Ultra-short pulse characterization using a reference laser pulse

We propose a novel and simple technique to determine the temporal profile of ultra-short laser pulses uniquely from a measured auto-correlation spectrum. It involves forming a sequence of two laser pulses spaced by a time delay τ, the first one being the pulse to be characterized and the second one a reference pulse. This sequence is sent through any device that measures the Fourier transform (FT) magnitude of the sequence's temporal profile, such as a classical optical auto-correlator. This FT magnitude is then processed analytically using a novel algorithm to retrieve the temporal profile of the sample pulse unambiguously. The reference pulse can be either an unchirped symmetric pulse or any pulse with a known profile. This requirement does not constitute a limitation because once the temporal profile of a given pulse has been characterized by this technique, even though it may not be an unchirped symmetric pulse, this pulse can be used as the reference pulse to determine the profile of any other ultra-short pulse. Compared to other measurement techniques, such as frequency-resolved optical gating, our technique is much faster and simpler, in terms of both experimental and computational complexity. Simulations also show that the profile recovery is quite accurate even in the presence of strong noise on the measured FT magnitude.

[1]  Michel J. F. Digonnet,et al.  Improved technique to determine second-order optical nonlinearity profiles using two different samples , 2004 .

[2]  Nobuharu Nakajima.  Reconstruction of a real function from its Hartley-transform intensity , 1988 .

[3]  G. Mourou,et al.  Laser ablation and micromachining with ultrashort laser pulses , 1997 .

[4]  Yeshaiahu Fainman,et al.  Femtosecond pulse imaging: ultrafast optical oscilloscope , 1997 .

[5]  D. Kane,et al.  Using phase retrieval to measure the intensity and phase of ultrashort pulses: frequency-resolved optical gating , 1993 .

[6]  E A Swanson,et al.  Femtosecond transillumination tomography in thick tissues. , 1993, Optics letters.

[7]  J P Heritage,et al.  Encoding and decoding of femtosecond pulses. , 1988, Optics letters.

[8]  P. Peterson,et al.  The pulse shape of a passively Q-switched microchip laser , 2000 .

[9]  Sophie LaRochelle,et al.  Pulse shaping with a phase-shifted fiber Bragg grating for antisymmetric pulse generation , 2001, SPIE LASE.

[10]  Jean-Claude Diels,et al.  Ultrashort Laser Pulse Phenomena: Fundamentals, Techniques, and Applications on a Femtosecond Time Scale , 1996 .

[11]  Michel J. F. Digonnet,et al.  Detailed analysis of inverse Fourier transform techniques to uniquely infer second-order nonlinearit , 2004 .

[12]  Christian Spielmann,et al.  Generation of intense 8 fs laser pulses. , 2003, Optics express.

[13]  Michel J. F. Digonnet,et al.  Inverse Fourier transform technique to determine second-order optical nonlinearity spatial profiles , 2003 .

[14]  Gregory E. Hall,et al.  CW autocorrelation measurements of picosecond laser pulses , 1980 .

[15]  K. Miura,et al.  Writing waveguides in glass with a femtosecond laser. , 1996, Optics letters.

[16]  Rick P. Millane,et al.  Analytic properties of the Hartley transform and their implications , 1994 .

[17]  Rick Trebino,et al.  Measuring spatial chirp in ultrashort pulses using single-shot Frequency-Resolved Optical Gating. , 2003, Optics express.

[18]  Michel J. F. Digonnet,et al.  Simplified inverse Fourier transform technique to measure optical nonlinearity profiles using reference sample , 2004 .