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Ultrafast and versatile spectroscopy by temporal Fourier transform.

Zhang C, Wei X, Marhic ME, Wong KK - Sci Rep (2014)

Bottom Line: One of the most remarkable and useful properties of a spatially converging lens system is its inherent ability to perform the Fourier transform; the same applies for the time-lens system.On the other hand, in addition to the single-lens structure, the multi-lens structures (e.g. telescope or wide-angle scope) will provide very versatile operating conditions.Leveraging the merit of instantaneous response, as well as the flexible lens structure, here we present a 100-MHz frame rate spectroscopy system - the parametric spectro-temporal analyzer (PASTA), which achieves 17 times zoom in/out ratio for different observation ranges.

View Article: PubMed Central - PubMed

Affiliation: Photonic Systems Research Laboratory, Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong.

ABSTRACT
One of the most remarkable and useful properties of a spatially converging lens system is its inherent ability to perform the Fourier transform; the same applies for the time-lens system. At the back focal plane of the time-lens, the spectral information can be instantaneously obtained in the time axis. By implementing temporal Fourier transform for spectroscopy applications, this time-lens-based architecture can provide orders of magnitude improvement over the state-of-art spatial-dispersion-based spectroscopy in terms of the frame rate. On the other hand, in addition to the single-lens structure, the multi-lens structures (e.g. telescope or wide-angle scope) will provide very versatile operating conditions. Leveraging the merit of instantaneous response, as well as the flexible lens structure, here we present a 100-MHz frame rate spectroscopy system - the parametric spectro-temporal analyzer (PASTA), which achieves 17 times zoom in/out ratio for different observation ranges.

No MeSH data available.


Related in: MedlinePlus

Design and implementation of the telescope/wide-angle PASTA.(a), Detailed experimental setup. Two time-lenses are achieved by a FWM-based parametric mixer, and the two swept pumps are derived from the same pulsed source, passing through different dispersive fibers. (b) & (c), The signal wavelength-to-time ratio changes step by step through the telescope/wide-angle PASTA process.
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f2: Design and implementation of the telescope/wide-angle PASTA.(a), Detailed experimental setup. Two time-lenses are achieved by a FWM-based parametric mixer, and the two swept pumps are derived from the same pulsed source, passing through different dispersive fibers. (b) & (c), The signal wavelength-to-time ratio changes step by step through the telescope/wide-angle PASTA process.

Mentions: There are two time-lenses involved in the telescope/wide-angle PASTA, and they are implemented by two stages of four-wave mixing (FWM). A pulsed source (2-ps pulsewidth) passing through different pump dispersions provides the swept pumps for two FWMs2223. It is noted that every stage of FWM also acts as a spectral mirror (or phase conjugator)24; therefore, it is required to have an even number of stages to compensate this effect. This explains why in the single-lens PASTA configuration, the single time-lens was also implemented by two stages of FWM: the second-stage FWM pumped by a CW source (Φp2 = +∞ ps2) only acted as a spectral mirror10. Since there is no dispersion between these two FWMs, the mid-span dispersion Φm = 0 ps2, as shown in Fig. 2(a) and Table 1. In the case of the telescope/wide-angle PASTA, as in the space-lens, the distance between the two lenses is critical to control the divergence of the light beam; the mid-span dispersion (Φm) between the two time-lenses is important to adjust the wavelength-to-time ratio.


Ultrafast and versatile spectroscopy by temporal Fourier transform.

Zhang C, Wei X, Marhic ME, Wong KK - Sci Rep (2014)

Design and implementation of the telescope/wide-angle PASTA.(a), Detailed experimental setup. Two time-lenses are achieved by a FWM-based parametric mixer, and the two swept pumps are derived from the same pulsed source, passing through different dispersive fibers. (b) & (c), The signal wavelength-to-time ratio changes step by step through the telescope/wide-angle PASTA process.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061551&req=5

f2: Design and implementation of the telescope/wide-angle PASTA.(a), Detailed experimental setup. Two time-lenses are achieved by a FWM-based parametric mixer, and the two swept pumps are derived from the same pulsed source, passing through different dispersive fibers. (b) & (c), The signal wavelength-to-time ratio changes step by step through the telescope/wide-angle PASTA process.
Mentions: There are two time-lenses involved in the telescope/wide-angle PASTA, and they are implemented by two stages of four-wave mixing (FWM). A pulsed source (2-ps pulsewidth) passing through different pump dispersions provides the swept pumps for two FWMs2223. It is noted that every stage of FWM also acts as a spectral mirror (or phase conjugator)24; therefore, it is required to have an even number of stages to compensate this effect. This explains why in the single-lens PASTA configuration, the single time-lens was also implemented by two stages of FWM: the second-stage FWM pumped by a CW source (Φp2 = +∞ ps2) only acted as a spectral mirror10. Since there is no dispersion between these two FWMs, the mid-span dispersion Φm = 0 ps2, as shown in Fig. 2(a) and Table 1. In the case of the telescope/wide-angle PASTA, as in the space-lens, the distance between the two lenses is critical to control the divergence of the light beam; the mid-span dispersion (Φm) between the two time-lenses is important to adjust the wavelength-to-time ratio.

Bottom Line: One of the most remarkable and useful properties of a spatially converging lens system is its inherent ability to perform the Fourier transform; the same applies for the time-lens system.On the other hand, in addition to the single-lens structure, the multi-lens structures (e.g. telescope or wide-angle scope) will provide very versatile operating conditions.Leveraging the merit of instantaneous response, as well as the flexible lens structure, here we present a 100-MHz frame rate spectroscopy system - the parametric spectro-temporal analyzer (PASTA), which achieves 17 times zoom in/out ratio for different observation ranges.

View Article: PubMed Central - PubMed

Affiliation: Photonic Systems Research Laboratory, Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong.

ABSTRACT
One of the most remarkable and useful properties of a spatially converging lens system is its inherent ability to perform the Fourier transform; the same applies for the time-lens system. At the back focal plane of the time-lens, the spectral information can be instantaneously obtained in the time axis. By implementing temporal Fourier transform for spectroscopy applications, this time-lens-based architecture can provide orders of magnitude improvement over the state-of-art spatial-dispersion-based spectroscopy in terms of the frame rate. On the other hand, in addition to the single-lens structure, the multi-lens structures (e.g. telescope or wide-angle scope) will provide very versatile operating conditions. Leveraging the merit of instantaneous response, as well as the flexible lens structure, here we present a 100-MHz frame rate spectroscopy system - the parametric spectro-temporal analyzer (PASTA), which achieves 17 times zoom in/out ratio for different observation ranges.

No MeSH data available.


Related in: MedlinePlus