Iterative Frequency-Domain Interferometry Technology for Ultrafast Phase Measurement
- PDF / 414,418 Bytes
- 5 Pages / 594 x 792 pts Page_size
- 44 Downloads / 209 Views
Journal of Applied Spectroscopy, Vol. 87, No. 4, September, 2020 (Russian Original Vol. 87, No. 4, July–August, 2020)
ITERATIVE FREQUENCY-DOMAIN INTERFEROMETRY TECHNOLOGY FOR ULTRAFAST PHASE MEASUREMENT Y. Fan,a,b* J. Xiao,b and Y. Lia
UDC 535.317.1
This paper presents an original design of the single-shot iterative frequency-domain interferometry (IFDI) technology to measure the ultrafast phase. Unlike frequency domain holography (FDH), in which the reference pulse interferes with the phase-modulated probe pulse, in IFDI two linearly chirped probe pulses co-propagate and are both phasemodulated by the measured ultrafast phase, and then the phase can be reconstructed with the iterative algorithm. Compared with two types of FDH, the IFDI technology has better accuracy and stability. Keywords: iterative frequency-domain interferometry, single-shot measurement, time-resolved imaging. Introduction. Direct observation of the dynamic interplay among drive pulse, plasma wave, and accelerated electrons, including wave-breaking, pump depletion, and beam loading, is essential for realizing potential applications of plasma accelerators in many fields such as radiobiology, radiotherapy, radiographic materials inspection, ultrafast chemistry, and high-energy physics. As a single-shot interferometric technique, frequency domain holography (FDH) can measure the ultrafast phase caused by laser-generated nonlinear refractive index structures. FDH opens a direct window into microscopic physics and is an essential step towards controlling the above-mentioned dynamics. Using FDH, Le Blanc et al. realized a single-shot time-resolved measurement of the ultrafast phase shifts induced either by the nonlinear susceptibility χ3 of fused silica or by ionization fronts in air over a temporal region of 1 ps with a 70 fs resolution [1]. Then, using FDH, Matlis et al. demonstrated a single-shot visualization of laser-wake field accelerator structures for the first time [2]. Li et al.'s experimental results illustrate both the strengths (fast, faithful single-shot imaging of most aspects of the wake structure) and limitations (underestimate of plasma oscillation amplitude when the plasma structure evolves significantly, false structure from pump-generated radiation) of FDH imaging [3]. Furthermore, Li et al. presented a generalization of FDH known as frequency domain tomography (FDT), which incorporates several FDHs having different angles between probe pulse and drive pulse, to visualize evolving light-velocity objects [4]. However, there are some application limits of FDH. In this paper, FDH was divided to two types, and the limits of FDH were analyzed. Here, a new design of the iterative frequency-domain interferometry (IFDI) technology was proposed, and a comparison between FDH and IFDI confirmed the feasibility and accuracy of IFDI technology. FDH Limitation Analysis and IFDI Technology. In FDH, a wide-bandwidth, temporally extended probe pulse co-propagates with the drive pulse through the medium, illuminating the entire object being mea
Data Loading...
