Laser Spectroscopy Podcast: Recent Episodes
Peter Beyersdorf
Lecture recordings from Physics 268 at San Jose State University. 75 minute enhanced audio epsiodes will be added on Monday and Wednesday nights throughout Fall of 2009.
We look at sources of laser frequency noise and discuss feedback techniques using a reference cavity or a molecular transition to stabilize the laser frequency.
We look at pump probe methods using ultrafast pulses for high temporal resolution experiments.
We look at transient effects in laser gain material, -switching and mode locking as methods to get short pulses.
Podcsat from 2008 of lecture on Raman spectroscopy. This is in place of the 11/9 lecture given about Raman spectroscopy, for which the audio didn't record properly.
Podcsat from 2008 of lecture on stimulated Raman scattering. This content was not covered in class this semester. This is for your interest only and will not be covered on exams.
We look at how saturation causes hole burning in a spectral line, and measurement techniques such as lamb-dip spectroscopy and intermodulated fluorescence that can take advantage of this for doppler-free measurements.
We look at basic methods of emission spectroscopy including laser induced fluorescence, resonant enhanced multi-photon emission (REMPI), intermodulated fluorescence and stimulated emission pumping.
WE look at basic techniques of absorption spectroscopy including direct detection, frequency modulation, intracavity absorption and cavity ringdown spectroscopy.
We look at how the natural lifetime of an energy level produces a Lorentzian line profile and how the natural linewidth can be broadened by Doppler broadening, pressure broadening, transit time broadening and saturation broadening.
We look at the principles of operation of prism spectrometers and grating spectrometers and discuss operating characteristics (speed, resolving power, spectral transmission and free spectral range).
We consider the advantages and disadvantages of three classes of photodetectors: photodiodes, photomultiplier tubes and thermal detectors.
We look at several examples of tunable lasers and discuss nonlinear optics as a mechanism to increase the region of the spectrum available from laser sources.
We look at 3-level and 4-level gain systems in laser amplifiers, discuss optical cavities and tuning elements of laser oscillators.
We look at an example of calculating the bond length and bond strength of HCl from a measured mid IR absorption spectrum.
We look at the Bohr model of the atom and see how it can be used to explain the line spectrum of Hydrogen, and then generalize to other atoms.
We look at an application of our previous quantum treatment of the two-level atom for measuring G the universal gravitational constant.
We look at absorption as a quantum effect and introduce the Einstein A and B coefficients for stimulated and spontaneous emission.
We use the classical electron oscillator model to derive the functional form of the index of refraction in material as well as the absorption, which we relate to the cross section.
We investigate absorption of light by matter using the classical electron oscillator model. In the process we introduce phasor notation.
We look at spectroscopic methods to manipulate matter for use in matter wave interferometry
Laser Detection and Ranging (LIDAR) is discussed including a look at a LIDAR based study of the topography of the south bay.
We look at laser frequency noise and methods to suppress it by locking to a cavity or a molecular transition.
We conclude our look at time resolved spectroscopy by discussing techniques necessary for dealing with ultrafast pulses and an example of an ultrafast pump-probe experiment for analysis of charge carrier dynamics in organic polymers
We look at methods to generate short laser pulses including pump modulation, Q-switching, cavity dumping, and mode locking.
We look at methods of saturation spectroscopy to beat the doppler broadened line width when resolving spectral profiles.
Frequency Modulation Spectroscopy, Intracavity Spectroscopy and Cavity Ringdown spectroscopy are discussed.
We look at various mechanisms that change the shape of spectral lines including doppler broadening, pressure broadening, transit time broadening and saturation broadening
We look at properties of interferometers that are relevant for their use as measurements of wavelength.
We discuss wavelength measurement with spectrometers and investigate the properties of prism spectrometers and grating spectrometers
We investigate the energy levels of various common lasers and discuss what laser sources are applicable for producing light in various regions of the spectrum.
We discuss the interaction of light and matter in terms of a simple classical model of light as an oscillating driving field, matter as damped harmonic oscillators and the interaction as the driving of those damped harmonic oscillators by the light field.
Laser spectroscopy is an established field of chemistry and physics that uses the advantages of laser sources for spectroscopic measurements of atomic and molecular systems. This class covers laser sources, instrumentation, techniques and theory associated with the interaction of light and matter. It will provide both theoretical insight and provide an overview of experimental techniques that are relevant to this field.