Opinion
and the imaging lenses, finding the sample, re-focusing, and correcting beam tilt; and (b) the change of object magnifi- cation also changes the magnification of the interference, requiring the adjustment of the voltage at the biprism and at least one of the imaging lenses. Both (a) and (b) have to be balanced iteratively, adding to the long delays when chang- ing magnification. Thus changing from an overview of the specimen area to a more detailed view rudely interrupts live phase imaging—and that is where most users lose interest in the technique. Te solution. Te solution is to separate the magnification
of the interference fringes (with respect to the camera) from the magnification of the object. An approach to this was proposed in 2001 [13]. As shown in Figure 1, adding lenses between the objective lens and the biprism allows magnification changes of the sample while the original lenses below the biprism main- tain the interference fringes with respect to the camera. Add- ing lenses to the optical train in the suggested area should not be complicated; Cs correctors are more complex, and we know how to handle them. I believe it is time for this simple modification to be
made in a well-designed holography microscope. Such a microscope could be used like any other transmission elec- tron microscope, but it would allow imaging the object simultaneously in its intensity and phase, live in real time. Then magnetic and electric fields become visible supporting investigations of p-n junctions, magnetoresistive RAM, and electric fields around toner particles. At high resolution, local crystal tilt becomes obvious on the unit-cell scale, and biological objects would show much improved contrast even under low dose conditions—to name a few applications. Thus, electron holography could truly evolve into a main- stream technology and provide in real time all the informa- tion the electron wave contains.
References [1] “Frits Zernike,” Wikipedia, Te accessed June 3, 2018.
Free Encyclopedia,
[2] D Gabor, Nature 161(4098) (1948) 777–78. [3] G Möllenstedt and H Düker, Naturwissenschaſten 42 (1955) 41.
[4] EN Leith and J Upatnieks, J Opt Soc Am 52(10) (1962) 1123–30.
[5] O Scherzer, J Appl Phys 20 (1949) 20. [6] HW Zandbergen and DV Dyck, Microsc Res Techniq 49(3) (2000) 301–23.
[7] H Rose, Optik 39 (1973–74) 416. [8] E Voelkl et al., Scanning Microscopy 11 (1997) 407–16. [9] D Cooper et al., Appl Phys Lett 91 (2007) 143501.
[10] E Voelkl and D Tang, Ultramicroscopy 110 (2010) 447–59.
[11] E Voelkl and A Ponce Microsc Microanal 24 (Suppl 1) (2018) 1462–63.
[12] E Voelkl et al., Microsc Microanal 21 (Suppl 3) (2015) 1951–52.
[13] E Voelkl et al., Electron holography microscope. US Pat- ent 6,617,580, filed December 27, 2001.
2019 January •
www.microscopy-today.com
Comparison of duoplasmatron versus Hyperion (operating on Cameca NanoSIMS) shows beam current as a function of spot size.
Upgrade Your Ions
Hyperion™ Dual Polarity Ion Sources are now available as direct upgrades from Oregon Physics for FEI FIB 200, PHI Adept 1010, and Cameca NanoSIMS, IMS F series, and 12XX series instruments.
Upgrade your ion source to benefit from: • Longer source lifetime • Better image resolution • Improved depth profiling (SIMS) • Higher currents for milling (FIB)
Oregon Physics’ Hyperion ion sources are designed to bolt-on to your existing optical system for easy implementation.
How will Hyperion improve your research? Learn more at
Oregon-Physics.com or call us to discuss your requirements.
+1 503 601 0041
info@oregon-physics.com
www.oregon-physics.com
35
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52
