Design and development of an external cavity diode laser for laser cooling and spectroscopy applications
Date
2006-12
Authors
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Journal ISSN
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Publisher
Stellenbosch : University of Stellenbosch
Abstract
External cavity diode lasers are used increasingly as sources of light in applications ranging from
industrial photonic systems to basic laboratory research on the interaction of light and atoms.
External cavity diode lasers offer more stable output frequency and narrow spectral bandwidth
than the typical free-running diode lasers. These characteristics are achieved by exploiting the
sensitivity of diode lasers to external optical feedback. In this study the design and development
of an external cavity diode laser system for future applications in spectroscopy and laser cooling
of rubidium atoms is presented. The external cavity diode laser including mechanical components
and control electronics of the system is developed from basic components. The system uses frequency
selective optical feedback from a diffraction grating in a Littrow configuration to provide
collimated, narrow-band, frequency tunable light near 780 nm. The external cavity diode laser is
designed to increase the mode-hop-free frequency tuning range, and allow accurate frequency tuning
and stabilisation. A low-noise current source and a temperature controller for thermal stability
were developed as part of the system since the output frequency changes with temperature and
current. The temperature controller is optimised experimentally for the thermal characteristics of
the external cavity. An electronic sidelock servo circuit for frequency locking of the external cavity
diode laser to an external reference for long term frequency stabilisation is proposed and discussed.
The servo circuit electrically controls the grating tilt and the current through the diode laser in
order to lock the frequency of the diode laser. The external cavity diode laser is optimised and
characterised near 780 nm. Results obtained in this study indicate that the external cavity diode
laser is suitable for future applications in spectroscopy and laser cooling of neutral rubidium atoms.
Description
Thesis (MSc (Physics))--University of Stellenbosch, 2006.
Keywords
Diode laser, Optical feedback, External cavity, Electronic control, Laser cooling, Spectrum analysis, Lasers -- Industrial applications, Diodes, Semiconductor, External cavity diode laser, Dissertations -- Physics, Theses -- Physics