1 / 15

Understanding Laser Characteristics and Broadening Effects in Spectroscopy

This document explores key characteristics of lasers, particularly those related to Nd:YAG lasers, including directionality, monochromaticity, brightness, and coherence. We discuss the concepts of threshold, linewidths, and both homogeneous and inhomogeneous broadening. The effects of the time-energy uncertainty principle on linewidth and pressure broadening are addressed. By using various statistical methods, we analyze distributions of molecular transition energies, emphasizing Gaussian functions and Doppler broadening. Additionally, essential terms such as FWHM and Lorentzian lineshapes are introduced to enhance understanding of the subject.

twyla
Télécharger la présentation

Understanding Laser Characteristics and Broadening Effects in Spectroscopy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. From Reinhard Schinke

  2. From Reinhard Schinke

  3. From Reinhard Schinke

  4. From Reinhard Schinke

  5. From Reinhard Schinke

  6. Lasers: N2>>N1 2 A23 B21W(w) A21 B23Wp(w) 1 A13 3

  7. Lasers: N2>>N1 2 Lase A23 B21W(w) A21 slow B23Wp(w) 1 Pump A13 fast 3

  8. Nd3+:Y3Al5O12 (YAG)

  9. Cavity—2 mirrors separated by nl/2 Lasers characterized by: Directionality Monochromatic Brightness Coherence Discuss: Threshhold

  10. Linewidths Homogeneous Broadening: Affects every molecule the same way e.g. time energy uncertainty principle and pressure broadening dEdt h dndt 1 sets a minimum linewidth of dw  t-1 Expressed as e-t/tdecay of final state probability the corresponds after Fourier transform to a Lorentzian lineshape FWHM=t

  11. Linewidths Inhomogeneous broadening: Collection of molecules have a distribution of transition energies. Typically given by statistics of different molecular environments and described by Gaussian functions. FWHM=2s(2ln2) e.g. Doppler Broadening

  12. Mon Feb 18 Presidents day • Weds: Rayleigh and Raman Scattering • Weds Feb 27: Projects Part1

More Related