In situ study of two interacting femtosecond filaments in sapphire

Abstract

Interaction dynamics of two copropagating femtosecond light filaments in sapphire crystal is studied by means of time-resolved off-axis digital holographic and shadowgraphic microscopy with 22 fs temporal and 1 μm spatial resolution. In particular, we demonstrate that filament interaction originates from instantaneous modification of the refractive index resulting from the Kerr effect. Fusion, splitting, and even suppression of the resulting plasma channels induced by interacting filaments was observed by varying time delay between the input pulses. Free electron channels were reconstructed in the form of the time-lapse movie with unprecedented spatial and temporal resolution.

Supercontinuum generation by co-filamentation of two color femtosecond laser pulses

“…This could be attributed to a relatively long lifetime of free electron plasma in sapphire, see e.g. 15 , which is produced by the multiphoton absorption, inverse bremsstrahlung effect and induced avalanche ionization.…”

“…Interactions between two filament-forming beams open new perspectives for in-flight control of filament propagation, as demonstrated employing various interaction geometries in gaseous 9–12 and solid-state 13–15 media. Even more possibilities are offered by the so-called two-color filamentation, i.e.…”

Метод Лазерной Колорации В Экспериментах По Филаментации Одиночных Импульсов И Образованию Световых Пуль В Однородных Прозрачных Диэлектриках

“…Загибание" их к направлению оси по мере распространения можно объяснить влиянием зоны отрицательного (керровского) сдвига фазы, создаваемой передним импульсом [20].…”

“…При энергиях выше 20 µJ (∼ 150 P cr ) возникает режим множественной филаментации (рис. 1, f), при котором можно наблюдать появление дополнительных филаментов, направленных от переднего импульса к заднему и демонстрирующих возникновение соответствующих потоков энергии [20].…”

Flatfield Ultrafast Imaging with Single-Shot Non-Synchronous Array Photography

“…Often, ultrafast dynamics are measured by repeated acquisitions. [4][5][6][7]. However, this approach is not feasible for events that are difficult or impossible to reproduce, such as optical rogue waves [8], irreversible phase transitions [9], or laser-plasma interactions [10], thus motivating the development of techniques that are single shot.…”