Femtosecond Pulse Shaping

Adaptive Compression and Measurement of Ultrashort Laser Pulses

BSI's technology applies to lasers that produce ultrashort (femtosecond) pulses. Femtosecond (10-15s) lasers have important properties that make them desirable for a number of applications, such as cutting without thermal damage, and imaging through scattering media. Producing these ultrashort pulses is difficult. Making sure the pulses stay short until they reach the target is also difficult and requires highly trained laser experts. BSI's proprietary technology, multiphoton intrapulse interference phase scan (MIIPS®), provides automatic measurement and compression of the pulses so that they arrive at the target with the shortest possible duration. The adaptive pulse compression and measurement are done at a level of accuracy and resolution that is higher than what could be achieved by a laser expert using conventional optics. In most settings, this technology enables applications of ultrashort pulses by eliminating manual tweaking, which is one of the most difficult and time-consuming aspects of dealing with femtosecond lasers. The systems offered by BSI combine the concepts published in the scientific literature [1-5] and hundreds of hours from our experts perfecting a turn-key solution that works for all of our customers.

What is Multiphoton Intrapulse Interference?

Linear optical interference is a well-understood physical process that is responsible, for example, for the observation of rainbows in soap bubbles, and makes the spot where a laser pointer shines appear "sparkl" Multiphoton intrapulse interference (MII) is a quantum mechanical interference that is similar to linear interference; however, it involves non-linear processes such as two-photon excitation, second harmonic generation, difference frequency mixing, etcetera. In MII, one is able to obtain constructive or destructive interference by changing the phase between the interfering photons. The word "intrapulse" implies that the interfering photons come from the same pulse. In MII, one controls the interference of photons with different frequencies that are within the spectrum of the pulse. Using MII one can design shaped pulses that suppress certain non-linear optical processes through destructive interference. This is extremely important for applications such as two-photon microscopy. MII has been demonstrated on a number of different samples ranging from atoms to crystals and from isolated molecules to proteins in solution.

Applying Multiphoton Intrapulse Interference Phase Scan

The principle of MII can be used to measure spectral phase distortions in ultrashort laser pulses. Unlike pulses from nanosecond or even picosecond laser sources, femtosecond pulses are easily dispersed (broadened in time) when propagating through any medium different than vacuum. Therefore, applications requiring femtosecond lasers depend on accurate compensation of dispersion effects. MIIPS technology integrates pulse characterization and automated compensation. MIIPS is ideal for industrial, as well as clinical, applications requiring lasers that consistently deliver identical pulses to the target, ensuring reproducibility.

Licensing

To exploit the strength of our IP portfolio, BSI is offering licensing rights in areas outside of our strategic focus. For further information on licensing terms and conditions, please contact us.

Resources

References

  1. Measurement and Repair: The Femtosecond Wheatstone Bridge
    M. Dantus et al., OE Magazine 9 (2003)
  2. Multiphoton intrapulse interference 4: Characterization and compensation of the spectral phase of ultrashort laser pulses
    V.V. Lozovoy et al., Optics Letters 29, 775 (2004)
  3. Quantitative investigation of the multiphoton intrapulse interference phase scan method for simultaneous phase measurement and compensation of femtosecond laser pulses
    B. W. Xu et al., J. Opt. Soc. Am. B-Opt. Phys. 23, 750 (2006)
  4. Interference without an interferometer: a different approach to measuring, compressing, and shaping ultrashort laser pulses
    Y. Coello et al., J. Opt. Soc. Am. B-Opt. Phys. 25, A140 (2008)
  5. Direct measurement of spectral phase for ultrashort laser pulses
    V.V. Lozovoy et al., Optics Express 16, 592 (2008)

Our products, the MIIPS® technology and its use may be covered by one or more of the following US patents 7,105,811; 7,439,497; 7,450,618; 7,567,596; 7,583,710; 7,609,731; 7,973,936; 8,208,504 and 8,208,505. European patents: EP 1,723,704 as well as other US or international patents pending.