Generation and imaging of a tunable ultrafast intensity-rotating optical field with a cycle down to femtosecond region

Abstract

A tunable ultrafast intensity-rotating optical field is generated by overlapping a pair of 20 Hz, 800 nm chirped pulses with a Michelson interferometer (MI). Its rotating rate can be up to 10 trillion radians per second ( $\text{Trad}/\text{s}$ ), which can be flexibly tuned with a mirror in the MI. Besides, its fold rotational symmetry structure is also changeable by controlling the difference from the topological charges of the pulse pair. Experimentally, we have successfully developed a two-petal lattice with a tunable rotating speed from $3.9~\text{Trad}/\text{s}$ up to $11.9~\text{Trad}/\text{s}$ , which is confirmed by our single-shot ultrafast frame imager based on noncollinear optical-parametric amplification with its highest frame rate of 15 trillion frames per second (Tfps). This work is carried out at a low repetition rate. Therefore, it can be applied at relativistic, even ultrarelativistic, intensities, which usually operate in low repetition rate ultrashort and ultraintense laser systems. We believe that it may have application in laser-plasma-based accelerators, strong terahertz radiations and celestial phenomena.

High-spatial-resolution ultrafast framing imaging at 15 trillion frames per second by optical parametric amplification

“…7(b) in the Appendix, including an asymmetric Michelson interferometer and a spiral phase generator (SPG). 35 Its low repetition rate (20 Hz) means that this kind of optical field can be boosted up to extremely high power (e.g., tens of terawatts, even higher). However, for a laser system, a low repetition rate usually comes with a large shot-shot fluctuation of its output pulses so that the pump-probe method may result in a considerable measurement inaccuracy.…”

“…The second target is an ultrafast rotating optical field. 35 As shown in Fig. 7(b), a chirped pulse, which is converted into a vortex pulse by an SPG, passes through an asymmetric Michelson interferometer where there are three mirrors (M1 to M3) in one arm, while there are two mirrors (for time delay) in the other.…”

“…(b) Setup of the ultrafast rotating optical lattice generation. 35 SPG, spiral phase generator; M1 to M4, mirrors; BS1 and BS2, beam splitters; and DL, delay line.…”

Twisted plasma waves driven by twisted ponderomotive force

“…Various new simulation phenomena and theories on interactions between intense LG mode laser beams and plasma have been proposed [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22]. In experiments, several works have been reported [23,24,16,25,26,27,28]. But high-efficiency OAM exchange between plasma and field still needs more attention.…”

Optical image rotation based on orbital angular momentum decomposition and combination

“…The optical vortex featured a spiral phase perpendicular to the direction of propagation, such as the Laguerre-Gaussian beam and Bessel beam [17,18]. Due to the existence of OAM, the phenomena are usually associated with rotation, such as optical spanner [19,20], rotating optical beams [21,22], and rotational Doppler shift [23,24].…”