Refractive index Petr Šafařík

Petr Šafařík Masaryk university: Astrophysics Institute of Scientific Instruments: Coherence Optics E-mail:petos@mail.muni.cz E-mail: petos@isibrno.cz ICQ: 137-455-645 Jabber:petos@physics.muni.cz http://physics.muni.cz/~petos

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

Theory Definition of refractive index: Usually given the symbol The refractive index of a medium is defined as ratio of the phase velocity in the reference medium to velocity in the medium itself. Reference medium: usualy vacuum. Usually given the symbol

Theory In case of light:

Phase & group velocity The phase velocity of a wave is the rate at which the phase of the wave propagates in space. This is the velocity at which the phase of any one frequency component of the wave will propagate. You could pick one particular phase of the wave (for example the crest) and it would appear to travel at the phase velocity. The phase velocity is given in terms of the wave's angular frequency ω and wave vector k by: V_p = omega / k The group velocity of a wave is the velocity with which the variations in the shape of the wave's amplitude propagate through space. V_g = partial derivation omega by k

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

Methods of measuring Indirect – Edlén‘s formula Direct – Laser refratometer

Methods of measuring Indirect – Edlén‘s formula Direct – Laser refratometer

Indirect – Edlén‘s formula p – pressure t – temperature (s-1) – dispersion coefficient

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Methods of measuring Indirect – Edlén‘s formula Direct – Laser refratometer

Methods of measuring Indirect – Edlén‘s formula Direct – Laser refratometer

Laser refractometer Michelson‘s interferometr:

Laser refractometer Refractometr based on Michelson: D - detector, L – laser, M – Mirror VP - Vacuum pump, VM - Vacuum meter , VS- Vacuum sensor

Laser refractometer Examples of interference fringes:

Fabry-Perot based refractometer Scheme:

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

My results Scheme:

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

Summary Light rays chanfe direction, when they cross the interface from material to other one by the Snellius law: Light reflects partially from surfaces, that have refractive index fifferent from that of their suroundings.

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

Outline Theory of the refractive index Methods of measuring refractive index My results at ISI Brno Summary Questions

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