Materials Characterization Techniques

Materials Characterization Techniques I: Microscopy & diffraction Jin Won (Maria) Seo March-May 2020

1. Introduction • How to decide which technique to apply?

Microscopy: resolution penetration depth Spectroscopy: nowadays combination of physical interaction techniques => e.g. correlative microscopy secondary effects Diffraction: ordering + disordering nature of interaction, diffraction configuration

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Materials Characterization Techniques 1

Faculty of Engineering, department MTM

1. Introduction • Overview techniques: dimension vs. resolution

I.D. Campbell, The Croonian Lecture 2006 11

Materials Characterization Techniques 1

Faculty of Engineering, department MTM

1. Introduction • Overview techniques: analysis profile depth

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Materials Characterization Techniques 1

Faculty of Engineering, department MTM

2. Microscopy • Resolution It is a matter of wavelength‌. and lenses

http://nobelprize.org/educational_games/physics/microscopes/powerline/index.html 15

Materials Characterization Techniques 1

Faculty of Engineering, department MTM

2.1 Optical Microscopy • Optical lens: refraction change in direction of the light caused by the change in its speed the resulting refraction angle b

n1 sin � = n2 sin �

Objective lens Condenser lens Intermediate lens Eyepiece

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Materials Characterization Techniques 1

Faculty of Engineering, department MTM

2.1 Optical Microscopy • Optical lens: aberration

Objectives: achromats: - fully corrected for chromatic aberration at two wavelengths (blue and red) - for spherical aberration at an intermediate wavelength (green light). plan apochromats: - fully corrected for the full visible range (red, green and blue light) - in-focus image over the full field of view.

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Materials Characterization Techniques 1

Faculty of Engineering, department MTM

2.1 Optical Microscopy • Optical lens: human eye l l l l

sensitive to 400 – 700 nm peak sensitivity around 560 nm spatial resolution around 0.2 mm temporal resolution around 15-20/ sec

- lens focuses an image onto the retina - iris acts as a variable aperture - immersion lens system: space between the lens and the retina filled with liquid - curvature of the lens in the eye can be adjusted by a system of muscles 21

Materials Characterization Techniques 1

Faculty of Engineering, department MTM

2.1 Optical Microscopy • Angular resolution:

đ?‘ đ??´ = đ?œ‡ sin đ?›ź

Nikon Microscopy Education http://www.microscopyu.com/tutorials/java/imageformation/airyna/index.html 25

Materials Characterization Techniques 1

Faculty of Engineering, department MTM

2.1 Optical Microscopy • Angular resolution Rayleigh resolution criterion:

đ?›ż = 0.61 đ?œ†/đ?œ‡ sin đ?›ź

the resolving power of any image-forming device based on a lens, e.g. telescope, microscope, camera, eye.... but assumes perfect aberration-free lenses effect of aberration: Hubble-telescope

digital resolution: Don’

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Materials Characterization Techniques 1

Faculty of Engineering, department MTM

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