Two-step phase-shifting SPIDER

Abstract

Comprehensive characterization of ultrafast optical field is critical for ultrashort pulse generation and its application. This paper combines two-step phase-shifting (TSPS) into the spectral phase interferometry for direct electric-field reconstruction (SPIDER) to improve the reconstruction of ultrafast optical-fields. This novel SPIDER can remove experimentally the dc portion occurring in traditional SPIDER method by recording two spectral interferograms with π phase-shifting. As a result, the reconstructed results are much less disturbed by the time delay between the test pulse replicas and the temporal widths of the filter window, thus more reliable. What is more, this SPIDER can work efficiently even the time delay is so small or the measured bandwidth is so narrow that strong overlap happens between the dc and ac portions, which allows it to be able to characterize the test pulses with complicated temporal/spectral structures or narrow bandwidths.

Accurate reconstruction of electric field of ultrashort laser pulse with complete two-step phase-shifting

“…We have first applied the TSPS method to SPIDER in Ref. [12] (T-SPIDER), where a quarter-wave plate (equivalent to a half-wave plate when the light passes twice) is set in one of the MI arms to induce phase-shifting by aligning the polarization respectively along the fast axis or the slow axis of the wave plate at twice. When aligning the polarization along the fast axis, we record an interferogram as expressed by Equation (1), and then by rotating the wave plate by , we can record another interferogram with phase-shifting expressed by where expresses a small phase deviation from due to the dispersion of the wave plate.…”

“…As shown in Figure 1(b), the CG, includes a couple of oppositely placed prisms made of SF57 glass (RP1 and RP2), two prism corner reflectors (CR1 and CR2) and a prism beam splitter (BS2). RP1 and RP2 act as a compact pulse stretcher [12, 14] , which folds the light path inside the prisms to induce adjustable material dispersion to chirp the input pulse. According to our measurement, this prism pair can stretch the 35 fs pulse at 800 nm to a range from 2.5 ps to 12.5 ps easily by changing the malposed distance between the prism pair.…”

“…Previously, we have successfully combined two-step phase-shifting (TSPS) into SPIDER [12] , called T-SPIDER here, where two spectral interferograms with phase-shifting are recorded to remove experimentally the effect of the dc portion occurring in traditional SPIDER method. T-SPIDER can effectively avoid the disturbances from the time delay ( ) between the test pulse replicas and the temporal filtering in the traditional SPIDER method.…”

The Development of the Temporal Measurements for Ultrashort Laser Pulses

“…Moreover, the recorded 2D data means a longer time required to process than the usual 1D data. Recently, we have successfully combined two-step phase-shifting (TSPS) into SPIDER [65], which can expend the filtering window to the positive (or negative) semi-axis in the Fourier domain by using 1D measurement. A quarter waveplate is inserted into one arm of the MI pulse replicator to control the zero-order additional phase at θ 0 or θ 0 + π, respectively, to generate two spectral interferograms with π phase-shifting.…”

Improved common-path spectral interferometer for single-shot terahertz detection

“…The beam used as probe is about 20 mW. A beam sampler is used to reflect a small part of the probe (∼1 mW) for characterizing the temporal/spectral phase of the probe in real time by our homemade spectral phase interferometer for direct electrical field reconstruction (SPIDER) [21]. The transmission of the sampler then passes through a stretcher, including a pair of 180°folding right-angle SF57 prisms, to be stretched up to 12 ps, which is long enough to temporally cover the target THz field.…”