## Ideas PageIn general, I am very interested in the operation of lasers. I have a decent basic understanding of laser operation, but would like to explore this topic more through my project for the summer. I am particularly interested in transverse laser modes. I have been doing research into previous experiments and papers regarding laser modes, and several ideas look promising as potential project topics. Here is a list of my ideas: ## Using Longitudinal Modes to Determine the Speed of Light:In exploring my interest in laser modes, I came across a paper
describing an experimental setup to determine the speed of light by
analyzing the longitudinal modes
in a laser. It involves measuring the beat frequency between different
longitudinal modes for several lengths of the laser cavity. Using
knowledge of the frequency
separation of longitudinal modes and the change in length, the speed of
light can be obtained from a graph of the data. This experiment seems
feasible with the
materials on hand, and provides an interesting application of the topic of
laser modes. A copy of the paper can be found ## Producing LG Modes with an End-Pumped Laser:I came across a paper describing the experimental observation of
Ince-Gaussian modes (see next idea). The experimental setup of this paper
was centered around an
end-pumped laser. The cavity would operate in higher order
Laguerre-Gaussian modes, but by breaking the symmetry Ince-Gaussian modes
were produced. Creating an
end-pumped laser setup that produces Laguerre-Gaussian modes may prove to
be a reasonably complex and worthwile project by itself. I found a ## Ince-Gaussian Modes:In addition to the well known Hermite-Gaussian (HG) and
Laguerre-Gaussian (LG) laser modes, there are also Ince-Gaussian
(IG) modes. These display elliptical symmetry,
as opposed to spherical or Cartesian (as in LG and HG modes). I find it
very interesting that HG and LG modes can be thought of as extreme cases
of IG modes where the
ellipticity is infinity and 0, respectively. Doing a project that explores
this relationship would be very interesting to me. I found a paper on the
experimental
production of IG modes, which can be found ## Fractal Laser Modes:
I found a paper discussing the production of fractal laser modes, which
looks very interesting. Fractals are a fascinating topic, and I am also
very interested in
laser modes, so this paper intrigued me. The experimental setup in the
paper seems relatively complicated, but perhaps I can conduct a simpler
version here at the
LTC. Fractal modes are achieved using an unstable cavity. According to the
paper, this can be attributed to the following: unstable cavities have
round-trip
magnification of M > 1, but a given mode must be the same when it
completes a round-trip around the cavity, thus giving rise to the
self-similar attribute of the
fractal mode. Again, I'm not sure I have the means to replicate their
experiment exactly, but it may be possible to make some
simplifications. The paper can be found ## Creating Optical Vortex Modes with a Single Cylinder Lens:This idea is directly from a previous project at the LTC by Hamsa Sridhar which I learned about through the paper. The project makes use of several different laser topics, including the form of the Gaussian beam and different types of laser modes. Although this project was already done here, perhaps I can do something similar or explore the original project from a different angle. |