A self-induced white light seeding laser in a femtosecond laser filament

Abstract

Abstract:We report, for what we believe to be the first time, on the generation of remote self-seeding laser amplification by using only one 800 nm Ti:Sapphire femtosecond laser pulse. The laser pulse (∼40 fs) is first used to generate a filament either in pure nitrogen or in ambient air in which population inversion between the

Femtosecond laser ionization and fragmentation of molecules for environmental sensing

“…As introduced in the above section, by using only one infrared pump laser light at ∼1.9 μm, remote forward laser actions can be realized , but the limited output energy of the infrared laser pulse from the optical parametric amplifier (OPA) makes it hard to generate a filament at a far distance. It is therefore expected that the generation of remotely coherent lasers could be realized directly by using commercially available high‐power Ti:sapphire laser systems with the wavelength at 800 nm .…”

“…By using the white‐light (supercontinuum) generated during the filamentation in air as the seed, the remote self‐seeding laser amplification by using only one 800‐nm Ti:sapphire femtosecond laser pulse was achieved almost at the same time by several groups . The self‐induced narrowband laser at 428 nm has a pulse duration of ∼2–3 ps with perfect linear polarization property, but the lasing emission shows a doughnut pattern, as shown in Fig.…”

“…Due to a variety of nonlinear effects of atoms/molecules induced by such strong fields in a filament , the subject of femtosecond laser filamentation has been a hot research topic, associating with a lot of potentially challenging physics and applications such as THz radiation generation , lightning and weather control , remote air lasing , few‐cycle pulse generation , and high‐harmonic generation . In particular, the laser intensity inside a filament is high enough to induce remote ionization and fragmentation of molecules , giving rise to characteristic fingerprint fluorescence emissions from the ionized molecules or fragments that could be used for identifying the parent molecules.…”

Nonlinear rovibrational polarization response of water vapor to ultrashort long-wave infrared pulses

“…This phenomenon has possible applications in longrange free-space optical communication, remote sensing [4,5], synthesis of ultrashort pulses by higher harmonics generation [6,7], and lightning guiding [8][9][10], to name but a few. The atmospheric transparency windows in the mid-wave infrared (MWIR) (3-5 μm) [11,12] and long-wave infrared (LWIR) (8-12 μm) [13,14] regimes are of particular interest.…”

Effect of Spatial Modulation on Pulse Width for Ultrashort Laser Pulse during Small-Scale Self-Focusing

“…This situation is easily leading to generating SSSF in nonlinear case [4]. SSSF leaded to off-axis energy moving toward the peak of the pulse and the laser pulse compressed in both space and time, which caused the peak intensity augmenting [5,6]. The increase of peak intensity caused self-phase modulation (SPM) to enhance, which leaded to generating new frequency components [7,8].…”