Phase-matched four-wave mixing of sub-100-TW/ cm2 femtosecond laser pulses in isolated air-guided modes of a hollow photonic-crystal fiber.
Hollow-core photonic-crystal fibers are shown to allow propagation and nonlinear-optical frequency conversion of high-intensity ultrashort laser pulses in the regime of isolated guided modes confined in the hollow gas-filled fiber core. With a specially designed dispersion of such modes, the 3omega=2omega+2omega-omega four-wave mixing of fundamental (omega) and second-harmonic (2omega) sub-100- TW/ cm(2) femtosecond pulses of a Cr:forsterite laser can be phase matched in a hollow photonic-crystal fiber within a spectral band of more than 10 nm, resulting in the efficient generation of femtosecond pulses in a well-resolved higher-order air-guided mode of 417-nm radiation.
Konorov
S O
SO
Physics Department, International Laser Center, M. V. Lomonosov Moscow State University, 119899 Moscow, Russia.
Serebryannikov
E E
EE
Akimov
D A
DA
Ivanov
A A
AA
Alfimov
M V
MV
Zheltikov
A M
AM