Semitransparency in interaction-free measurements

Thomas, Sebastian; Kohstall, Christoph; Kruit, P.; Hommelhoff, Peter

doi:10.1103/physreva.90.053840

Cited by 62 publications

(30 citation statements)

References 28 publications

(62 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These MSEs were calcluated using Monte-Carlo simulations. The MSE for 7 < is very close to the Cramér-Rao bound, and much lower than the MSE for 8 <. However, MSE for 8 < is approximately constant for all .…”

supporting

confidence: 52%

“…Recently, with the implementation of Mach-Zehnder interferometers in conventional transmission electron microscopes (TEMs), it has become possible to potentially implement IFM in these tools [4][5][6]. Therefore, a comparison of the theoretical performance of IFM with conventional microscopy is of interest [7].In this work, we theoretically analyzed the performance of IFM imaging of both opaque-and-transparent and semitransparent samples, and compared it to the performance of conventional scanning transmission electron microscopy (STEM) [8]. For opaque-and-transparent samples, we compared the performances of the two schemes using two metrics -"## , the probability of misidentifying an opaque pixel as transparent or vice-versa, and %&'&(" , the mean number of electrons required to image an opaque pixel.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…Future work will focus on combining this analysis with conditional re-illumination, to obtain the best possible performance for IFM imaging of semi-transparent samples [9]. 7 <, while the dashed-dotted ornage curve is the MSE for estimator 8 <. These MSEs were calcluated using Monte-Carlo simulations.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Performance Analysis of Interaction-Free-Measurement-based Electron Microscopy

2019

View full text Add to dashboard Cite

Interaction-free measurement (IFM) has been proposed as a method of reduced-damage electron microscopy [1][2][3]. Recently, with the implementation of Mach-Zehnder interferometers in conventional transmission electron microscopes (TEMs), it has become possible to potentially implement IFM in these tools [4][5][6]. Therefore, a comparison of the theoretical performance of IFM with conventional microscopy is of interest [7].In this work, we theoretically analyzed the performance of IFM imaging of both opaque-and-transparent and semitransparent samples, and compared it to the performance of conventional scanning transmission electron microscopy (STEM) [8]. For opaque-and-transparent samples, we compared the performances of the two schemes using two metrics -"## , the probability of misidentifying an opaque pixel as transparent or vice-versa, and %&'&(" , the mean number of electrons required to image an opaque pixel. Figure 1(a) compares "## for IFM with that for conventional STEM, at a constant %&'&(" of 2.5 electrons per pixel, for (the prior probability of a given pixel being opaque) between 0 and 1. We performed this comparison for IFM and conventional STEM both with and without a detector for scattered electrons ( , ), to account for different microscope configurations. We can see that "## was lower for IFM (green dashed-dotted curve) than conventional STEM (purple solid curve) for a wide range of . This includes the important limit of low , which is commonly encountered for high-transparency electron microscopy samples.In figure 1(b), we compare "## vs %&'&(" for IFM and STEM, for = 0.5. In these calculations, we included a sample re-illumination scheme based on updating a prior for each pixel of the sample after each round of illumination with a Poisson-limited electron beam, based on the statistics at the imaging detectors. The re-illumination for a pixel ceases once a stopping criterion is met. This scheme reduces %&'&(" for both IFM and STEM imaging to their ideal values -⅔ for IFM imaging with , (green solid curve with square markers) and 1 for STEM imaging with , (purple solid curve with circle markers). Therefore, conditional re-illumination allowed us to circumvent the Poisson statistics of the beam.For semi-transparent samples, we treated the transparency ∈ [0,1] as a continuous random variable. The statistics at the imaging detectors can be used to form an estimate of , and the performance of the estimator can be analyzed by looking at its mean squared error (MSE). For unbiased estimators, the inverse of the classical Fisher Information (FI) forms a lower bound for this MSE (Cramér-Rao bound). We found that the FI for IFM and STEM imaging was identical, shown by the solid blue curve in figure 2. Figure 2 also shows the MSE for two estimators for -7 and 8 , calculated using Monte-Carlo simulations. These estimators use the counts from the imaging detectors in different ways -7 (purple dashed curve) averages over these counts to estimate , while 8 (orange dashed-dotted curve) uses the square of the dif...

show abstract

supporting

confidence: 52%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Performance Analysis of Interaction-Free-Measurement-based Electron Microscopy

2019

View full text Add to dashboard Cite

show abstract

“…One potential application of such a guided matter-wave system could be the nondestructive imaging of biological samples with a quantum electron microscope, as recently proposed [26,46]. Here, quantum effects in the motion of electrons that are confined by a microstructured, transverse guiding potential can be exploited to consecutively probe a sample without damage.…”

Section: Discussionmentioning

confidence: 99%

Phase-Resolved Electron Guiding in Optimized Chip-Based Microwave Potentials

et al. 2014

Self Cite

View full text Add to dashboard Cite

Surface-electrode chips are a versatile and well-established tool for trapping and guiding charged particles. The technique, usually applied to ions, has recently been adapted for electrons using a twodimensional quadrupole guide at microwave driving frequencies. During injection into the guiding potential, the electron trajectories show a strong dependence on the phase and amplitude of fringing electric fields at the coupling entrance of the guide. Here we study the corresponding electron dynamics using a pulsed electron source with pulse durations of several 100 ps to temporally resolve fringing electric fields oscillating at the microwave drive frequency. By synchronizing the timing of the electron pulses to a certain microwave phase, we can increase the electron guiding efficiency by 50%. Furthermore, we present numerically optimized electrode structures for which the amplitude of fringing electric fields at the coupling entrance of the guide is drastically reduced. Particle-tracing simulations suggest that the optimized electrode layout allows the direct injection of electrons into the lowest-lying motional quantum states of the transverse guiding potential.

show abstract

The concept of quantum electron microscopy

Kruit

Berggren

Hommelhoff³

et al. 2016

European Microscopy Congress 2016: Proceedings

View full text Add to dashboard Cite

Following a recent suggestion [1] that interaction‐free measurements are possible with electrons, we have analyzed the possibilities to use this concept for imaging of biological specimen with reduced damage. We have also made preliminary designs for an atomic resolution interaction‐free electron microscope, or “quantum electron microscope” [2], for one example see figure 1. The idea of interaction‐free measurements follows Elitzur and Vaidman [3], who proposed that an opaque object may be observed by detecting a photon that did not interact with that object. This concept uses a Mach‐Zehnder interferometer in which one branch of the particle wave passes through the specimen (“specimen beam”) while the other part follows another path (“reference beam”). For a substantial reduction of the interaction, the amplitude of the wave passing through the specimen must be small and the interaction must be repeated many times. To implement this concept in an electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam‐splitter or two‐state‐coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times. A two‐state‐coupler has the function of moving the electron wave slowly between the reference beam and the specimen beam, as in a Rabi‐oscillation. We have come up with four different choices for this: a thin crystal, a grating mirror, a standing light wave and an electro‐dynamical pseudopotential. Figures 2 shows a typical example of the theoretical output of a measurement, where for each pixel there is signal in the reference beam, the specimen beam and the inelastic channel, possibly detected in an energy loss measurement. Figure 3 shows the advantage of interaction free measurement in the detection of the presence of a dark pixel as compared to dark field microscopy. In the analysis of the image contrast that interaction‐free microscopy can create, our tentative conclusion is that transparent specimen can be detected, but different transparencies cannot be distinguished [4]. Other modes of operation of a microscope with multiple interactions with the specimen, however, may enable this.

show abstract

Semitransparency in interaction-free measurements

Cited by 62 publications

References 28 publications

Performance Analysis of Interaction-Free-Measurement-based Electron Microscopy

Performance Analysis of Interaction-Free-Measurement-based Electron Microscopy

Phase-Resolved Electron Guiding in Optimized Chip-Based Microwave Potentials

The concept of quantum electron microscopy

Contact Info

Product

Resources

About