Coherent X-ray Amplification (XAmp) is a method that can be used to boost the scattering signal of a weakly-scattering entity above some noisy contaminating background. The technique consists of bringing a specially-designed 'amplifier' nano-structure close to the sample of interest (within one coherence volume). The coherent interference between the sample of interest and the amplifier gives rise to an interference term in the scattering pattern seen on the detector. Even if the sample itself is too weak to be measured on its own (due to the background dominating), the interference term can be extremely strong (if the amplifier itself scatters strongly). As a result, the sample's scattering can be inferred from the measurable interference term.
The scattering from coherent interference involves three scattering terms:
- The scattering of the amplifier
- The scattering of the sample
- An interference term
This interference term encodes information about the sample, and may be amplified by increasing the amplifier signal strength (i.e. fabricating a more strongly scattering amplifier object). If a strong noisy background is present, then a sufficiently strong amplifier can actually increase the signal-to-noise of the measurement of the sample.
- Julien R. Lhermitte, Cheng Tian, Aaron Stein, Atikur Rahman, Yugang Zhang, Lutz Wiegart, Andrei Fluerasu, Oleg Gang, and Kevin G. Yager Robust X-ray angular correlations for the study of meso-structures J. Appl. Cryst. 2017, 50(3). doi: 10.1107/S1600576717003946
- Julien R. Lhermitte, Aaron Stein, Cheng Tian, Yugang Zhang, Lutz Wiegart, Andrei Fluerasu, Oleg Gang, and Kevin G. Yager Coherent Amplification of X-ray Scattering from Meso-structures IUCrJ 2017 4(5) doi: 10.1107/S2052252517008107