. J. Paajaste, S. Suomalainen, R. Koskinen, A. Härkönen, G. Steinmeyer, and M. Guina, “GaSb-based semiconductor saturable absorber mirrors for mode-locking 2 µm semiconductor disk lasers,” Accepted ISCS 2011, May 22 - 26. 2011, Berlin, Germany (2011)
7. G. Steinmeyer, “Carrier-envelope phase control with timing jitter below the atomic time scale,” Invited talk at ALT' 10, 18th International Conference on Advanced Laser Technologies, Sep. 11–16, 2010, Egmond an Zee, the Netherlands (2010)
8. A. Härkönen, J. Paajaste, S. Suomalainen, J.-P. Alanko, C. Grebing, R. Koskinen, G. Steinmeyer, and M. Guina, “Picosecond passively mode-locked GaSb-based semiconductor disk laser operating at 2 µm,” Opt. Lett. 35, No. 24, pp. 4090–4092 (2010)
9. A. Anderson, K.S. Deryckx, X.G. Xu, G. Steinmeyer, M.B. Raschke, “Few-Femtosecond Plasmon Dephasing of a Single Metallic Nanostructure from Optical Response Function Reconstruction by Interferometric Frequency Resolved Optical Gating,” Nano Lett. 2010, 10, pp. 2519-2524 (2010)
10. C. Grebing, S. Koke, and G. Steinmeyer, “Acousto-optical self-referencing of frequency combs,” Optics Days 2010 Proceedings, Optics Days 2010, May 6 - 7, 2010, Tampere, Finland (2010)
11. L. Orsila, C. Grebing, S. Koke, and G. Steinmeyer, “Characterization of the envelope and carrier-envelope phase of the ultrashort laser pulses,” Invited paper to 2010 International Symposium on Ultra-fast Phenomena and Terahertz Waves (ISUPTW 2010), Sep 11 - 16, Xian, China (2010)
12. C. Bree, A. Demircan, S. Skupin, L. Berge, and G. Steinmeyer, “Plasma Induced Pulse Breaking in Filamentary Self-Compression,” Laser Physics, 2010, Vol. 20, No. 5, pp 1107-1113 (2010)
13. L. Orsila, C. Grebing, and G. Steinmeyer, “Development of a 100 kHz repetition rate high power ultrashort-pulse carrier-envelope phase stable laser system,” Optics Days 2010 Proceedings, Optics Days 2010, May 6 - 7, 2010, Tampere, Finland (2010)
14. L. Orsila, C. Grebing, and G. Steinmeyer, “Towards a high power ultrashort-pulse carrier-envelope phase stable high repetition laser system,” Physics Days 2010, March 11 - 13, 2010, Jyväskylä, Finland, ISBN: 978-951-39-3834-5, p. 48 (2010)