Spectrally narrow features in a supercontinuum generated by shaped pulse trains

Area of Science:

• Nonlinear optics
• Laser physics
• Materials science

Background:

• Supercontinuum generation in photonic crystal fibers (PCFs) produces broadband light using femtosecond laser pulses.
• Higher power density at specific wavelengths is often desired for specialized applications.
• Increasing pump power broadens the spectrum but does not enhance specific wavelength densities.

Purpose of the Study:

• To demonstrate a method for enhancing spectral energy density at specific wavelengths within a supercontinuum.
• To achieve tunable enhancement of specific wavelengths in PCF supercontinuum generation.

Main Methods:

• Utilizing femtosecond laser pulses as input.
• Employing a pulse shaper to apply periodic spectral phase modulation.
• Generating supercontinuum light via photonic crystal fibers.

Main Results:

• Achieved nearly an order of magnitude enhancement in spectral energy density at selected wavelengths.
• Demonstrated tunability of the enhanced wavelengths.
• Showed that spectral phase modulation is effective for targeted spectral energy enhancement.

Conclusions:

• Periodic spectral phase modulation is a viable technique to control and enhance specific wavelengths in PCF supercontinuum generation.
• This method offers a way to tailor supercontinuum spectra for applications requiring high power density at particular wavelengths.